Quick answer: The Molex Mini-Fit Jr. is a 4.20mm pitch wire-to-board and wire-to-wire crimp connector system — the family that Asia’s catalogue shorthand calls MX4.2 — built around the female crimp terminal 5556, the receptacle housing 5557, the male crimp terminal 5558 and the plug housing 5559, with the vertical header 5566 and the right angle header 5569 on the board side. Molex rates it 600V AC/DC (its UL and CSA columns; its IEC column says 250V) and publishes a 56-cell maximum-current table whose maximum is 9A at AWG #16 or #18 in a two- or three-circuit brass connector. The KONNRA KR4200 cross-references that family, and the single most important thing to know about it is that it is documented twice per interface with two different ratings: a 5A (20AWG) tier over 20# to 24# with insulation 1.10 to 1.80mm, and a 9A (16AWG) tier over 16# to 20# with insulation 3.10mm maximum. The 9A tier is the one that matches the original’s maximum, and its 3.10mm insulation ceiling is the same figure Molex publishes for 18 to 24 AWG. Three limits and one discrepancy are worth stating before anything else. At 20 AWG our single published figure is 5A against the original’s 7A for brass and 6A for phosphor bronze; neither of our tiers covers 26 or 28 AWG; and the 5A tier’s 1.80mm insulation ceiling is 1.30mm tighter than the original’s 3.10mm for the 18 to 24 AWG group. Our dielectric test level is 1,500V AC for one minute against the original’s 2,200V AC for one minute — and 2,200V is exactly what the original’s own formula yields at 600V. The original’s temperature ceiling depends on the contact base metal (brass +80°C, phosphor bronze +105°C) while we publish one figure for a terminal whose material section leaves the choice open.
I work on connector and harness programmes at KONNRA, so treat that disclosure as read: the KR4200 is one of the series I deal with, and this comparison is written from the manufacturer’s side. Everything below comes from manufacturer documents on both sides — two from Molex and four from us, plus our cross-reference page, our component pages and our site assets — and where two documents disagree, both figures are printed rather than averaged, reconciled or resolved in either party’s favour. That rule applies as much inside one company’s document set as it does across the two companies, and this round it applies a great deal inside our own.
KONNRA KR4200 series Mini-Fit 4.2 wire-to-board connector
👉 KR4200 cross-reference for the Molex Mini-Fit Jr. 5556/5557/5558/5559 series · KR4200 female terminal, wire-to-board · Wire-to-board connector range · Wire-to-wire connector range
What the Molex Mini-Fit Jr. Actually Is
Mini-Fit Jr. is one of the few connector families in the industry whose own specification states its scope in a sentence that a designer can design against without opening a drawing. Molex’s current product specification for the family opens with this:
“the MINI-FIT JR. 4.20 mm (.165 inch) centerline (pitch) printed circuit board (PCB) connector series with Tin or 30µ” Gold plating, and the MINI-FIT JR. connector series terminated with 16 to 28 AWG stranded, copper wire using Crimp technology with Tin or 30µ” Gold plating.”
Four things are fixed by that sentence alone. The pitch is 4.20mm, published with its imperial equivalent of .165 inch. The family is a crimp family, not an insulation-displacement or a screw family — wire is stripped, crimped into a terminal, and the terminal is inserted into a housing. The plating choice is tin or 30µ” gold, and the gold figure is the one that governs several of the mechanical and environmental rows later in the document, because Molex writes some of its durability and gas-test requirements specifically for the gold interface. And the wire range is stated as a whole: 16 to 28 AWG stranded, copper.
The architecture is the usual three-part wire-to-board system and the usual two-part wire-to-wire system, and it is worth separating those two because the KR4200 is documented for both interfaces separately and with two ratings per interface.
In the wire-to-wire configuration, both ends of the cable run carry a crimp terminal inside a housing, and the two housings latch to each other. In the wire-to-board configuration, the wire half is the same — female crimp terminal in a receptacle housing — and the board half is a header soldered to the PCB, in a straight (vertical) or right angle variant.
The series map, in the original’s own part numbers
The original publishes two series maps in the same document, one for each interface, and they overlap in exactly the place you would expect: the wire half.
| Interface | Function | Molex series |
|---|---|---|
| Wire-to-wire | Female crimp terminal | 5556 |
| Wire-to-wire | Receptacle housing | 5557 |
| Wire-to-wire | Male crimp terminal | 5558 |
| Wire-to-wire | Plug housing | 5559 |
| Wire-to-wire | Plug housing | 45776 |
| Wire-to-wire | Receptacle housings | 46992 / 46994 |
| Wire-to-wire | Plug housings | 46993 / 172646 |
| Wire-to-board | Female crimp terminal | 5556 |
| Wire-to-board | Receptacle housing | 5557 |
| Wire-to-board | Vertical header | 5566 |
| Wire-to-board | Right angle header | 5569 |
| Wire-to-board | Receptacle housings | 46992 / 46994 |
| Wire-to-board | Vertical headers | 172447 / 172647 |
| Wire-to-board | Right angle headers | 172448 / 172648 |
Three points follow from reading that map against the market shorthand. The female terminal 5556 and the receptacle housing 5557 are shared between the two interfaces and the male side is not, so a cross-reference that pairs a wire-to-board request against a male terminal and a plug housing is answering a wire-to-wire question. The four digits the market uses as shorthand describe only the wire half; a complete wire-to-board bill of materials also needs 5566 or 5569, or one of the 172447 / 172647 and 172448 / 172648 glow-capable headers. And the -210 suffix denotes the higher flammability grade — 5557-NR is UL 94V-2 and 5557-NR-210 is UL 94V-0 — while the P and P1 suffixes on the plug housings describe the presence or absence of wings, a distinction our cross-list gets wrong in two places.
What the original publishes about its wire side
The wire side is where the original’s document is at its most specific, and this is the layer that a harness shop actually works to. Molex publishes three applicable-wire windows by terminal, not one window for the family:
| Applicable wires (Molex, current specification) | Insulation |
|---|---|
| 16 AWG standard copper | 3.15 mm maximum |
| 18–24 AWG standard copper | 3.10 mm maximum |
| 22–28 AWG standard copper | 1.80 mm maximum |
The shape of that table is the thing to notice. It is not a single corridor with a floor and a ceiling; it is three overlapping bands whose insulation ceilings step down as the conductor gets finer, from 3.15mm at 16 AWG to 3.10mm across 18 to 24 AWG to 1.80mm across 22 to 28 AWG. A 20 AWG wire falls inside two of the three bands, so a 20 AWG wire with 2.5mm of insulation is acceptable to the original under its 18–24 AWG, 3.10mm window even though it would not be acceptable under the 22–28 AWG, 1.80mm window. The band is selected by the terminal, and the terminal is selected by the wire, so the two are not independent choices.
The wire-side mechanics are specified with unusual completeness, and two rows deserve to be read as design constraints rather than as test results.
The original also specifies a wire pullout force (axial, at 25 ± 6 mm per minute, without influence from the insulation crimp) per gauge as a minimum — 68.4 N at 16 AWG, 88.0 N at 18 AWG, 58.7 N at 20 AWG, 39.1 N at 22 AWG, 29.3 N at 24 AWG, 19.6 N at 26 AWG and 9.8 N at 28 AWG — with the non-monotonic shape printed as such, since the 18 AWG figure is the highest in the table rather than the 16 AWG one. It publishes the caveat that governs its use: “Wire pullout force is applicator dependent.”
The wire side of the family is also the subject of the second Molex document on our shelf, and that document is older and narrower. It is a variant-specific specification for a flanged right angle version of the family, dated 2007, and it publishes a shorter product list: terminal (AWG #18 to #24) 5556APBT(L); housing in UL 94V-2 as 5557-NR and in UL 94V-0 as 5557-NR-210; header assembly in UL 94V-2 as 5569-NB1 and in UL 94V-0 as 5569-NB1-210. It names an insulation window of 1.3mm to 3.1mm outside diameter, a rated voltage of 600V AC(rms)/DC, a temperature range of −40 to +105°C including terminal temperature rise, a contact resistance of 10 milliohm maximum measured at 20mV maximum and 10mA, an insulation resistance of 1000 megohm minimum at 500V DC, and a dielectric strength of 1500V AC(rms) for one minute.
That last figure is important, and it is the reason this article prints two dielectric values for the original rather than one. The older, variant-specific document says 1,500V AC for one minute. The current specification says 2,200 VAC for one minute. Both are Molex figures, both are on the same 4.20mm family, and they differ by 700V. They are not reconciled here, because the documents themselves do not reconcile them; the older one is scoped to a flanged right-angle variant and the newer one covers the family. What can be said is which document is which, and that is how both are reported throughout.
KONNRA KR4200 series dual row straight wafer, 4.20mm board header
The Ratings Side by Side
The table below is the whole comparison in one place. It is arranged so that a reader can see, row by row, which figures are level, which are not, and where a published figure comes from a different document than the row beside it. Where the original disagrees with itself, both of its values are printed in the same cell.
| Row | Molex Mini-Fit Jr. | KONNRA KR4200 | Verdict |
|---|---|---|---|
| Pitch | 4.20mm (.165 inch) | 4.20mm | Level |
| Rated voltage | 600V AC/DC (UL and CSA columns); IEC column 250V | 600V AC/DC (all four specifications) | Level against UL/CSA; not against the IEC column |
| Voltage basis | UL 1977 | Not stated | Original publishes its basis |
| Current | 56 cells: 2 base metals × 7 gauges × 4 circuit bands; maximum 9A | Two tiers: 5A (20AWG) and 9A (16AWG) | The 9A tier matches the maximum |
| Wire range | 16–28 AWG | 20#–24# (5A tier) or 16#–20# (9A tier) | Partial overlap; no 26 or 28 AWG |
| Insulation windows | 3.15mm / 3.10mm / 1.80mm (three windows) | 1.10–1.80mm (5A tier) or 3.10mm Max. (9A tier) | The 9A ceiling equals the original’s 18–24 figure |
| Operating temperature | −40 to +80°C brass; −40 to +105°C phosphor bronze | −40 to +105°C | Matches phosphor bronze only |
| Contact resistance, initial | 10 milliohms maximum | 10 milliohms Max. (dry circuit 20mV/100mA, EIA-364-23C) | Level |
| Insulation resistance | 1000 Megohms minimum at 500 VDC | 1000 Megohms Min. at 500V DC | Level |
| Dielectric withstanding voltage | 2,200 VAC for 1 minute (current spec); 1,500V AC(rms) for 1 minute (older variant spec) | 1500V AC for 1 minute | 700V below the current original; level with the older |
| Durability | 30 cycles → 20 mΩ max change | 30 cycles → 20 milliohms Max. | Level |
| Temperature rise basis | +30°C maximum | 30 Max. | Level |
| Heat resistance | 96 hours at 105 ± 2°C | 105 ± 2°C, 96 hours | Level |
| Cold resistance | 96 hours at −40 ± 3°C | −40 ± 2°C, 96 hours | Level figure, different tolerance band |
| Thermal shock | 5 cycles between −55 and 105°C | 5 cycles −40/+105°C | Different cold end |
| Terminal insertion force | 15.0 N maximum | 1.5 kgf (14.7 N) Max. | Within about 2% |
| Terminal retention force | 30 N minimum | 3.0 kgf (29.4 N) Min. | Within about 2% |
| Pin retention force | 9.81 N minimum | 1.0 kgf (9.8 N) Min. | Within about 2% |
| Per-circuit insertion | 14.7 N maximum | 1.50 kgf (14.71 N) per circuit maximum | Within 0.01 N |
| Per-circuit withdrawal | 0.5 N minimum | 0.10 kgf (0.98 N) per circuit minimum at first mate | Ours is about double |
| Housing material | Not stated in the electrical rows quoted here | PA66 UL94 V-0 or V-2 | — |
| Terminal material | Split by base metal throughout | Phosphor Bronze/Brass Tin Plated Over Nickel | Left open |
| Agency files | UL E29179 · CSA LR 19980 · IEC 61984 | UL E482542 | Original publishes more |
| Glow wire | Named series, EN 60695-2-11 / IEC 60695-2-11, 750°C / 2 s | None published | Gap on our side |
| Solderability | 95% minimum coverage per SMES-152 | No clause in PS-KR4200-01 | Gap on our side |
Read the current row first, then read the insulation row, then read the temperature row. Those three carry the whole argument of this article, and they are the three where a buyer who reads only one document from each side is most likely to reach a conclusion that the other document contradicts. The next three sections take them one at a time.
Two Specifications, and the Tier That Matters Is in the Second One
Start with the fact that decides whether the KR4200 is a 5A part or a 9A part, because that question has two published answers and both of them are ours.
KONNRA documents the KR4200 in four product specifications, all Edition A1, all dated 2022/2/26, and two per interface — one for wire-to-board and one for wire-to-wire, each in a 5A version and a 9A version. The four documents share one document-number block and one date, and two of them carry the same subject line as each other. Nothing in the file names distinguishes the 5A tier from the 9A tier. Only the contents do.
What each of the four KONNRA documents publishes
| Document | Subject line | Pages | Rated current | Applicable wire | Insulation O.D. | Terminals listed |
|---|---|---|---|---|---|---|
| PS-KR4200-01 | Wire To Board Connector Specification | 7 | 5A (20AWG) | AWG 20#~24# | 1.10~1.80 mm | T4200F*T0102A |
| PS-KR4200-02 | Wire To Board Connector Specification | 7 | 9A (16AWG) | AWG 16#~20# | 3.10 mm Max. | T4200FB***01B |
| PS-KR4200-03 | Wire To Wire Connector Specification | 6 | 5A (20AWG) | AWG 20# ~ 24# | 1.1 to 1.8 mm | T4200F*T0102A, T4200MBT0102A |
| PS-KR4200-04 | Wire To Wire Connector Specification | 6 | 9A (16AWG) | AWG 16# ~ 20# | 3.10 mm Max. | T4200FB***01B, T4200MBT0101A |
Three things follow immediately from that table, and each of them has a commercial consequence.
The first is that “the KR4200 is a 5A connector” is true of exactly half of our documentation. PS-KR4200-01 and PS-KR4200-03 publish 5A (20AWG) over 20# to 24# with insulation 1.10 to 1.80mm. PS-KR4200-02 and PS-KR4200-04 publish 9A (16AWG) over 16# to 20# with insulation 3.10mm maximum. A customer who asks for “the KR4200 specification” and is sent one file has a fifty per cent chance of receiving the tier that does not match the requirement they came with, and nothing in either file’s title tells them a second file exists.
The second is that the two tiers use different terminal part numbers, so they are not the same product with a different label on the box. The 5A tier uses T4200F*T0102A on the wire-to-board side and adds T4200MBT0102A for the mating half on the wire-to-wire side. The 9A tier uses T4200FB***01B and adds T4200MBT0101A. The 9A terminal is a different part number, which means a customer who is upgraded from the 5A tier to the 9A tier is changing the terminal — and therefore the crimp tooling, the crimp settings and the applicator — not just the data sheet.
The third is that the four documents agree on everything else that matters at the top level. All four publish the same Rated Voltage (Max.) 600V AC/DC, and all four publish the same Ambient temperature Range −40~+105. So voltage and temperature are family statements; current, wire range and insulation diameter are tier statements. That split is worth holding onto, because it means the two figures a designer is most likely to check first are the two that will not warn them that a tier decision exists.
KONNRA KR4200 series dual row right angle wafer, 4.20mm board header
Why the 9A tier changes the answer
Now put the two tiers against the original’s table, because the original does not publish one current figure either — it publishes fifty-six.
Molex’s maximum-current table is organised as two base metals × seven gauges × four circuit bands: brass and phosphor bronze, AWG #16 through #28, and circuit bands of 2–3, 4–6, 7–10 and 12–24. The full table, as published:
| AWG | Brass: 2&3 ckt / 4–6 / 7–10 / 12–24 | Phosphor Bronze: 2&3 ckt / 4–6 / 7–10 / 12–24 |
|---|---|---|
| #16 | 9 / 8 / 7 / 6 | 8 / 7 / 6 / 5 |
| #18 | 9 / 8 / 7 / 6 | 8 / 7 / 6 / 5 |
| #20 | 7 / 6 / 5 / 5 | 6 / 5 / 4 / 4 |
| #22 | 5 / 4 / 4 / 4 | 4 / 3 / 3 / 3 |
| #24 | 4 / 3 / 3 / 3 | 3 / 2 / 2 / 2 |
| #26 | 3 / 2 / 2 / 2 | 2 / 1 / 1 / 1 |
| #28 | 2 / 1 / 1 / 1 | 1 / 1 / 1 / 1 |
The maximum in that table is 9A, and it occurs at AWG #16 or #18 in a two- or three-circuit brass connector. Phosphor bronze tops out one amp lower at the same gauges, at 8A. So the original’s headline capability is a 9A capability, in a specific metal, at a specific gauge, in a specific circuit band — and it is not a capability the family carries at every gauge or in every circuit count.
Our 9A tier matches that maximum exactly. PS-KR4200-02 and PS-KR4200-04 publish 9A (16AWG), the same nominal current at the same nominal conductor as the original’s ceiling. That is the single strongest published correspondence between the two families on the current row, and it is only visible in the second document of each interface.
And our 9A tier’s insulation ceiling of 3.10mm is the same figure Molex publishes as its 18 to 24 AWG maximum. That is a second, independent correspondence, and it is the kind of figure that only lines up when two companies sized the same 4.20mm contact system around the same conductor family.
Now the honest half. At the gauges where both sides publish a figure for the same conductor, our single number is lower than the original’s. At 20 AWG, the original publishes 7A for brass and 6A for phosphor bronze in a two- or three-circuit connector, while our 5A tier publishes 5A. So at 20 AWG we are 2A below the original’s brass figure and 1A below its phosphor bronze figure, and our own 9A tier does not reach 20 AWG in a way that closes the gap — the 9A tier’s window is 16# to 20#, but the 9A figure is stated as the tier’s rating rather than as a per-gauge table, so it cannot be read as a derating curve.
That distinction matters more than it looks, and it is the reason this article does not simply declare a 20 AWG match. A tier rating is a statement about the tier’s best case; the original’s table is a statement about every case it publishes. Where we publish one number and the original publishes a grid, the honest comparison is at the grid’s cell, not at the tier’s label. At 16 and 18 AWG the cell and the label agree at 9A, which is why the tier match is real. At 20 AWG the cell is 7A or 6A and our number is 5A, which is why the gap is real too.
The reason this is a matter of documentation rather than of product is our own website. The terminal component page for the wire-to-board female terminal publishes Current (Max) 9A — the high tier’s figure — and pairs it with Wire/Cable Size (AWG) 18#-22# and Insulation Diameter 2.50mm (MAX). Neither of those two windows appears in any of the four specifications. The specifications publish 20#–24# with 1.10–1.80mm and 16#–20# with 3.10mm Max., so the website’s wire window and insulation ceiling are a third combination that exists only on the website. And a media asset in our own library is titled “KR4200 4.2mm Pitch 5A current single or dual row connector”, which publishes the low tier in a file name.
So a buyer can find 5A or 9A, and one of three wire windows, depending on which page they open. That is not a product problem; the four specifications are internally consistent on voltage and temperature and differ on current and wire range in a way that is coherent once the tier is named. It is a documentation problem, and it is fixed by naming the tier on the part number and in the quotation rather than by reading whichever page loads first.
A 600V Rating Carrying a 1,500V Test Level
Both families publish a 600V rating. Only one of them publishes a dielectric test level that its own rating implies.
A dielectric withstanding voltage test is not a second rating and is not marketed as one, but it is not decorative either: it is the test that establishes that the insulation system survives a fault-level overvoltage for a defined period without breaking down or flashing over. The level a manufacturer chooses is normally derived from its own rated voltage by a fixed rule, and the original states the rule by publishing the arithmetic’s result.
The formula the original uses
Molex publishes dielectric withstanding voltage 2,200 VAC for 1 minute between adjacent terminals and to ground, with the requirement “No breakdown. Current leakage < 5 mA”. At the family’s own 600V rating, that number is exactly two times the rated voltage plus 1,000 volts:
2 × 600 + 1000 = 2200
That is the rule the original is applying, and the arithmetic is clean enough that it can be treated as the original’s own formula rather than as a coincidence: twice the rated voltage, plus one thousand volts. The 1,000V constant is the part that makes the test meaningful at low voltages — a 250V system tested at 500V would be a weak test, whereas at 1,500V it is a real insulation check — and the doubling is the part that keeps the margin proportional as the rating rises.
Now run the same formula on a 250V system and a 600V system and notice what happens to the answer. At 250V the formula yields 1,500V. At 600V it yields 2,200V. Those two results are 700V apart, and the reason this article spends a section on the point is that our 1,500V test level appears at both ratings.
And there is a second Molex figure that must sit beside the 2,200V one and not be lost. The original’s older, variant-specific flange document publishes a dielectric strength of 1,500V AC(rms) for one minute — the same 1,500V our specifications publish, on a document that also states a 600V rated voltage. So the original’s own document set contains a 1,500V level at a 600V rating and a 2,200V level at a 600V rating, and this article prints both rather than choosing. The current specification is the one that carries the arithmetic; the older document is the one whose scope is narrower.
And where our number comes from
All four KR4200 specifications publish the same dielectric strength: 1500V AC for one minute between adjacent terminals or ground, per EIA-364-20A, with the requirement that there be no breakdown and no flashover.
Our figure is not an error in transcription. It is a house figure, and the evidence that it is a house figure is that the same 1,500V value appears in our 250V-rated 3.00mm, 3.96mm wire-to-board and 3.96mm board-in specifications as well. One number carried across series is a documentation convention; one number derived per series from that series’ rated voltage is a derivation. Ours reads as the former.
The contrast with the immediately preceding comparison in this series is worth stating plainly, because the two rounds point in opposite directions on the same row. In the 3.00mm round the original published the formula and our 1,500V happened to equal it evaluated at our own 250V rating, so the two documents were consistent with each other even though the numbers differed from the original’s. Here our rating is 600V and 1,500V is not what the formula yields at 600V, so the two are not consistent. Same house figure, different rating, opposite conclusion. A design that was signed off against the 3.00mm precedent and carried across to the 4.20mm series would import an inconsistency along with the number.
What this does and does not mean has to be stated carefully, because the temptation is to overread it.
- It does not mean the connector fails a 2,200V test. No such result is published on either side. The claim is about documents: the original publishes 2,200V, we publish 1,500V, and the original’s own formula at our rating calls for 2,200V.
- It does not mean the 600V rating is unsupported. It is published in all four specifications and on the terminal page, so it is stated consistently across our documentation.
- It does mean that a qualification programme taking the original’s dielectric row as its acceptance criterion will find our published value 700V short, and that this is a document request rather than a substitution decision.
The request that follows from this section is therefore a specific one, and it belongs in the call to action rather than in the body as an assertion. A customer who needs the row to line up asks us for the dielectric test level as tested on the specific terminal and housing part number they are buying, and asks whether the 1,500V figure is a family convention or a per-series derivation. Where our own four specifications and our own component page disagree about what the tier is, only a document request can settle it — and that request is one of the five in the section on the questions I would ask us.
Temperature: the Original Splits by Base Metal, We Do Not
This is the third load-bearing difference, and it is the one with the shortest paper trail and the largest consequence.
Brass at +80°C, phosphor bronze at +105°C
Molex publishes its operating and nonoperating temperature ranges split by the contact’s base metal, in the same document whose current table is also split by base metal:
| Terminal base metal | Molex operating | Molex nonoperating |
|---|---|---|
| Brass | −40°C to +80°C | −40°C to +80°C |
| Phosphor bronze | −40°C to +105°C | −40°C to +105°C |
The document’s footnote attaches a condition to both rows: “Including 30°C terminal temperature at rated current”. That is the same 30°C rise figure the current table is built on, so the temperature rows and the current rows are one statement rather than two.
KONNRA publishes one figure. All four KR4200 specifications publish an ambient temperature range of −40 to +105°C. The component page for the wire-to-board female terminal publishes Operating Temperature Range −40°C to 105°C. So the +105°C figure is consistent across our documentation.
The problem is not the figure. The problem is the material it is claimed for. Our specifications’ materials section reads “Terminal: Phosphor Bronze/Brass Tin Plated Over Nickel”, and the wafer entry reads Contact: Brass Tin Plated Over Nickel. The material section does not choose a metal; it lists both. Meanwhile our cross-reference page describes every terminal as brass: 5556T2 → T4200FBT0102A and 5556T3 → T4200FBT0104B on the female side, 5558T2 → T4200MBT0102A and 5558T3 → T4200MBT0101A on the male side, each row naming brass as the material and distinguishing stamp-then-tin-plate from pre-plated, that is tin-plate-then-stamp. So the cross-list chooses brass, four times out of four, where the specification leaves the choice open.
Put those two facts together and the temperature row has two possible readings, and both must be printed:
- If the terminal is brass, our published +105°C exceeds the original’s own ceiling for a brass contact by 25°C.
- If the terminal is phosphor bronze, our published +105°C matches the original’s phosphor bronze figure exactly.
Only one of those two readings is safe, and which one applies depends on a field in our own document that is not filled in. That is the whole of the finding, and it is why this section asks for a document rather than making a claim.
And brass is the better metal for current
There is a counter-intuitive half to this that the original’s own table publishes, and it is the reason the material question cannot be deferred until the temperature question comes up.
Look at the original’s current table again and read the two metals side by side at the top of the range. At AWG #16 and #18, in a two- or three-circuit connector, brass is rated 9A and phosphor bronze is rated 8A. Brass is rated higher than phosphor bronze for current. Cross-reference that against the temperature rows and the two metals swap places: phosphor bronze is rated to +105°C and brass only to +80°C.
So brass is the better metal for current and the worse metal for temperature, and phosphor bronze is the better metal for temperature and the worse metal for current. Neither metal is simply better, and the choice is a real engineering trade rather than a purchasing preference. The consequence for a cross-reference is direct: if a customer’s requirement is 9A at 18 AWG in a three-circuit connector and operation above +80°C, the original does not satisfy both rows with one metal either — it satisfies the current row with brass and the temperature row with phosphor bronze, and at 18 AWG in a three-circuit connector phosphor bronze is rated 8A rather than 9A. The trade exists on both sides of the comparison, and the difference is that the original documents it and we currently leave it open.
The material question reaches the cross-list too, which names brass on every terminal row while carrying the mapping defects documented below, so the declaration should be requested from the controlling document.
KONNRA KR4200 series dual row female housing for the Mini-Fit Jr. 4.20mm pattern
The Mechanical Layer: Three Figures Within About Two Percent
The mechanical layer is where these two families are closest, and it is reported here as a supporting section rather than as the headline, because agreement is the least interesting thing a comparison can find and it is also the easiest to overstate.
Three independent figures — a retention force, an insertion force and a pin retention force — land within about two per cent of each other.
| Figure | Molex | KONNRA | Gap |
|---|---|---|---|
| Crimp terminal insertion force (into housing) | 15.0 N (3.37 lbf) maximum | 1.5 kgf (14.7 N) Max. | About 2% |
| Crimp terminal retention force (in housing) | 30 N (6.74 lbf) minimum | 3.0 kgf (29.4 N) Min. | About 2% |
| PC tail header pin retention force / pin retention | 9.81 N (2.20 lbf) minimum | 1.0 kgf (9.8 N) Min. | About 0.1% |
These are three different physical quantities, measured in three different directions, on three different parts of the system — a terminal being pushed into a housing, a terminal being pulled out of a housing, and a header pin being held in a printed circuit board. They are not one measurement reproduced three times, and that is what makes the agreement worth a table rather than a sentence. Molex publishes its pin retention row for solid and stamped PC tail header pins; our pin-to-pin retention force row is specified as an axial push force of 1.0 kgf (9.8 N) minimum; and both sides publish the terminal-to-housing retention as an axial pull-out.
The test conditions are also close enough to compare, which is not always true across companies. Molex specifies its per-circuit mate and unmate test at 25 ± 6 mm per minute, with latch disabled. Our §6.1 points to §8.0 and states 25.4 ± 3 mm per minute, excluding plastic detents, per EIA-364-13D. The speeds overlap across their whole ranges — the original’s window is 19 to 31 mm per minute and ours is 22.4 to 28.4 — so the two sets of numbers describe the same operation at compatible rates. The exclusion clauses differ in wording and agree in intent: “with latch disabled” and “excluding plastic detents” both remove the latch’s contribution from the figure, which is what makes a contact-level force comparable between designs with different latch geometries.
Two figures in the original’s mechanical section have no counterpart on our side. The first is normal force — a minimum contact normal force of 1.47 N (150 grams) for tin and 0.49 N (50 grams) for gold — which is the load the socket contact applies to the pin and therefore the quantity that contact resistance and vibration performance sit downstream of; we publish no normal-force figure. The second is the panel, latch and PCB engagement block, listed in the section below.
And the per-circuit window
The mechanical agreement has a second form, and it is the one that a harness engineer will actually use, because mating force is specified per circuit rather than per connector.
Molex’s current specification gives the per-circuit figures directly: 14.7 N (3.30 lbf) maximum insertion force and 0.5 N (0.11 lbf) minimum withdrawal force per circuit, measured at 25 ± 6 mm per minute with the latch disabled. Our §8.0 table is published as a whole-connector ladder for the single row family, with an insertion maximum and two withdrawal minima — at initial and at the thirtieth cycle:
| Circuits (single row) | Insertion force max | Withdrawal force min, initial | Withdrawal force min, 30th cycle |
|---|---|---|---|
| 2 | 3.00 | 0.20 | 0.15 |
| 3 | 4.50 | 0.30 | 0.25 |
| 4 | 6.00 | 0.40 | 0.30 |
| 5 | 7.50 | 0.50 | 0.40 |
| 6 | 9.00 | 0.60 | 0.50 |
Units in that table are kgf as published. A dual-row table follows in the same clause.
Two clean per-circuit constants fall out of that table, and they are the reason the comparison can be made at all. The insertion column is a flat 1.50 kgf per circuit across all five rows — 3.00 over 2, 4.50 over 3, 6.00 over 4, 7.50 over 5 and 9.00 over 6 all divide to 1.50 — which is 14.71 N per circuit. The initial withdrawal column is a flat 0.10 kgf per circuit — 0.20 over 2 through 0.60 over 6 all divide to 0.10 — which is 0.98 N per circuit.
Now put those against the original’s per-circuit figures.
- Insertion: the original’s 14.7 N per circuit maximum against our 14.71 N per circuit maximum. The two agree to within 0.01 N per circuit.
- Withdrawal: the original’s 0.5 N per circuit minimum against our 0.98 N per circuit minimum at first mate. Our guaranteed floor is about double the original’s.
And the per-circuit basis itself is defensible on the original’s own evidence, which is a cross-check that makes the comparison legitimate rather than convenient. The original’s older, variant-specific flange document publishes a whole-connector insertion and withdrawal force table with a first-cycle, sixth-cycle and thirtieth-cycle column for 10, 12, 14, 16 and 20 circuits. Every withdrawal minimum in that table divides to exactly 0.49 N per circuit — 4.90 over 10, 5.88 over 12, 6.86 over 14, 7.84 over 16 and 9.80 over 20 — which is the same figure as the current specification’s 0.5 N per circuit minimum. So the two Molex documents agree with each other, and the per-circuit figure is additive rather than averaged. The same table’s insertion maxima divide to 14.21 N per circuit against the current specification’s 14.7 N per circuit — a difference of about three per cent between two of the original’s own documents, which is stated here rather than smoothed.
Three caveats belong with that comparison.
The first is that the ladder decays, and it is supposed to. Our withdrawal column carries a 30th-cycle figure lower than the first-mate figure at every circuit count — 0.15 against 0.20 at two circuits, 0.50 against 0.60 at six. A designer who takes the first-mate figure as the service-life figure is reading half the table.
The second is that the two companies’ per-circuit numbers are not the same kind of number. Both sides publish an insertion maximum and a withdrawal minimum, and the two rows measure good news in opposite directions: lower insertion is better for assembly, higher withdrawal is better for retention. A table that ranks one company above the other on “force” without saying which row it means has said nothing.
The third is provenance. The per-circuit-count table whose division produces the 0.49 N and 14.21 N figures comes from the original’s older, variant-specific document, scoped to a flanged right-angle variant and dated 2007, not from the current specification.
The Electrical Rows That Match Exactly
The electrical layer is the most straightforward part of this comparison, and it is also the part that most often gets reported as a headline. It is a supporting section here.
| Row | Molex | KONNRA | Basis on our side |
|---|---|---|---|
| Contact resistance, initial | 10 milliohms maximum, at maximum 20 mV and 100 mA with wire resistance removed | 10 milliohms Max. | Dry circuit 20mV/100mA, EIA-364-23C |
| Insulation resistance | 1000 Megohms minimum at 500 VDC | 1000 Megohms Min. | 500V DC for 1 minute, adjacent contacts, EIA-364-21B |
| Durability | 30 cycles at maximum 10 cycles per minute → 20 milliohms maximum change from initial | 30 cycles at 10 cycles/min → 20 milliohms Max. | EIA-364-09C |
| Temperature rise | +30°C maximum, by current cycling | 30 Max. | EIA-364-70B |
| Heat resistance | 96 hours at 105 ± 2°C → 20 milliohms max change | 105 ± 2°C, 96 hours | EIA-364-17B |
| Cold resistance | 96 hours at −40 ± 3°C → 20 milliohms max change | −40 ± 2°C, 96 hours | EIA-364-59 |
| Thermal shock | 5 cycles between −55 and 105°C, dwell 0.5 hours each | 5 cycles −40°C 30 min / room 5 min / +105°C 30 min / room 5 min | EIA-364-32B |
Read that table for the level rows and it is a match on every one of them. Contact resistance is 10 milliohms maximum on both sides, measured the same way — the original specifies maximum 20 mV and 100 mA with the wire’s resistance removed, and our §5.1 specifies a dry circuit at 20mV and 100mA per EIA-364-23C. Insulation resistance is 1000 megohms minimum at 500V DC on both sides, and our clause names the same 500V DC for one minute between adjacent contacts. Durability is 30 cycles on both sides at the same rate of 10 cycles per minute, with the same 20 milliohms maximum change from initial. Temperature rise is 30°C on both sides. Heat resistance is 96 hours at 105 ± 2°C on both sides. Cold resistance is 96 hours at −40°C on both sides, with the original’s tolerance at ± 3°C and ours at ± 2°C — the same nominal figure with different tolerance bands, and the tolerance is printed rather than harmonised.
One row is level in its nominal cold end and not in its test ladder. The original’s thermal shock clause runs 5 cycles between −55 and 105°C with a 0.5 hour dwell at each; ours runs 5 cycles of −40°C for 30 minutes, room for 5 minutes, +105°C for 30 minutes, room for 5 minutes, per EIA-364-32B. The cycle count is the same at 5, the hot end is the same at +105°C, and the cold end is different: −55°C on the original against −40°C on ours. That is the one figure here where the same test name hides a different severity.
And the post-humidity row is where our own numbers part company with the original. The original’s general insulation-resistance requirement is 1000 megohms minimum. Our §7.7 humidity test — 40 ± 2°C, 90 to 95% RH, 96 hours per EIA-364-31B — requires contact resistance within 20 milliohms, the dielectric requirement of §5.3, and insulation resistance of 100 megohms minimum. That is an order of magnitude below the 1000 megohm figure, and the identical post-humidity figure appears in our 2.5mm, 2.54mm, 3.00mm, 3.96mm and 4.20mm specifications, so it is a house clause stated here as the published value rather than as a match.
Two environmental rows in the original’s document differ in kind rather than in value. Molex specifies random vibration per EIA 364-28 test condition VII letter D, 15 minutes in each axis; ours is a sinusoidal sweep, 1.5mm peak-to-peak, 10 to 55 to 10 Hz in one minute, 2 hours in each X.Y.Z axis, per EIA-364-28B, with the same acceptance requirements. Same standard number, different excitation — a swept sine at 1.5mm displacement and a random profile are not interchangeable, and two hours per axis is a longer exposure than fifteen minutes per axis. On shock, both sides publish 50 g: Molex specifies a half sine wave of 11 milliseconds in ±X, ±Y and ±Z axes, 18 shocks total, while ours states 490 m/s² (50g), 3 strokes in each X.Y.Z axis, per EIA-364-27B and publishes no pulse duration or waveform.
KONNRA KR4200 series female crimp terminal, brass tin plated over nickel
The Wire and Insulation Windows
This is the section to read before a quotation, because it is where three documents become four windows and one of them is 1.30mm tighter than the original’s.
| Side | Wire range | Insulation window |
|---|---|---|
| Molex, 16 AWG | 16 AWG | 3.15 mm maximum |
| Molex, 18–24 AWG | 18–24 AWG | 3.10 mm maximum |
| Molex, 22–28 AWG | 22–28 AWG | 1.80 mm maximum |
| KONNRA, 5A tier | 20#–24# | 1.10–1.80 mm |
| KONNRA, 9A tier | 16#–20# | 3.10 mm Max. |
| KONNRA, terminal component page | 18#–22# | 2.50mm (MAX) |
Five consequences follow from putting the two companies’ windows in one table, and they are the whole of the wire-range finding.
The first is that we do not cover 26 or 28 AWG on either tier. The original’s range runs to 28 AWG — with published current figures down to 2A for brass and 1A for phosphor bronze at 28 AWG in a two- or three-circuit connector, and with an insulation window of 1.80mm available for the fine-wire group. Our 5A tier starts at 20# and our 9A tier starts at 16#, so the whole fine-wire end of the original’s family has no counterpart in our published documentation. A 26 or 28 AWG harness requirement is therefore not a cross-reference question at all; it is a coverage question.
The second is that the 5A tier’s insulation ceiling is 1.30mm tighter than the original’s for the 18 to 24 AWG group. The original allows 3.10mm there; our 5A tier allows 1.80mm. Subtract one from the other and the gap is 1.30mm — and the practical consequence is concrete: a 20 AWG wire with 2.5mm of insulation is acceptable to the original under its 18–24 AWG window and is outside our 5A tier’s ceiling. That wire exists in most harness catalogues. So the tightest published insulation limit in this comparison is ours, on the tier that most customers will be sent first.
The third is that the two tiers constrain opposite ends, and the website constrains neither. Our 5A window runs 1.10 to 1.80mm, so it has a floor and a ceiling, while the original’s 18 to 24 AWG window has 3.10mm maximum only — so a very thin-insulated 20 or 22 AWG wire sits outside our 5A floor and inside the original’s window. Our 9A window is 3.10mm Max. with no minimum, which makes the higher-current tier the looser one, the opposite of the intuition that a bigger-current part takes a bigger wire. And the terminal component page publishes a third window, 18# to 22# with 2.50mm maximum, which belongs to neither tier: it agrees with the 5A tier below 1.80mm and diverges exactly where the difference matters, at 2.0 to 2.5mm of insulation, where the page and the 9A tier say yes and the 5A tier says no.
And the crimp settings follow the window rather than standing apart from it. Our §6.5 publishes conductor crimp heights of 1.05 / 1.00 / 0.87 ± 0.05mm for 20 / 22 / 24 AWG, an insulation crimp width of 2.30mm maximum with insulation crimp heights of 1.65 / 1.55 / 1.45mm maximum, a stripping length of 2.6 to 3.2mm, and crimp strengths of 6.80 / 4.54 / 3.63 kgf minimum at those three gauges. Those settings exist in PS-KR4200-01 and are published for the 20, 22 and 24 AWG conductors that the 5A tier accepts. A customer who moves to the 9A tier’s 16# to 20# range is moving to a different terminal part number with different crimp geometry, and the settings for the 9A terminal are in PS-KR4200-02 rather than in the file that was sent with the quotation. The stripping length in particular is a bench setting rather than a purchase-order field, and a bench set up for a 20 AWG crimp will need a second setting for a 16 AWG one.
What the Original Publishes That We Do Not
Every comparison of this kind accumulates a list of rows that exist on one side only, and the honest way to publish it is as a list of requests rather than as a list of faults. This is that list.
Agency files with numbers. Molex publishes UL File E29179, CSA Certificate LR 19980, and IEC 61984 tested with an NRTL type-examination certificate available on request, plus a per-series table showing UL(600V), CSA(600V) and IEC(250V). Our component pages publish UL E482542 only. If an approval file references a CSA registration, that is a gap to close with us and not a feature to assume. The per-series voltage table is the more interesting absence, because it is the mechanism by which the original publishes two different voltages for one family: the UL and CSA columns rate the family 600V and the IEC column rates it 250V, and Molex publishes both columns rather than one.
A current table by material, gauge and circuit count. The original gives 56 cells; we give one figure per tier. A tier figure cannot be derated by the reader, because a tier figure states no curve. Where both sides accept 20 AWG, the original answers 7A or 6A depending on metal and circuit count and we answer 5A — a comparison that is possible only because one side published a grid.
A temperature table by base metal. The original gives +80°C for brass and +105°C for phosphor bronze; we give one figure for a terminal whose material section lists both metals. This is the row where a published table on the original’s side and an open field on ours combine into a question that neither of us has answered in print. Molex also publishes the footnote “Including 30°C terminal temperature at rated current”, which ties its temperature rows to its current rows.
Glow-wire capability. Molex names the series — 46992, 46993, 46994, 172646, 172447, 172448, 172648 and 45776 — and publishes the test standard as EN 60695-2-11-2001 / IEC 60695-2-11-2000, with an additional investigation for EN 60335-1 / IEC 60335-1 at 750°C for 2 seconds with no flaming, and a VDE test report on request. We publish no glow-wire data at all. For an appliance or lighting application where an unattended-connector glow-wire test is specified by the end-product standard, that is a documented gap rather than a design difference.
Wave solder process temperature, by header plating and peg type and normal force. Molex publishes 240°C maximum with pegs, 260°C maximum without pegs and with matte tin over nickel, 240°C for bright tin over nickel, 240°C for tin over copper and 220°C with pegs for the glow-wire series, and states plainly that “For Headers: Matte tin over Nickel plating is recommended for new applications.” It also publishes normal force minima of 1.47 N (150 grams) for tin and 0.49 N (50 grams) for gold. We publish no wave solder window, no plating-dependent maximum and no normal-force figure.
Panel, latch and PCB engagement mechanics. 225 N maximum panel insertion, 157 N dual row and 133 N single row minimum panel withdrawal for 5559, 46993 and 172646; 225 N maximum and 133 N minimum for 45776; 22.24 N (5.0 lbf) maximum thumb latch operation force; 68 N (15.3 lbf) minimum thumb latch yield strength; and PCB engagement forces of 26.7 to 66.7 N for the right angle headers and 4.4 to 44.5 N for the straight headers, marked “For Reference ONLY”. We publish none of these, and the thumb latch rows in particular have no counterpart because our published wafer and housing range is described without a latch-force specification.
Environmental programmes, solderability, packaging and harness guidance. The original publishes mixed flowing gas to EIA-364-65 Class IIa, 10 days mated, for 30µ” gold plated parts only, and cyclic temperature and humidity to EIA-364-1000.01, 24 cycles from 25°C/80% RH to 65°C/50% RH with a 0.5 hour ramp and a 1 hour dwell — we publish neither. It also publishes solderability at 95% minimum coverage per SMES-152, a solder resistance dip of 5 ± 0.5 seconds at maximum solder temperature, the nylon moisture warning, and the test-plug recommendation (Series 44281) with its instruction that standard mating parts must not be used for harness testing. Our PS-KR4200-01 carries no solderability clause, no packaging guidance for moisture-sensitive nylon, no test-plug recommendation, and no equivalent of the original’s cable-tie free-length table, which runs from 12.7mm at 2 to 6 dual row and 2 to 3 single row to 44.45mm at 22 to 24 dual row and 11 to 12 single row — a bench figure that controls how much bending load reaches the crimp.
And two rows where the absence runs the other way. The original’s older flange document publishes a salt spray test of 48 ± 4 hours at 35 ± 2°C from a 5 ± 1% solution and an SO2 gas test of 50 ± 5 ppm for 24 hours at 40 ± 2°C, plus solderability at 230 ± 5°C for 3 ± 0.5 seconds and resistance to soldering heat at 260 ± 5°C for 5 ± 0.5 seconds. The current Molex specification contains no salt spray clause and ours has none either, so the correct statement is the absence of a comparison rather than a comparison.
Where Our Own Documents Disagree With Each Other
This is the longest defect list in this comparison series so far, and all of it is ours. Each item ends in the request that closes it rather than in a conclusion about what we intended.
- The series publishes two tiers and the website matches neither. The specifications publish 5A / 20#–24# / 1.10–1.80mm and 9A / 16#–20# / 3.10mm Max.; the terminal component page publishes 9A with 18#–22# and 2.50mm; a media asset is titled “KR4200 4.2mm Pitch 5A current single or dual row connector”. A buyer can find 5A or 9A, and one of three wire windows, depending on which page they open.
- All four documents share one document-number block and one date. They are Edition A1 dated 2022/2/26, and two carry the same subject line as each other — PS-KR4200-01 and PS-KR4200-02 are both headed Wire To Board Connector Specification. Nothing in the file names distinguishes the tiers; only the contents do.
- One KONNRA part number is mapped to two Molex references whose own descriptions contradict each other. H4200F2111602A appears for both 5559-22P (with wings, clear) and 5559-22P1 (without wings, clear); H4200F2121602A appears for both 5559-24P and 5559-24P1. The suffix difference is exactly the wings.
- One part number is mapped to both flammability grades of the same housing. H4200M2011601A is mapped to 5557-02R (clear) and to 5557-02R-210 (white PA66 UL94-V0), where Molex’s own document distinguishes 5557-NR (UL 94V-2) from 5557-NR-210 (UL 94V-0). A flammability grade is a row in a safety file, not a cosmetic difference.
- The 22-circuit row carries two position counts in the same column. 5557-22R-210 → H4200M2110101A is described as 2X10P, while 5557-22R → H4200M2111601A is described as 2X11P.
- A plug housing is mapped against board headers. The cross-list puts 5559-nnA4 references against our single-row right-angle DIP wafers, although Molex’s own map lists 5559 as a Plug Housing and 5569 as the Right Angle Header. The 5569-nnA2 pairing is the one that matches the original’s map.
- The Standard column answers a different question from the one a designer is asking. It reads RoHS/REACH on every row, and the cross-list has no electrical column at all: no voltage, no current, no temperature, no wire range and no insulation diameter.
- The page a search finds first publishes no electrical specification whatever. “Molex 5557 Cross-Reference: KR4200 MX4.2 Connector Guide” is a structured catalogue record with headings such as Technical Specifications and Procurement Action, and no voltage, no current, no temperature and no contact resistance, stating that “Detailed dimensional and electrical datasheets are not itemized in the current catalog record.”
None of those eight items is a product decision. Every one is a publication decision, closed by naming a tier on a document, choosing a metal on a drawing, or correcting a mapping row — which is why the requests that follow are all document requests.
KONNRA KR4200 series male crimp terminal, brass tin plated over nickel
The Cross-Reference Map
Our cross-reference for this family is a real HTML table of about 110 rows, with columns for Brand, Brand MPN, Konnra MPN, Compatible Series, KONNRA Product Series, Pitch, Spec and Standard. It answers the question “which of ours do I ask for” and it does not answer the question “will it work”, so both parts of it need stating.
The Molex references it maps cover 5557-02R2 to 06R2, 5557-02R to 24R, 5557-02R-210 to 24R-210, 5559-02P2 to 06P2, 5559-02P3 to 06P3, 5559-02P to 24P, 5559-02P1 to 24P1, 5556T2, 5556T3, 5558T2, 5558T3, 5559-02A4 to 06A4, 5569-02A2 to 24A2, 5566-02A to 24A and 5566-02A2 to 24A2. All rows are marked 4.2mm and “wire to board”, and packaging is described as bagged or boxed.
The four terminal rows are the most useful part of the table, because they are the only rows that carry a material statement:
| Molex reference | KONNRA reference | Description given |
|---|---|---|
| 5556T2 | T4200FBT0102A |
Female terminal, brass, stamp then tin plate, low foot |
| 5556T3 | T4200FBT0104B |
Brass, tin plate then stamp, high foot |
| 5558T2 | T4200MBT0102A |
Male terminal, brass, stamp then tin plate, low foot |
| 5558T3 | T4200MBT0101A |
Brass, tin plate then stamp, high foot |
So the cross-list distinguishes two manufacturing routes — stamp-then-plate, and pre-plated where the strip is tin plated before stamping — and it names brass in all four rows. That is the origin of the material contradiction in this comparison: the specifications leave the base metal open, and the cross-list closes it as brass.
Our part list for the family is published in the specifications, and it is worth reproducing because it is what a purchase order is built from. The housing is H4200M***1601A, and the wafers on the board side are C4200RD1**16T0101PC, C4200RD1**16T0102PC, C4200VD1**16T0101PC, C4200RD2**16T0101PC, C4200RD2**16T0102PC, C4200VD2**16T010*PC, C4200VD2**16T0103*B and C4200VD2**16T0104*B. The wire-to-board terminal page states compatibility with the 5556T2 and 5556T3 series, which is consistent with our own map.
Two further things about our own coverage are worth a line each. There are roughly 22 KR4200 component pages on our site — single and dual row, wafers straight and right angle with post, hollow needle, and hollow needle with column, male and female housings single and dual row with wings, and male and female terminals in wire-to-board and wire-to-wire versions. And the terminal page links both a Product Drawing and the series drawing KR4200-Series-Drawing_WTB.pdf, alongside a wire-to-wire series drawing.
What the map cannot do is qualify a substitution, and that is a structural limitation rather than an oversight in one cell. The Standard column reads RoHS/REACH on every row, which is a materials directive rather than an approval mark, and the table has no voltage, current, temperature, wire range or insulation diameter column at all. A designer needs those five fields to move a part number from one drawing to another, and this article has had to reconstruct all five from specification documents rather than read them from the cross-reference.
Applications Where the 4.2mm Pattern Is Used
Both documents describe this pattern’s applications in terms of conditions rather than industries, and the conditions are the useful part.
It is an internal power-and-signal crimp interface rather than a user-facing port, and the published data says so: a 4.20mm pitch with currents from 1A to 9A, a 30 cycle durability rating at 10 cycles per minute, a crimp set on an applicator, and a panel-mount housing range with a latch.
The board side is chosen first. Where the harness plugs onto a board, the board half is a straight header (5566, 172447, 172647) or a right angle header (5569, 172448, 172648); where two harness halves mate in mid-air, both ends are crimped — female terminal 5556 in housing 5557 against male terminal 5558 in housing 5559.
And the original hands the thermal evaluation back to the application, twice: “PCB trace design may greatly affect temperature rise results in Wire-to-Board Applications” and “Current rating is application dependent… Each application should be evaluated by the end user”, with its figures called “the MAXIMUM current carrying capacity of a fully loaded connector with all circuits powered using tinned copper conductor stranded wire per Molex test method based on a 30º C maximum temperature rise over ambient temperature” and provided “as a guideline”. Where the original says evaluate it, our tier figure is a single number with no test basis attached — and where an application’s safety file specifies glow wire, our documentation stops, because the original names eight glow-capable series to IEC 60695-2-11 and IEC 60335-1 750°C / 2 s and we publish no glow-wire data.
Harness and assembly options
This is the part of the range that is ours rather than a cross-reference, and it is where the two tiers’ practical differences land.
KONNRA supplies the KR4200 series as individual components, crimped housing assemblies or complete wire harnesses, with customisation for application-specific requirements. Complete connector set samples are available within 45 days. Connector production lead time is typically 2 to 4 weeks, and wiring harness lead time is typically 3 to 4 weeks.
On the assembly side, the three settings a harness shop needs are all published for the 5A tier: conductor crimp heights of 1.05 / 1.00 / 0.87 ± 0.05mm for 20 / 22 / 24 AWG, insulation crimp heights of 1.65 / 1.55 / 1.45mm maximum with an insulation crimp width of 2.30mm maximum, and a stripping length of 2.6 to 3.2mm, with crimp strengths of 6.80 / 4.54 / 3.63 kgf minimum. The 9A tier uses different terminal part numbers, so a line that runs both tiers needs two applicator settings and two sets of crimp specifications.
And the strain relief around the connector is specified on the original’s side and not on ours: a minimum free length “T” between the cable tie or wire twist and the connector, from 12.7mm at 2 to 6 dual row to 44.45mm at 22 to 24 dual row. That table is a bench instruction, and its absence on our side means a harness drawing has to carry the figure from another source or from testing.
Sourcing: What Procurement Teams Ask
Four questions come up in almost every enquiry on this family, and all four are answerable from a document rather than from a negotiation.
Which tier, and therefore which terminal. A purchase order that says “KR4200” does not identify a product. It needs the tier — the 5A (20AWG) tier of PS-KR4200-01 / PS-KR4200-03, or the 9A (16AWG) tier of PS-KR4200-02 / PS-KR4200-04 — and the terminal part number that goes with it, because the tiers use different terminals and therefore different crimp tooling.
Which metal, in writing, and from which document. The specifications say Phosphor Bronze/Brass; the cross-list says brass on all four terminal rows. A material declaration should be issued from the controlling specification or the drawing, not from the cross-reference page, and it should name one metal.
Which approval file applies. Our component pages publish UL E482542. The original publishes UL E29179, CSA LR 19980 and IEC 61984, plus a per-series table showing UL(600V), CSA(600V) and IEC(250V). If an approval file references CSA or IEC coverage, that is a gap to close with us rather than a feature to assume.
Lead time and sample timing. Our cross-reference describes packaging as bagged or boxed. Samples within 45 days, connector production typically 2 to 4 weeks, wiring harness typically 3 to 4 weeks. For this family, put the tier, the terminal part number, the conductor, the insulation diameter and the metal in the enquiry, because those five fields are where the comparison is actually decided.
The Five Questions I Would Ask Us, In This Order
If I were buying this cross-reference from KONNRA rather than selling it, these are the five questions I would ask, in this order, and every one of them is a document request rather than an assertion about either company.
- Which tier is on the quotation, and which terminal goes with it? Name PS-KR4200-01 or -03 (5A, 20# to 24#, 1.10 to 1.80mm) or PS-KR4200-02 or -04 (9A, 16# to 20#, 3.10mm Max.), and give the terminal reference —
T4200F*T0102AorT4200FB***01Bon the wire-to-board side, with T4200MBT0102A or T4200MBT0101A as the mating half. - Which base metal is the terminal, in writing, and what is the temperature ceiling that metal carries? Our specification lists Phosphor Bronze/Brass and our cross-list says brass four times. The original rates brass to +80°C and phosphor bronze to +105°C.
- What is the dielectric withstanding voltage as tested on this part number, and is 1,500V a family convention or derived from the 600V rating? The original publishes 2,200V AC for one minute, which is its own 2 × 600 + 1000 formula at 600V, and 1,500V in its older variant document.
- Which wire window applies, and which insulation diameter the wire actually has. Reconcile 20# to 24# with 1.10 to 1.80mm, 16# to 20# with 3.10mm Max., and the terminal page’s 18# to 22# with 2.50mm, against the specific conductor on the drawing.
- What is the current at our gauge, with the test basis, and what does the dual-row table say? Our tier figures are 5A (20AWG) and 9A (16AWG); the original publishes a grid in which 20 AWG is 7A brass and 6A phosphor bronze and 16 to 18 AWG tops out at 9A brass and 8A phosphor bronze.
Engineer’s Pre-Release Checklist
Nine checks, in the order the failures actually happen.
- Tier first, then everything else. Put the tier and the terminal part number on the drawing before any other field, because the wire window, the insulation window and the crimp settings all follow from the terminal rather than from the family.
- Terminal material, in writing. Confirm brass or phosphor bronze and reconcile it against the +80°C and +105°C ceilings the original publishes for those two metals. If the answer is brass, our published +105°C exceeds the original’s brass ceiling by 25°C.
- Dielectric row. Our 1,500V AC for one minute against the original’s 2,200V AC for one minute — and note that Molex’s own older document publishes 1,500V on the same family. Get the tested value for your part number.
- Insulation diameter, checked at both ends. The 5A tier is 1.10 to 1.80mm and the 9A tier is 3.10mm Max.; the original’s 18 to 24 AWG window is 3.10mm maximum. A 20 AWG wire with 2.5mm of insulation passes the original and fails the 5A tier’s ceiling.
- Wire range coverage. We publish no 26 or 28 AWG tier. The original goes to 28 AWG with published currents of 2A brass and 1A phosphor bronze at 28 AWG. If the harness uses fine wire, the answer is a coverage question.
- Current at your conductor, not at the tier label. 5A is our figure for both tiers’ nominal gauges on the low tier and 9A on the high tier; the original’s cells are 9A / 8A at 16 to 18 AWG in 2 to 3 circuits, 7A / 6A at 20 AWG, and 5A / 4A at 22 AWG. Ask for the derating basis.
- Crimp settings and the stripper. Conductor crimp height 1.05 / 1.00 / 0.87 ± 0.05mm at 20 / 22 / 24 AWG, insulation crimp 1.65 / 1.55 / 1.45mm maximum, stripping length 2.6 to 3.2mm, crimp strength 6.80 / 4.54 / 3.63 kgf minimum. A second tier means a second setting.
- Life and forces. 30 cycles at 10 cycles per minute with 20 milliohms maximum change; 14.71 N per circuit maximum insertion against the original’s 14.7 N; 0.98 N per circuit minimum withdrawal at first mate against the original’s 0.5 N, decaying to a lower thirtieth-cycle figure. Read the ladder, not its top rung.
- Approvals, glow wire and post-humidity. Our UL E482542 against UL E29179 / CSA LR 19980 / IEC 61984; no glow-wire data on our side where the original names eight glow-capable series to IEC 60695-2-11 and IEC 60335-1 750°C / 2 s; and our post-humidity insulation resistance of 100 megohms minimum against the original’s general 1000 megohms minimum.
Frequently Asked Questions
What is a Molex Mini-Fit Jr. connector?
It is a 4.20mm (.165 inch) pitch crimp family for wire-to-board and wire-to-wire use, terminated with 16 to 28 AWG stranded copper wire and available with tin or 30µ” gold plating. The wire half is female terminal 5556 in housing 5557, or male terminal 5558 in housing 5559; the board half is the vertical header 5566 or the right angle header 5569. Molex rates it 600V AC/DC and publishes a 56-cell current table whose highest figure is 9A.
What is the KONNRA KR4200?
Our 4.20mm pitch crimp series for the same two interfaces, covering housings, straight and right angle wafers, and both male and female crimp terminals. It is documented in four specifications, all Edition A1 dated 2022/2/26, two per interface, in a 5A (20AWG) tier and a 9A (16AWG) tier, with 600V AC/DC and −40 to +105°C in all four. Our cross-reference maps it against the Molex 5556, 5557, 5558, 5559, 5566 and 5569 series.
Is the KR4200 a drop-in replacement for the Molex Mini-Fit Jr.?
On the electrical level rows and the mechanical forces, it lines up well: contact resistance 10 milliohms, insulation resistance 1000 megohms at 500V DC, durability 30 cycles with 20 milliohms maximum change, temperature rise 30°C, heat resistance 96 hours at 105 ± 2°C, and a per-circuit insertion maximum within 0.01 N of the original’s. Three rows do not line up: the dielectric test level, at 1,500V against 2,200V; the temperature ceiling, which is one figure for a terminal whose metal is left open; and 20 AWG, where our 5A sits below the original’s 7A brass / 6A phosphor bronze.
Is the KR4200 a 5A connector or a 9A connector?
Both, in different documents. PS-KR4200-01 and -03 publish 5A (20AWG) over 20# to 24# with insulation 1.10 to 1.80mm; PS-KR4200-02 and -04 publish 9A (16AWG) over 16# to 20# with insulation 3.10mm Max. The 9A tier is the one that matches the original’s maximum, so a buyer who reads only one file may be buying the lower tier without knowing it exists. Name the tier on the purchase order.
Why is the 9A tier the important one?
Because the original’s own maximum is 9A, at AWG #16 or #18 in a two- or three-circuit brass connector, and our 9A tier publishes the same nominal figure at the same nominal conductor. It also publishes a 3.10mm insulation ceiling, the same figure Molex publishes for its 18 to 24 AWG window. The correspondence lives in the second document on both rows.
What is MX4.2?
The catalogue shorthand used in Asia for the 4.20mm Molex Mini-Fit Jr. pattern — “MX” for Mini-Fit and 4.2 for the 4.20mm pitch. It is not a Molex series number; those are 5556, 5557, 5558, 5559, 5566 and 5569, with further series for glow-capable and panel-mount variants. A requirement that arrives as “MX4.2” fixes the pitch and says nothing about the tier, the metal, the wire window or the circuit count.
What current does the original carry at 20 AWG, and what do we carry?
At 20 AWG in a two- or three-circuit connector, Molex publishes 7A for brass and 6A for phosphor bronze. Our 5A tier publishes 5A at 20 AWG, and our 9A tier’s window includes 20# but states its rating as the tier’s 9A (16AWG) figure rather than as a per-gauge table. At the gauge where both sides publish a figure for the same conductor, our number is 1A to 2A lower.
What is the voltage rating, and are the two companies level?
Both publish 600V AC/DC. The difference is that the original publishes voltage per agency — UL(600V), CSA(600V) and IEC(250V) — so the same family carries two different voltages depending on the standard applied. Our four specifications publish one figure, 600V AC/DC, and our terminal page publishes Operating Voltage (AC/DC) 600V. We are level with the original’s UL and CSA columns and not level with its IEC column.
Why is the dielectric test level different from the original’s?
Molex publishes 2,200 VAC for one minute with leakage under 5 mA — exactly two times its 600V rating plus 1,000 volts (2 × 600 + 1000 = 2200). Our four specifications publish 1500V AC for one minute, so we are 700V below what the formula yields. It is a house figure: the same 1,500V appears in our 250V-rated 3.00mm, 3.96mm wire-to-board and 3.96mm board-in specifications. Request the tested value for your part number rather than deriving it.
What is the operating temperature range?
We publish −40 to +105°C in all four specifications, and our terminal page publishes −40°C to 105°C. The original publishes two ranges, split by base metal: brass terminals −40 to +80°C, phosphor bronze terminals −40 to +105°C, with the footnote “Including 30°C terminal temperature at rated current”. If the terminal is brass our +105°C exceeds the original’s brass ceiling by 25°C; if it is phosphor bronze the figures match. Our specification lists Phosphor Bronze/Brass and our cross-list says brass on every terminal row.
What wire gauges and insulation diameters are supported?
On the 5A tier, 20# to 24# with insulation 1.10 to 1.80mm; on the 9A tier, 16# to 20# with insulation 3.10mm Max.; the terminal page adds 18# to 22# with 2.50mm. The original publishes 16 to 28 AWG across three windows: 3.15mm at 16 AWG, 3.10mm at 18 to 24 AWG and 1.80mm at 22 to 28 AWG. No 26 or 28 AWG exists on either of our tiers, and the 5A tier’s 1.80mm ceiling is 1.30mm tighter than the original’s 3.10mm for 18 to 24 AWG.
What are the mating forces per circuit?
The original specifies 14.7 N maximum insertion and 0.5 N minimum withdrawal per circuit at 25 ± 6 mm per minute with the latch disabled. Our §8.0 single-row table divides to 1.50 kgf per circuit maximum insertion — 14.71 N — and 0.10 kgf per circuit minimum withdrawal at first mate, which is 0.98 N, with a lower figure at the thirtieth cycle. The insertion maxima agree to within 0.01 N per circuit, and our withdrawal floor is about double the original’s.
What are the contact resistance and insulation resistance?
Both exact matches. Contact resistance is 10 milliohms maximum on both sides, and our §5.1 names the same basis — a dry circuit at 20mV and 100mA per EIA-364-23C — as the original’s 20 mV maximum and 100 mA with wire resistance removed. Insulation resistance is 1000 megohms minimum at 500V DC on both sides, our clause specifying 500V DC for one minute between adjacent contacts per EIA-364-21B. The departure is post-humidity: our §7.7 requires 100 megohms minimum, against the original’s general 1000 megohms.
How many mating cycles does it survive?
30 cycles on both sides, at a maximum rate of 10 cycles per minute, with a maximum change in contact resistance of 20 milliohms from initial. The original’s clause names the interfaces the figure is based on — 30µ” gold or 50µ” tin at the contact interface — so its rating is plating-specific. A 30 cycle life is an assembly and service rating rather than a user-mating rating.
What certifications does each carry?
Our component pages publish UL E482542. The original publishes UL File E29179, CSA Certificate LR 19980 and IEC 61984 tested with an NRTL type-examination certificate on request, plus the per-series UL(600V) / CSA(600V) / IEC(250V) table. It also names eight glow-capable series tested to EN 60695-2-11 / IEC 60695-2-11 with an EN 60335-1 / IEC 60335-1 750°C, 2 second, no flaming investigation, and we publish no glow-wire data.
Does the KR4200 come in wire-to-wire as well as wire-to-board?
Yes, documented separately for each. PS-KR4200-01 and -02 cover wire-to-board; PS-KR4200-03 and -04 cover wire-to-wire, and the wire-to-wire documents add a male terminal — T4200MBT0102A on the 5A tier and T4200MBT0101A on the 9A tier. All four publish the same 600V AC/DC and the same −40 to +105°C, so the interface changes the terminal list and the tier changes the current and wire windows.
How long do samples and production take?
Complete connector set samples within 45 days. Connector production lead time is typically 2 to 4 weeks, and wiring harness lead time is typically 3 to 4 weeks. For this family, include the tier, the terminal part number, the conductor, the insulation diameter and the terminal base metal in the enquiry. Those fields decide the comparison, and four of them cannot be answered from the cross-reference page.
Start Your Cross-Reference Check
KONNRA supplies the KR4200 series as individual components, crimped housing assemblies or complete wire harnesses, with customisation for application-specific requirements.
- Request a quote — KR4200 pricing, MOQ and configuration for your circuit count and wire
- Request a sample — complete connector set samples within 45 days
- Request cross-reference verification — confirm KR4200 equivalence against your specific Molex reference
- Name the tier on the request — the 5A (20AWG) tier of PS-KR4200-01 / -03 or the 9A (16AWG) tier of PS-KR4200-02 / -04, with the terminal part number that goes with it
- Request the terminal base metal in writing — brass or phosphor bronze, reconciled against the original’s +80°C and +105°C ceilings and against the cross-list’s brass claim
- Request the dielectric test level for your part number — whether our 1,500V AC is a family convention or derived from the 600V rating
- Request the wire and insulation windows reconciled — 20# to 24# with 1.10 to 1.80mm, 16# to 20# with 3.10mm Max., and the terminal page’s 18# to 22# with 2.50mm
- Request the current derating basis and the dual-row table — our tiers publish one figure each and §8.0 states that a dual-row table follows in the same clause
- Request coverage for 26 and 28 AWG — neither tier reaches the fine end, where the original publishes 2A and 1A figures
- Request a material declaration, the post-humidity insulation resistance and the agency statement — from the controlling document, with our 100 megohms minimum against 1000 megohms minimum, and our UL E482542 against UL E29179 / CSA LR 19980 / IEC 61984
- Request the glow-wire, wave solder and strain relief positions — the original’s eight glow-capable series, its plating-dependent solder maxima and its 12.7mm to 44.45mm cable-tie table have no counterpart on our side
- Submit a drawing for review — we will flag any specification mismatch before you commit tooling or a board respin
Contact KONNRA Electronics
- Phone: (86)-769-85449875
- Email: info@konnra.com
- Address: No.6 Nanchang South Road, Chijiao, Wangniudun, Dongguan, Guangdong, China
- Contact us
👉 KR4200 cross-reference for the Molex Mini-Fit Jr. 5556/5557/5558/5559 series · KR4200 female terminal, wire-to-board · Wire-to-board connector range · Wire-to-wire connector range
Sources and method. Every figure here is taken from a manufacturer document, and where two documents disagree both figures are printed rather than averaged or reconciled. Two Molex documents were used. The current one is PS-5556-001 REV E8, dated 2016/05/09, 12 sheets, titled PRODUCT SPECIFICATION FOR MINI-FIT JR. CONNECTOR SYSTEM, which supplied the scope statement, both series maps, the agency columns (UL 600V, CSA 600V, IEC 250V), the 600V AC(RMS) or 600V DC rating based on UL 1977, the three applicable-wire windows, the 56-cell maximum-current table and its notes, the temperature ranges split by base metal, the wave-solder temperatures, the glow-wire series list, the electrical, mechanical and environmental clauses, the packaging guidance, the Series 44281 test-plug recommendation and the cable-tie free-length table. The older one is PS-5557-001 REV B, dated 2007/09/25, 9 sheets, titled NEW MINI FIT CONNECTOR WITH FLANGE RIGHT ANGLE, which supplied the variant part numbers 5556APBT(L), 5557-NR, 5557-NR-210, 5569-NB1 and 5569-NB1-210, the 1.3mm to 3.1mm insulation window, the 1500V AC(rms) for one minute dielectric strength, the crimp pull-out forces, the whole-connector insertion and withdrawal table and the salt spray and SO2 clauses. Where those two documents differ — notably 2,200 VAC in the current specification against 1,500V in the older one — both are printed, because both are Molex documents and this article does not choose between them.
Four KONNRA documents were used: PS-KR4200-01, -02, -03 and -04, all Edition A1 and all dated 2022/2/26, at seven, seven, six and six pages, which supplied the tier table, the part-list references, the materials clauses, the electrical clauses, the insertion and withdrawal ladder, the retention and pin forces, the crimp settings, the durability and environmental clauses and the tier-level voltage and temperature statements. The cross-reference page (page 16274) titled “KR4200 equivalent to molex mini-fit jr 5556/5557/5558/5559 series” supplied the mapping rows, the brass designations and the RoHS/REACH Standard column. The component page kr4200-female-terminal-wtb (id 2822) supplied the 9A, 18# to 22#, 2.50mm combination and UL E482542. An existing site article, post 18677, supplied its headings and its statement that dimensional and electrical datasheets are not itemized in the catalog record, alongside a media asset titled “KR4200 4.2mm Pitch 5A current single or dual row connector”. Assets referenced by those pages include KR4200-Series-Drawing_WTB.pdf, KR4200-Series-Drawing_WTW.pdf, KR4200-Series-Female-higt-foot-terminal_5.pdf and roughly 22 KR4200 component pages.
What could not be obtained, stated plainly. No dual-row insertion and withdrawal values, so only the single-row ladder is compared. No normal-force, glow-wire, wave-solder, solderability, mixed-flowing-gas or cyclic-humidity data from KONNRA, and no third-party or NRTL report for the KR4200, so those rows are recorded as gaps rather than as comparisons. No salt spray clause in either the current Molex specification or PS-KR4200-01, so no salt spray comparison is made. No KONNRA housing or wafer dimensions, so no footprint comparison. Where a figure could not be confirmed on both sides, this article says so rather than filling the row.
