JST XH 2.5 Connector Complete Guide: Ratings, Terminals, Tooling and the KONNRA KR2501 Equivalent

Quick answer: The JST XH is a 2.5mm pitch, single-row, wire-to-board crimp connector with a friction lock and a box-shaped shrouded header, rated 3A AC/DC with AWG #22 wire at 250V AC/DC, mating at a 9.8mm assembled board height, and accepting AWG #30 to #22 (0.05mm² to 0.33mm²) with an insulation O.D. of φ0.9mm to φ1.9mm and a 1,000 VAC withstand. The KONNRA KR2501 is documented as its cross-reference equivalent across the housing, the terminal and all four board-side wafers, and that part-number mapping is correct. What differs is the envelope: KONNRA documents a wider temperature range (−40°C to +105°C against JST’s −25°C to +85°C), a narrower wire and insulation window (22#–28# and 1.2–1.8mm against JST’s #30–#22 and φ0.9–1.9mm), and a current rating referenced to a different conductor (24 AWG against JST’s AWG #22). One number on KONNRA’s own product page also contradicts its own specification: the page states a 250V AC/minute withstanding voltage where PS-KR2501-01 section 5.3 states 1,000V AC for one minute — which is JST’s figure.

The connector everyone has met, and the four windows that decide a transfer

The JST XH is the 2.5mm family that ended up on 3D printer mainboards, RC battery leads, appliance control panels and industrial I/O modules. It is not the smallest connector JST makes and it is not the cheapest, but it is the smallest pitch in JST’s crimp range that still carries 3A at 250V behind a positive friction lock and a fully shrouded header. JST states the XH was developed from its NH series, and documents the header as interchangeable with the NR and NRD insulation-displacement connectors and the JQ board-to-board connector — so one PCB footprint can carry three different termination systems.

That is also where the trouble starts. Three JST families share the 2.5mm pitch — XH, EH and XA — and they do not mate with each other. The XH is additionally sold as “2.54mm” across a large part of the trade, which is not the pitch JST specifies. And the family’s wire range gets quoted as three different numbers depending on whether the writer is reading the series, one terminal, or one terminal’s insulation window.

This guide is built the other way round from a marketing page. Every JST figure below comes from JST’s published XH documentation, every KONNRA figure from KONNRA’s published product and specification documents, and every disagreement is stated rather than averaged. The point of the exercise is not to prove the parts are identical. It is to hand an engineer the short list of things to check before a cross-reference goes into a released drawing.

A note on naming: this part appears as JST XH 2.5 connector, JST XH2.5, XH 2.5mm, XH2.54, “2.5mm JST connector” and “2.54mm JST connector” in listings and searches. The connector JST documents as the XH runs at a 2.5mm pitch. This guide also cross-references the KONNRA KR2501 series, which KONNRA documents as the XH 2.5 equivalent.

What this guide covers:

• The verified JST XH specification, and KONNRA’s KR2501 specification, side by side
• The part-number cross-reference, component by component
• The four windows — insulation, conductor, temperature and current basis — that decide whether a design transfers
• The one row where KONNRA’s product page and its own specification disagree
• Material and plating callouts across three KONNRA documents
• The full mechanical, crimp, environmental and soldering data from PS-KR2501-01
• DIP versus SMT, the 2.5mm pitch class, and the 2.5mm-versus-2.54mm question
• Sourcing questions procurement teams ask, and how to get a cross-reference check

Key Specifications at a Glance

Attribute	JST XH	KONNRA KR2501
Pitch	2.5mm	2.5mm
Configuration	Single row, wire-to-board, crimp	Single row, wire-to-board, crimp
Lock	Friction lock	Friction lock (documented as “with lock”)
Header style	Box-shaped shrouded header; boss version available	Shrouded wafer, straight and right-angle
Mating direction	Top entry, side entry	Straight (180°), right-angle (90°)
Mounting	Through-hole and SMT (SMT catalogued for 3, 4 and 6 circuits only)	DIP and SMT, straight and right-angle
Assembled board height	9.8mm	9.8mm
Current rating	3A AC/DC with AWG #22	3A with 24 AWG
Voltage rating	250V AC/DC	250V AC/DC
Temperature range	−25°C to +85°C (including temperature rise under load)	−40°C to +105°C
Conductor size	AWG #30 to #22 (0.05mm² to 0.33mm²)	22# to 28#
Insulation O.D.	φ0.9mm to φ1.9mm (terminal-dependent)	1.2mm to 1.8mm
Contact resistance	Not published on the series page; the catalogue gives a separate initial limit and post-environmental-test limit	20mΩ max, single figure
Insulation resistance	1,000MΩ min.	1,000MΩ min.
Withstanding voltage	1,000 VAC for one minute, no breakdown or flashover	1,000V AC for one minute per specification §5.3; the product page states 250V AC/minute
Housing material	PA 6, UL94V-0, natural (white)	PA66 UL94 V-0 per specification §3.0; “PBT, UL94 V-0” on the housing page
Header / wafer material	Post: brass, copper-undercoated, tin-plated (reflow treated). Wafer: PA 66 natural (white); glass-filled PA 66 on the -2 type; PA 6T on the SMT type	DIP base PA66 UL94 V-0; SMT base LCP or PA9T UL94 V-0; contact brass, tin or gold over nickel
Plating	Tin-plated with reflow treatment; gold-plated products on request	Tin over nickel; specification §3.0 also allows gold over nickel
Terminals	Three: SXH-001T-P0.6, SXH-001T-P0.6N (low insertion force) and SXH-002T-P0.6	One terminal part number, T25010PT0101F
Circuits	1, 2, 3, …, 16 and 20	2 to 16
Crimp tooling published	Crimp machines and applicators named for each contact	Crimp dimensions published; no applicator part numbers
3D / 2D data	IGES, STEP, 3D-PDF and 2D-PDF published for every housing and header	Series drawing and specification PDFs
Agency	CSA, TÜV, UL	UL E482542

Both columns are compiled from manufacturer documentation. Sources are listed at the end of this guide.

What the JST XH 2.5 Connector Actually Is

KONNRA KR2501 series XH 2.5 wire-to-board connector with friction lock, the cross-reference for the JST XH 2.5

A complete connection uses three parts:

• XHP housing — the wire-side plug, catalogued from 1 to 16 circuits and 20
• B…B-XH or S…B-XH header — the PCB-side shrouded header, top entry or side entry, through-hole; …-XH-SM4-TB for surface mount
• SXH terminal — the crimp contact, selected by wire size and insulation diameter

JST’s own description of the family, in its catalogue wording:

• “Original double-leaf contact design” — the terminal uses a folded double-leaf contact rather than a simple cantilever
• “Box-shaped shrouded header” — the header is fully boxed, so the contacts are protected and the mating housing is guided in
• “Header is also available with boss” — a locating-boss version exists for placement and mechanical location
• “The pin version conforms to JEMA’s Home Automation (HA) terminal standards” — a conformance claim JST makes for the pin version of the header
• Developed from the NH series — JST states the XH was developed based on the reliability of its NH connectors
• Compatible IDC-style connector available (NR, NRD) — the header also accepts insulation-displacement termination
• Radial taping — headers are available on radial tape for automatic insertion, in addition to the standard packaging

The pin count, the shrouded box and the friction lock are the three features that explain why this family survives in markets where cheaper connectors exist. The box protects the contacts from a misaligned cable, and the friction lock means the housing does not walk out of the header under vibration — which is the actual failure mode on a printer or an appliance harness.

The Cross-Reference, Component by Component

KONNRA’s KR2501 documents six components, and all six name the JST XH as the reference. The mapping is:

KONNRA component	KONNRA part number	JST XH equivalent	JST document
Housing	H250101**0101G	XHP-1 … XHP-16, XHP-20	Housing table, JST XH catalogue
Terminal	T25010PT0101F	SXH-001T-P0.6 / SXH-001T-P0.6N / SXH-002T-P0.6	Terminal table, JST XH catalogue
DIP straight wafer (180°)	C2501VD1**01T010*P*	B…B-XH-A (top entry), B…B-XH-AM (with boss)	Top-entry header table
DIP right-angle wafer (90°)	C2501RD1**01T010*P*	S…B-XH-A (side entry), S…B-XH-A-1 (7.6mm variant)	Side-entry header table
SMT straight wafer (180°)	C2501VS1****M01**RA	S…B-XH-SM4-TB (SMT, 3, 4 and 6 circuits)	SMT header table
SMT right-angle wafer (90°)	C2501RS1****M01**RA	S…B-XH-SM4-TB (SMT, 3, 4 and 6 circuits)	SMT header table

Two things are worth saying about this table.

First, the reference is correct. Unlike some 2.5mm cross-references on the market, this one is not pointing at a neighbouring family. KONNRA’s housing page, terminal page and all four wafer pages each carry Compatible: XH Series, and the JST XH is a real, currently catalogued series with a published specification. That is the baseline an engineer needs, and it is met.

Second, it is a one-to-many mapping in both directions, and that is where the work is. KONNRA documents one terminal part number for the whole wire range, where JST splits the same series across three terminals. On the board side it is the reverse: KONNRA catalogs four wafer types covering 2 to 16 circuits, where JST catalogues through-hole headers from 2 to 16 and 20 circuits but lists surface mount for 3, 4 and 6 circuits only.

That asymmetry is the reason this guide spends its length on windows rather than on headline numbers. The headline numbers agree. The windows do not.

The Four Windows That Decide a Transfer

This is the part of the comparison that decides whether a dropped-in KR2501 behaves like the XH it replaced.

Window 1 — Insulation outside diameter

Source	Insulation O.D. window
JST XH, series level	φ0.9mm to φ1.9mm
JST XH, note	Terminal-dependent — the window is split across the three SXH terminals
KONNRA KR2501, specification §4.0	1.2 to 1.8mm
KONNRA KR2501, product page General Specification	1.2mm to 1.8mm
KONNRA KR2501, terminal component page	1.2 – 1.8mm

KONNRA’s window sits inside JST’s and is narrower at both ends. A harness built on wire with a 1.8mm to 1.9mm insulation diameter is inside the original specification and outside the replacement’s. At the other end, wire from 0.9mm to 1.2mm is likewise inside JST’s stated window and outside KONNRA’s.

This is the highest-risk item in the whole comparison because it fails quietly. A conductor that is too thick for the insulation barrel does not produce a no-fit; it produces a crimp that closes on the insulation instead of gripping it, and the joint passes a continuity check and fails in the field. On a 2.5mm connector, where the insulation barrel has to fit inside the housing cavity, the insulation diameter is a design input and not a manufacturing detail.

What to do: measure the actual insulation O.D. of the wire callout on the harness drawing, not the nominal. Then confirm it in writing against the terminal you are quoting.

Window 2 — Conductor range

Source	Applicable conductor
JST XH, series level	AWG #30, #28, #26, #24, #22 (0.05mm² to 0.33mm²)
KONNRA KR2501, specification §4.0	AWG 22# to 28#
KONNRA KR2501, all component pages	22#–28#

The heavy end matches: both accept AWG #22, which is also the conductor at which JST rates the full 3A. The light end does not: AWG #30 and #29 are inside JST’s range and outside KONNRA’s.

That matters more than it looks. On a signal run the fine gauges are the ones a designer reaches for when the harness has to snake through a hinge or a cable chain, and AWG #30 is the gauge the series range starts at. If your harness is already built on #30, the KR2501 as documented is not a drop-in for it — it is a wire change plus a connector change.

Window 3 — Operating temperature

Source	Temperature range
JST XH, series level	−25°C to +85°C
JST note	“including temperature rise in applying electrical current”
KONNRA KR2501, specification §4.0	−40°C to +105°C
KONNRA KR2501, all component pages	−40℃ to 105℃

This one runs the other way, and it is the claim an engineer should look at hardest.

KONNRA’s documented range is 20°C wider at the hot end and 15°C wider at the cold end than the original’s. It is also identical to the range KONNRA publishes for several other 2.5mm and 2.0mm series, which is what you would expect from a house specification rather than from a part-specific qualification.

None of that means the KR2501 cannot run at +105°C. It means the figure is KONNRA’s own, and a designer who needs +105°C should ask for the evidence behind it — the material’s continuous service temperature, the heat-ageing data, and the temperature-rise test result at the current the application actually draws. JST’s own note is instructive here: its −25°C to +85°C is stated as including the temperature rise under load, which is the conservative way to publish a range and also the reason it is narrower.

What to do: if the application sits above +85°C or below −25°C, treat the KONNRA figure as a claim to be supported rather than a specification to be assumed. The supporting test is PS-KR2501-01 §7.5 (heat resistance, 105±2°C for 96 hours) and §7.2 (temperature rise, 30°C max) — ask for the reports.

Window 4 — What the current rating is referenced to

Source	Current rating and reference conductor
JST XH, series level	3A AC/DC (AWG #22)
KONNRA KR2501, specification §4.0	3A (24AWG)
KONNRA KR2501, all component pages	3A, with wire size listed separately as 22#–28#

The two manufacturers publish the same number and reference it to a different conductor — JST rates 3A with the heaviest wire in its range, KONNRA rates 3A with the second-lightest.

The same 3A, referenced to a thinner conductor, is not automatically a problem: a rating quoted on 24 AWG is the more cautious of the two, because a heavier conductor is thermally better and the limit is being set by the contact rather than by the wire. But it does mean the two 3A figures are not the same statement, and a design that was qualified on the JST number cannot simply inherit it. If your application runs the connector at or near 3A, ask for the KR2501’s carried-current and temperature-rise result at AWG #22, not at 24 AWG.

Where the Two Documents Agree

The overlap covers most of what a design gates on, and it is worth listing explicitly because it is the reason the cross-reference is workable at all:

• Pitch — 2.5mm. JST dimensions the through-hole layout at 2.5 ±0.05mm between contact centres; KONNRA documents 2.50mm.
• Assembled board height — 9.8mm on both sides, so enclosure clearance does not change when you cross-reference.
• Rated voltage — 250V AC/DC on both sides.
• Insulation resistance — 1,000MΩ min. on both sides.
• Withstanding voltage — 1,000V AC for one minute. JST states “no breakdown or flashover while applying 1,000 VAC for one minute”; PS-KR2501-01 §5.3 states “apply 1000V AC for 1 minute between adjacent terminal or ground”, with the same requirement, based on EIA-364-20A.
• Contact resistance — 20mΩ, with a caveat on how it is published (see below).
• Lock — friction, with a polarised housing that seats in one orientation only.
• Row count — single.
• Voltage rating applied AC and DC on both sides.
• Base metal — phosphor bronze on the terminal on both sides.

The 1,000V withstanding voltage is the most useful agreement on this list. It is the figure that most often gets mangled in cross-references, and here the two manufacturers’ specifications state the same test: 1,000V AC applied for one minute between adjacent terminals or to ground, no breakdown and no flashover.

Which brings us to the one number on KONNRA’s own product page that does not match its own specification.

The Withstanding Voltage Row: the Page and the Specification Disagree

The withstanding voltage is the parameter most often mis-stated in cross-reference work, so it is worth showing all four places the number appears.

Document	What it states
JST XH series page	“There shall be no breakdown or flashover while applying 1,000 VAC for one minute.”
KONNRA specification, section 5.3	“Mate connectors, apply 1000V AC for 1 minute between adjacent terminal or ground… No Breakdown and Flashover” (based upon EIA-364-20A)
KONNRA product page, General Specification table	Withstanding Voltage: 250V AC/ minute
KONNRA product page, Overview prose	“…also have excellent voltage resistance, withstanding 250 V AC without stress in just one minute.”

The specification and the original agree. The product page does not agree with either — it carries the rated voltage, 250V, in the dielectric strength row, and the error then propagates into the marketing paragraph underneath, which repeats it as if it were a performance result.

Two of KONNRA’s pages carry this: the main KR2501 product page and the second KR2501 page that sits at a different URL (/product/kr2501-series-xh-2-54-wire-to-board-connector-with-lock/). Both publish the identical General Specification block.

What this means practically. Nothing is wrong with the product. PS-KR2501-01 §5.3 puts the KR2501 at the same 1,000V AC withstand as the JST XH, tested the same way, cited to the same EIA-364-20A method. What is wrong is the published figure, and a published figure is what a design reviewer reads. An engineer comparing the two product pages will see a four-fold shortfall that does not exist, and either reject the part or spend a week chasing a clarification.

If you are evaluating the KR2501 against a specification that calls out dielectric strength, work from PS-KR2501-01 §5.3 and treat the 250V row on the product page as a documentation defect. It is on our own correction list, and the specification is the controlling document.

Materials and Plating: Three Callouts for One Part

Materials are where a cross-reference either earns confidence or loses it, because the resin grade decides the reflow profile, the dimensional stability and the flammability rating. KONNRA publishes the KR2501’s materials in three places, and they do not say the same thing.

Item	PS-KR2501-01 §3.0	KR2501 component pages	KR2501 product page	JST XH
Housing resin	PA66 UL94 V-0	PBT, UL94 V-0 (housing page)	PA9T/LCP/UL94/Brass (one “Material” row)	PA 6, UL94V-0, natural (white)
Terminal base metal	Phosphor bronze	—	Brass (from the same single “Material” row)	Phosphor bronze
Terminal plating	Tin plated over nickel	Tin over Nickel	Tin over Nickel	Tin-plated, reflow treated; gold on request
DIP wafer base	PA66 UL94 V-0	PA66, UL94 V-0	—	PA 66, natural (white)
SMT wafer base	LCP or PA9T UL94 V-0	PA9T, LCP, UL94 V-0	—	PA 6T, natural (ivory)
Wafer contact	Brass, matte-tin or gold plated over nickel	Brass, Tin over Nickel	Brass, Tin over Nickel	Brass, copper-undercoated, tin-plated
Solder tab	Brass, matte-tin plated over nickel	—	—	Brass, copper-undercoated, tin-plated
Colour	—	Housing White; DIP wafers White; SMT wafers Beige	—	Housing natural (white) plus 8 further colours; header natural (white) or ivory plus 8

Three things fall out of this table.

The housing resin is stated three ways across one supplier’s own documents. The specification says PA66, the housing component page says PBT, and the product page’s single “Material” row says PA9T/LCP — which reads as the wafer materials being merged into the housing row, because PA9T and LCP are the SMT wafer bases. PA66, PBT and PA9T are different polymers with different moisture uptake, different reflow tolerance and different cost. The specification is the document to pin this to, and it should be reconciled with the page.

The terminal base metal agrees with the original. Both sides specify phosphor bronze for the terminal — the one material callout where the two manufacturers match exactly, and the one that matters most for contact spring behaviour.

Gold over nickel is a documented option that the pages do not surface. PS-KR2501-01 §3.0 allows the wafer contact to be “Matte-Tin or Gold Plated Over Nickel“. The product page states flatly “Product Plating: Tin over Nickel”, with no mention of the gold option. JST’s equivalent position is that XH contacts are tin-plated with reflow treatment, with gold-plated products available on request. So the two suppliers actually offer the same choice; only one of them says so on the page. If your design needs gold — for low-level signal stability, for a corrosive atmosphere, or for a supplier agreement that calls it out — specify it explicitly rather than reading it off the product page.

KONNRA KR2501 2.50mm pitch wire housing with friction lock

➡️ KR2501 Housing

A note on housing colour. JST documents the XH housing in natural (white) plus Black, Red, Blue, Yellow, Lemon yellow, Green, Brown and Fluorescent yellow, and the header in natural (white) or ivory plus the same list, which is how harness builders keep connectors from being swapped on the line. KONNRA documents the KR2501 housing and DIP wafers as White and the SMT wafers as Beige. If colour coding is part of your assembly’s error-proofing, that is a conversation to have at quotation rather than at drawing release.

Terminal Design and Crimping

The JST XH terminal uses what JST calls an “original double-leaf contact design” — a folded contact rather than a single cantilever. JST splits the family across three terminals, and the split matters because the terminal decides the accepted wire, not the series:

JST terminal	Role in the range	JST’s own description
SXH-001T-P0.6	The standard part	Catalogued as the normal type
SXH-001T-P0.6N	For easier mating	Catalogued as the low insertion force type; JST states it is less resistant to the vibration than the standard contact
SXH-002T-P0.6	The fine-wire part	Covers the light end of the series range

KONNRA documents one terminal for the KR2501 — T25010PT0101F — with a single insulation window of 1.2–1.8mm applying across the whole 22#–28# wire range.

The engineering consequence is simple and worth stating plainly. With the JST part, “what wire can I use” has a different answer for each of the three terminal part numbers, and the series range (#30–#22) is the union of them. With the KR2501, there is one answer. A harness drawing that specifies a JST terminal part number and a wire does not translate into a KR2501 drawing by copying the wire across — the wire and the insulation diameter have to be re-checked against the single KR2501 window, and wire at the light end (#30, #29) has no documented home on the KR2501 at all.

KONNRA KR2501 2.50mm pitch crimp terminal for JST XH 2.5 wire-to-board connections

➡️ KR2501 Terminal

Crimp specification

PS-KR2501-01 §6.5 publishes a full crimp table. This is more than most cross-reference sources carry, and it is the table a harness shop actually tooling the connector needs.

Parameter	22 AWG	24 AWG	26 AWG	28 AWG
Conductor crimp width	1.75 ±0.15mm (all four sizes)
Conductor crimp height	0.73 ±0.05	0.67 ±0.05	0.62 ±0.05	0.55 ±0.05
Insulation crimp width	2.05mm max (all four sizes)
Insulation crimp height	1.80 ±0.10	1.70 ±0.10	1.60 ±0.10	1.45 ±0.10
Crimp strength	4.54 kgf min	3.63 kgf min	2.27 kgf min	1.36 kgf min
Stripping length	1.6 – 2.1mm (all four sizes)

Two observations.

The conductor crimp heights run the right way. They decrease as the conductor gets thinner — 0.73mm at 22 AWG down to 0.55mm at 28 AWG — which is the correct direction, and the same is true of the insulation crimp heights, 1.80mm down to 1.45mm. This is worth checking on any crimp table you are handed, because the direction carries the whole meaning and a reversed ladder is easy to publish and hard to notice.

One number deserves reconciliation before a 22 AWG harness is released. The insulation crimp height at 22 AWG is specified as 1.80 ±0.10mm, so the accepted band runs from 1.70mm to 1.90mm. The top of that band is 0.1mm above the 1.8mm ceiling that section 4.0 of the same specification states for applicable wire insulation. An insulation crimp height is a finished barrel dimension and depends on the wire and the die, so this does not by itself prove a defect — but two numbers in the same document that appear not to overlap are exactly the kind of thing an engineer should be told about rather than discover. If your harness uses 22 AWG at or near the top of the insulation range, ask for the intended insulation crimp height for that specific wire.

And one gap. KONNRA publishes the crimp geometry but no applicator or crimp-machine part numbers, where JST names the crimp machines and applicators for each of its three contacts. If you crimp in-house, you will need the applicator specification from us — ask for it with the quote rather than after the first build.

The Mechanical Clauses in PS-KR2501-01

PS-KR2501-01 §6.1 to §6.4 publish four mechanical requirements. They are short, and reading them carefully pays.

Clause	What is measured	Test condition	Requirement
§6.1	Insertion and withdrawal force	Insert and withdraw at 25.4 ±3mm/minute, excluding plastic detents; EIA-364-13D	Refer to §8.0
§6.2	Terminal insertion force	Insert the crimped terminal into the housing	1.0 kgf (9.8 N) max
§6.3	Terminal / housing retention force	Apply axial pull out force at 25.4 ±3mm/minute on the terminal assembled in the housing	2.0 kgf (19.6 N) min
§6.4	Pin–pin retention force	Apply axial push force at 25.4 ±3mm/minute	1.5 kgf (14.7 N) min

§6.4 states a retention test that cannot be run as written. A retention force is the force required to separate two parts, so the test is a pull. §6.4 calls for a push while requiring a minimum — and a push in the mating direction is limited by how hard the parts can be pressed together, not by how well they hold. Read literally, the clause is not a retention test.

The corroborating detail is that this is not a one-off typo. The wording in §6.4 of the KR2501 specification is the same as the wording of §6.4 in KONNRA’s KR2500 specification — the same clause number, the same “Apply axial push force”, the same 1.5 kgf minimum — while both specifications correctly say “pull out” in the terminal-retention clause immediately above it. It reads as wording carried across house specifications, and it has been carried for at least two series.

§6.3 is the clause to design against, and it is the stronger of the two. A terminal-to-housing retention of 2.0 kgf (19.6 N) minimum means the wire can take a 2kg axial pull before the terminal leaves the housing. Set that against §8.0, where the minimum withdrawal force for the whole 2-circuit connector is 0.60 kgf — which is 0.30 kgf per contact, because that figure is for the complete 2-way assembly and not per position. Put the terminal’s grip inside the housing (2.0 kgf) against the housing’s grip on the header (0.30 kgf per contact) and the ratio is roughly 6.7:1, which is what you want it to be: the wire’s grip is far stronger than the connector’s grip, so a tug on the cable unplugs the connector instead of pulling a terminal out of it.

Do not cross-read §6.2 and §8.0. §6.2’s 1.0 kgf maximum is the force to click a crimped terminal into its housing cavity, which is a lance-engagement force. §8.0’s insertion figure is the force to mate the two connector halves, which is the contact-spring force and is larger per contact. They measure different things, and a review that treats the 1.0 kgf cap as the mating limit will conclude the connector fails its own specification.

The insertion and withdrawal force table

PS-KR2501-01 §8.0 gives a per-circuit-count force table in kgf for 2 to 16 circuits. This is the complete table.

Circuits	Insertion force max	Withdrawal force min, initial	Withdrawal force min, after 30 cycles	Circuits	Insertion force max	Withdrawal force min, initial	Withdrawal force min, after 30 cycles
2	3.00	0.60	0.40	10	7.00	2.20	2.00
3	3.50	0.80	0.60	11	7.50	2.40	2.20
4	4.00	1.00	0.80	12	8.00	2.60	2.40
5	4.50	1.20	1.00	13	8.50	2.80	2.60
6	5.00	1.40	1.20	14	9.00	3.00	2.80
7	5.50	1.60	1.40	15	9.50	3.20	3.00
8	6.00	1.80	1.60	16	10.00	3.40	3.20
9	6.50	2.00	1.80

The table is internally consistent to three decimal places, which is the most useful thing that can be said about a force table, because it means the numbers were generated from a model rather than transcribed:

• Insertion force maximum = 2.00 + 0.50 × N kgf — 2 circuits gives 3.00, 16 circuits gives 10.00
• Withdrawal force minimum (initial) = 0.20 + 0.20 × N kgf — 2 circuits gives 0.60, 16 circuits gives 3.40
• Withdrawal force minimum (after 30 cycles) = 0.20 × N kgf — 2 circuits gives 0.40, 16 circuits gives 3.20

All 45 figures in the table reproduce from those three expressions, and every circuit count shows the same 0.20 kgf drop after 30 mating cycles. That consistency is a genuine point in the specification’s favour, and it is worth saying out loud in a document that has the flaws listed elsewhere in this guide.

Two practical readings. The insertion force maximum reaches 10.00 kgf — about 98N — at 16 circuits, which is a real number to hold in mind for a hand-assembled harness and for any operator who has to mate it repeatedly. And the withdrawal ladder rises smoothly with circuit count, with no non-monotonic step, which is the opposite of what you sometimes find in published tables.

One limitation, stated plainly. JST does not publish a series-level insertion and withdrawal force table for the XH, so these figures cannot be reconciled against the original — only checked against themselves, which is what the three expressions above do. If your qualification plan depends on a specific withdrawal force, measure a first article rather than comparing two data sheets that are not drawn on the same basis.

Environmental and Durability Programme

PS-KR2501-01 §7 publishes eleven environmental and durability tests, each with a stated requirement. This is the full list.

Clause	Test	Condition	Requirement
§7.1	Durability	Mated up to 30 cycles at 10 cycles per minute, EIA-364-09C	Contact resistance 40mΩ max
§7.2	Temperature rise	Carrying rated current load, EIA-364-70B	Temperature rise 30°C max
§7.3	Vibration	Amplitude 1.5mm P-P; sweep 10~55~10 Hz in 1 minute; 2 hours in each X, Y and Z axis, EIA-364-28B	No damage; contact resistance 40mΩ max; discontinuity 1 microsecond max
§7.4	Shock	490 m/s² (50g), 3 strokes in each X, Y and Z axis, EIA-364-27B	No damage; contact resistance 40mΩ max; discontinuity 1 microsecond max
§7.5	Heat resistance	105 ±2°C for 96 hours, EIA-364-17B	No damage; contact resistance 40mΩ max
§7.6	Cold resistance	−40 ±2°C for 96 hours, EIA-364-59	No damage; contact resistance 40mΩ max
§7.7	Humidity	40 ±2°C, 90–95% RH, 96 hours, EIA-364-31B	No damage; contact resistance 40mΩ max; dielectric strength must meet §5.3; insulation resistance 100MΩ min
§7.8	Thermal shock	5 cycles of −40°C for 30 min, room temperature 5 min, +105°C for 30 min, room temperature 5 min, EIA-364-32B	No damage; contact resistance 40mΩ max
§7.9	Salt spray	16 hours exposure at 35 ±2°C from a 5 ±1% solution, EIA-364-26B	No damage; contact resistance 40mΩ max
§7.10	Solderability	3 ±0.5 seconds at 245 ±5°C, EIA-364-52	95% of the immersed area must show no voids or pin holes
§7.11	Solder resistance	SMT products per the profile in §9.1, EIA-364-56D; DIP products per §9.2, EIA-364-71B	No damage

Four things in this table are worth a designer’s attention.

The contact-resistance limit doubles after every one of these tests. Section 5.1 sets 20mΩ max on a dry-circuit measurement at 20mV and 100mA. Section 7 then allows 40mΩ max after heat, cold, humidity, thermal shock, salt spray, vibration, shock and 30 mating cycles. A relaxation of the limit after conditioning is normal and correct — the surfaces have oxide on them by then — but the size of the step is the number to know. If your application budgets 20mΩ for the whole service life rather than for the first article, this specification permits twice that after conditioning, and the accelerated tests listed here are the ones that will find it.

Humidity is the only environmental test that tightens the insulation resistance requirement — §7.7 requires 100MΩ min, against the 1,000MΩ min set in §5.2 for a dry part. That is a sensible allowance for absorbed moisture, and it is also the clause that predicts behaviour: a nylon-family housing that has absorbed water is the mechanism behind the change in insertion and withdrawal force that shows up on a humid production floor.

Salt spray runs for 16 hours. That is a moderate exposure and it is the test to revisit if the application is outdoor, marine or wash-down. For scale, the connector specifications published for the Molex Mini-SPOX 2.50mm system call for 48 ±4 hours of the same test — a reminder that “passes salt spray” means nothing without the duration.

Durability is specified at 30 mating cycles. JST does not publish a mating-cycle count for the XH at series level, so the two are not comparable, but 30 cycles is the right order of magnitude for a service connector rather than a production-line one. If your assembly is mated more often than that — a test fixture, or a field-serviceable module — say so, because that is a change of product class rather than a change of tolerance.

Soldering: Reflow for SMT, Wave for DIP

PS-KR2501-01 §9 gives two separate temperature profiles, which matters because the KR2501 spans both mounting technologies and the SMT parts use reflow-capable resin.

§9.1 — SMT infrared reflow

• Peak temperature: 255 +5/−5°C held for 5 to 10 seconds
• A 20 to 40 second band at a minimum of 230°C
• A 90 to 120 second reflow band
• Pre-heat: 150 to 200°C

§9.2 — Wave soldering (DIP)

• Peak temperature: 250°C maximum, held for 3 to 5 seconds
• A 60 to 150 second band at a minimum of 217°C
• A 60 to 180 second total band
• Pre-heat: 150 to 180°C

The specification adds a note that is worth quoting because it is the honest engineering position: “Please check welding conditions by your own devices beforehand. Because the condition changes by the soldering devices, P.C. boards, and so on.”

Two practical notes. The profiles above are summarised from the specification’s profile drawings, and the drawings carry additional time elements that the extracted text does not label unambiguously — take the profile from the drawing, not from this table, when you write your process. And the SMT wafer base is LCP or PA9T per §3.0, which is a reflow-capable choice: the DIP parts use PA66, which is a wave-solder material. Getting those two the wrong way round is a classic way to discover the difference between 255°C and 260°C the expensive way.

Documentation and Change Control

PS-KR2501-01 is a 7-page document, Edition A1, with the same date in its “Date Issued” and “Date Revised” fields — 2022/2/26 — and no revision history table. Its section 10.0 reads, in full:

“Any change or revision for the product specification will not be announced in advance. Please contact our sales representative for the latest information.”

The signature block reads “Written: Arvin · Checked: / · Approved: Min xinhao”, with the checking field left empty.

Against that, JST publishes for the XH:

• A full series catalogue with housing, header, SMT, terminal and taping tables
• IGES, STEP, 3D-PDF and 2D-PDF data for every housing and every header, part number by part number
• Application manuals listed alongside the catalogue for the series
• A product page carrying the series specification and the current catalogue link

Two practical consequences, and neither is about paperwork.

The specification is the controlling document, so pin the revision. Section 10.0’s wording is a statement that you will not be told when the document changes, which is common in this industry and is precisely the reason to quote a revision rather than assume a figure is stable. If your qualification file cites the KR2501, cite PS-KR2501-01 Edition A1 and the section number, and ask for written confirmation that it is still current at the point you release.

The CAD data gap is the one that costs engineering time. An engineer cross-referencing the XH will normally start from JST’s 3D model to check a footprint against the board. There is no equivalent published model for the KR2501. What exists is the series drawing and the specification — and the series drawing is a graphics-based PDF from which no dimension can be extracted by text search. So a footprint check has to be done from the specific drawing for your circuit count and mounting type. Ask us for it, and for a 3D model if your CAD system needs one, rather than trying to parse the series drawing.

Circuit Counts, and the Two Ends of the Range

Source	Circuits available
JST XH housings (XHP-…)	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and 20
JST XH top-entry headers (B…B-XH-A)	1 to 16, and 20
JST XH side-entry headers (S…B-XH-A)	2 to 16
JST XH SMT headers (S…B-XH-SM4-TB)	3, 4 and 6 only
KONNRA KR2501	2 to 16, across housing, terminal and all four wafer types

So the KR2501 matches JST across the 2 to 16 band and does not cover either end of the original’s range: there is no 1-circuit KR2501 and no 20-circuit KR2501.

The 20-circuit omission is the more consequential of the two, because 20 ways is a distinct board layout rather than a pin-count variation, and it is the position where JST’s XH competes with larger-pitch families. The 1-circuit omission is a mechanical-keying part in most designs rather than a signal-carrying one — but JST catalogs it, including a top-entry 1-way with a locating boss (B1B-XH-AM), and that is exactly the kind of part a designer uses to make a connector un-mateable with the wrong cable. If you need either end of the range, that is a conversation at enquiry stage, not an assumption.

The reverse case is SMT. JST catalogs the XH in surface mount only at 3, 4 and 6 circuits — S3B-XH-SM4-TB, S4B-XH-SM4-TB and S6B-XH-SM4-TB, side entry, supplied on embossed tape, 800 pieces per reel. KONNRA documents SMT wafers as straight and right-angle across the 2P~16P range. Above six circuits, KONNRA documents an SMT option where JST does not — which is a genuine advantage of the cross-reference rather than a gap in it, and one worth confirming position-by-position against the drawing before it goes into a layout.

Housing and Header Dimensions

JST publishes a complete dimensional table for the XH housing, headers and SMT header. The dimensions below are JST’s published figures and are the ones to check a footprint against.

Circuits	Housing A	Housing B	Header B (top entry)
2	2.5mm	7.3mm	7.4mm
3	5.0mm	9.8mm	9.9mm
4	7.5mm	12.3mm	12.4mm
5	10.0mm	14.8mm	14.9mm
6	12.5mm	17.3mm	17.4mm
7	15.0mm	19.8mm	19.9mm
8	17.5mm	22.3mm	22.4mm
9	20.0mm	24.8mm	24.9mm
10	22.5mm	27.3mm	27.4mm
12	27.5mm	32.3mm	32.4mm
16	37.5mm	42.3mm	42.4mm
20	47.5mm	52.3mm	52.4mm

There are two checkable relationships in this table, and both are useful for sanity-checking any drawing you are handed.

• The housing A dimension — the distance across the contact field — is (N − 1) × 2.5mm. JST lists XHP-4 at 7.5mm and XHP-16 at 37.5mm, and the formula reproduces both. It is the fastest way to confirm that a housing really is 2.5mm pitch: measure it and divide.
• The header B dimension is the housing A dimension plus 4.9mm, because the shroud adds material at both ends. JST lists the 2-circuit header at 7.4mm against a housing A of 2.5mm, and the 20-circuit header at 52.4mm against 47.5mm.

Three further details from the same tables:

Boss versions do not cover the whole range. JST catalogs the with-boss top-entry header (…-AM) for 1 to 10 circuits and 12 circuits — but there is no boss version at 11, 13, 14, 15, 16 or 20 circuits. If a locating boss is part of your placement strategy, that constraint is easy to miss, because the boss column in a catalogue table reads as “available” until you reach the gap.

Side entry comes in two end-face dimensions. JST’s side-entry header is catalogued with 9.2mm from the end face of the mating part to the post as standard, and with 7.6mm as the …-1 variant, for 2 to 15 circuits. The 1.6mm difference decides whether the connector clears an adjacent component or an enclosure wall, and it is the single most common reason a “matching” right-angle header does not fit a copied layout.

Two partially-filled housing types exist. JST’s housing table includes XHP-2(10.0)-U and XHP-6(5.0)-U, where the figure in parentheses is the pitch and JST’s note explains that the remaining circuits are filled with resin. These are keying and layout parts rather than ordinary housings, and they are the sort of item that a cross-reference table built only on circuit count will silently miss.

Through-Hole or SMT: How to Choose

	Through-hole (DIP)	Surface mount (SMT)
KR2501 components	DIP straight 180°, DIP right-angle 90°	SMT straight 180°, SMT right-angle 90°
JST XH equivalents	B…B-XH-A (top entry), B…B-XH-AM (with boss), S…B-XH-A (side entry), S…B-XH-A-1 (7.6mm end face)	S3B-XH-SM4-TB, S4B-XH-SM4-TB, S6B-XH-SM4-TB
Circuit range in the original	1 to 16, and 20	3, 4 and 6 only
Circuit range on the KR2501	2 to 16	2 to 16, documented
Mechanical strength	Higher — pins pass through the board and are soldered, and the friction lock loads the shroud	Lower — retention is by the solder tab and the joint alone
Board real estate	Needs a hole pattern and clearance on the far side	Occupies pads and a solder tab; frees the far side
Assembly	Separate wave or selective solder operation	Placed and reflowed with the rest of the SMT line
Solder profile	250°C peak max for 3–5 seconds	255°C peak for 5–10 seconds, 230°C minimum for 20–40 seconds
Best for	Cables that are plugged and unplugged, or pulled on	High-volume assembly where every insertion operation costs money

The practical rule. Choose through-hole when the connector will see repeated mating or cable pull, because at this pitch and current rating the friction lock is doing real work and the pins carry the load. Choose SMT when assembly cost and board real estate matter more than mechanical retention, and the cable will be routed and left in place.

Check the far side of the board. A through-hole header needs clearance behind the PCB. In a stacked design that clearance may not exist, which is the most common reason a 2.5mm design ends up surface mount despite a preference for through-hole.

Figure 1 — KONNRA KR2501 DIP straight 180 degree wafer, through-hole top entry

➡️ KR2501 DIP Straight Wafer

Figure 2 — KONNRA KR2501 DIP right-angle 90 degree wafer, through-hole side entry

➡️ KR2501 DIP Right Angle Wafer

Figure 3 — KONNRA KR2501 SMT straight 180 degree wafer, surface mount top entry

➡️ KR2501 SMT Straight Wafer

Figure 4 — KONNRA KR2501 SMT right-angle 90 degree wafer, surface mount side entry

➡️ KR2501 SMT Right Angle Wafer

Full series documentation

• KR2501 series engineering drawing (PDF)
• KR2501 product specification PS-KR2501-01 (PDF)
• KR2501 package specification (PDF)

➡️ Request the drawings for your circuit count and mounting type

The 2.5mm Pitch Class: the XH Is Not the Only Connector at This Pitch

Most engineers who say “JST 2.5” mean the XH. JST catalogues more than one family at this pitch, and the one that gets confused with the XH is the EH series — same pitch, same headline current and voltage, different everything else.

Attribute	JST XH	JST EH
Pitch	2.5mm	2.5mm
Circuits	1 to 16, and 20	2 to 15
Current rating	3A AC/DC (AWG #22)	3A AC/DC (AWG #22)
Voltage rating	250V AC/DC	250V AC/DC
Withstanding voltage	1,000 VAC for one minute	800 VAC for one minute
Temperature range	−25°C to +85°C	−25°C to +85°C
Insulation resistance	1,000MΩ min.	1,000MΩ min.
Conductor size	AWG #30 to #22 (0.05–0.33mm²)	AWG #32 to #22 (0.032–0.33mm²)
Insulation O.D.	φ0.9mm to φ1.9mm	φ0.5mm to φ1.9mm
PC board mounting	Through-hole and SMT	Through-hole only
Assembled height	9.8mm	8.1mm (top entry, 3.8mm thick)
Lock	Friction lock	Friction lock
Terminals	SXH-001T-P0.6, SXH-001T-P0.6N, SXH-002T-P0.6	SEH-001T-P0.6, SEH-001T-P0.6L, SEH-002T-P0.6L, SEH-003T-P0.6L
Housings	XHP-…	EHR-…
Headers	B…B-XH-A, S…B-XH-A, …-XH-SM4-TB	B…B-EH-A, S…B-EH, …-EH-TS, …-EH-TV4
Standards	CSA, TÜV, UL	CSA, TÜV, UL
KONNRA equivalent	KR2501	KR2504

The two numbers that decide it. The EH is the lower-profile connector — 8.1mm assembled height against the XH’s 9.8mm — and it has the lower dielectric withstand, 800V against 1,000V. Everything else about the two families looks the same from a distance, which is exactly why they get quoted interchangeably and then found not to fit. They do not mate, and they do not share a footprint.

There is a third family at this pitch as well: JST’s XA, which KONNRA cross-references with the KR2516. So at 2.5mm, the pitch tells you almost nothing about which connector you are holding. Cross-reference on the part number.

Is the XH 2.5mm or 2.54mm?

2.5mm. JST documents the XH at a 2.5mm pitch, and that figure is the one in the series specification, the housing dimensional table and the header table.

The “2.54mm” label is widespread in the trade because 2.54mm is exactly 0.1 inch, and XH connectors routinely sit on the same boards as 0.1-inch pin headers. They are not the same pitch, and the difference compounds. Running JST’s own housing dimension rule — A = (N − 1) × 2.5mm — a 16-circuit XH housing measures 37.5mm across the contact field. At a 2.54mm pitch the same 16 positions would measure 38.1mm. The gap is 0.6mm, which is enough to miss a hole pattern.

And this is where KONNRA’s own website currently contradicts itself. KONNRA publishes two product pages for the KR2501, at two different URLs:

Page	Page title says	The page’s own parameter table says
/product/kr2501-equivalent-to-jst-xh-2-5-alternatives-connector/	XH 2.5	Pitch 2.5mm
/product/kr2501-series-xh-2-54-wire-to-board-connector-with-lock/	XH 2.54	Pitch 2.5mm

Both pages carry the same specification block, the same component list and the same specification PDF — they are the same product described twice, and one of them carries the trade’s incorrect pitch in its title. If you found the KR2501 through the second page, the figure that applies is 2.5mm, and the specification is the controlling document.

If you are holding a part and want to know which family it is, measure the centre-to-centre distance between adjacent contacts. 1.0mm is SH, 1.25mm is GH, 1.5mm is ZH, 2.0mm is PH, 2.5mm is XH. Then measure the housing across the contact field: for an XH it will be (N − 1) × 2.5mm, so a 4-way measures 7.5mm.

The KONNRA 2.5mm Pitch Range

The KR2501 is one of several 2.5mm series KONNRA publishes. If your original part number is not an XH, the cross-reference probably already exists:

KONNRA series	Cross-referenced to	Circuits	Current	Voltage	Rows	Category
KR2501	JST XH 2.5	2–16	3A	250V	1	Wire-to-Board
KR2500	Molex Mini-SPOX 2.50	2–16	3A	250V	1	Wire-to-Board
KR2502	Yeonho YH 2.5	2–20	3A	250V	1	Wire-to-Board
KR2504	JST EH 2.5	2–16	3A	250V	1	Wire-to-Board
KR2507	JST SM 2.5	2–16	3A	250V	1	Wire-to-Wire
KR2508	JST SCN 2.5	2–15	3A	250V	1	Board-In
KR2511	XHQ 2.5	2–16	3A	250V	1	Wire-to-Board
KR2516	JST XA 2.5	2–15	3A	250V	1	Wire-to-Board
KR2556	MX23A (automotive)	18 / 26 / 34P	3A	1,000V	2	Automotive

Decision rule: compact 3A at 250V with a friction lock and a shrouded header → KR2501. Low profile with a lower withstand requirement, or the EH pattern → KR2504. Wire-to-wire rather than wire-to-board → KR2507. Board-in termination → KR2508. XA-pattern wire-to-board with a TPA → KR2516. Two rows and a 1,000V rating → KR2556.

➡️ Explore the full 2.5mm pitch range · Wire-to-board connector catalogue

Applications Where the XH Pattern Is Used

The XH’s combination — 3A, 250V, a friction lock and a shrouded box — puts it in a specific place in a design: bigger than a signal connector and smaller than a power connector.

Application	Why the XH pattern fits
3D printer mainboards and hot-end wiring	2.5mm tolerates repeated mating during maintenance, and 3A covers heater-cartridge and fan loads
RC and hobby battery wiring	The XH pattern is the de facto standard on LiPo balance leads and receiver packs; 3A/250V covers typical pack wiring
Home appliances	Control board to module wiring at mains-derived low voltage, with a friction lock that survives vibration
Industrial control and network equipment	Board-to-module signal and low-power wiring behind a fully shrouded header
Power tools and motor drives	Vibration resistance from the shroud and the friction lock
Lighting and LED modules	Multi-position power distribution at a pitch that is still hand-serviceable
Medical and instrumentation equipment	A documented, crimp-terminated interface for low-voltage internal wiring

The honest limit is the current. 3A per contact at AWG #22 is the ceiling, and above that the answer is a larger pitch rather than a different connector at 2.5mm. If your load is between 3A and 5A, that is a design change, not a part-number change.

Cable assembly options

KONNRA builds cable assemblies on the KR2501 system in the standard harness configurations:

Cable type	Description	Typical use
Single-headed	Housing on one end, bare wire leads on the other	Pigtail to a header, panel wiring
Same-side-head	Housing on both ends, same orientation	Board-to-board extension, same-direction routing
Reverse-side-head	Housing on both ends, reversed orientation	Board-to-board extension, reversed routing
Adapter cables	KR2501 on one end, another series on the other — XH to PH, XH to 2.54mm DuPont, XH to JST VH	Interfacing a 2.5mm device to a 2.0mm, 2.54mm or 3.96mm board

Adapter and transition cables are one of the most common requirements in the XH world — the classic case being a battery or appliance module terminated in XH that has to plug into a 2.54mm header on a controller board. Those are built to order, and the pitch difference is the whole reason they exist.

Connector lead time is typically 2–3 weeks; wiring harness lead time is typically 3–4 weeks.

➡️ Explore KONNRA wiring harness capabilities

Sourcing the JST XH 2.5: What Procurement Teams Ask

Engineering decides that a connector will work. Procurement decides whether the supply chain around it is safe.

“Can you be a second source without changing our design?” That is what a documented cross-reference is for. The KR2501 is specified against the JST XH at component level — housing, terminal and all four board-side wafers — with a matching 2.5mm pitch, 9.8mm assembled height, friction lock and shrouded header. The four windows in this guide are the caveats, and we confirm equivalence against your specific part number and wire, because circuit count, entry direction, mounting type and insulation diameter each change the answer.

“What are your lead times?” Connector production lead time is typically 2–3 weeks. Wiring harness lead time is typically 3–4 weeks. Key materials are prestocked to shorten cycles.

“How long for samples?” Complete connector set samples can be delivered within 45 days. Where you need to validate crimp quality or a cable assembly before committing, sample harnesses can be supplied from the same process used in production.

“What qualifications do you hold?” KONNRA holds ISO9001, ISO14001, IATF16949, ISO45001:2018 and ISO13485 among its quality systems, together with UL product and operational safety certification — the KR2501 components carry UL file E482542. Automotive-grade series additionally hold LV214 and USCAR-2.

“How do we know the parts match your documentation?” Through a CNAS-accredited laboratory with more than 45 sets of precision testing instruments. Dimensional and electrical verification data are available on request, and where this guide has flagged a difference between two KONNRA documents, the same laboratory can be asked to settle it on a first article.

“Are you a manufacturer or a trader?” A manufacturer. Dongguan Konnra Electronics Co., Ltd., founded 2004, with in-house mould design, injection moulding, stamping, assembly and inspection — which is why the connector and the cable assembly can come from one quality system.

“What volumes can you support?” KONNRA reports four production bases with automation coverage above 95%, and a product mix split roughly 60% connectors and 40% wiring harnesses.

How to Get a Cross-Reference Check on Your Part Number

Most XH sourcing enquiries stall on the same thing: the buyer is not sure what information the supplier needs, so the enquiry never gets sent. Here is the complete list.

Send us:

1. The original JST part number, if you have it — for example XHP-4, B4B-XH-A, S4B-XH-SM4-TB, or a terminal number (SXH-001T-P0.6, SXH-001T-P0.6N, SXH-002T-P0.6)
2. Circuit count and row configuration
3. Mounting type and entry direction — DIP or SMT, top entry (straight) or side entry (right-angle). If side entry, say whether you need the 9.2mm or the 7.6mm end-face-to-post dimension
4. Wire specification — AWG size and insulation outside diameter. At 2.5mm the insulation diameter is as much a design input as the conductor
5. Application and annual volume, so configuration, tooling and packaging can be matched to your programme
6. A drawing or a photograph, if the part number is unreadable or the design has been reverse-engineered. At 2.5mm a photograph next to a ruler will not separate XH from EH or XA — send the part number if you have it
7. Any qualification requirements — automotive, medical, or specific test standards

What you get back: a mapped KONNRA part number with the relevant product and engineering drawings, a specification comparison against your original part including the four windows in this guide, and a sample and quote plan.

Engineer’s Pre-Release Checklist

Run this before you release a drawing for a 2.5mm pitch connector.

• Pitch confirmed by measurement or part number — not by appearance. 2.5mm is not 2.54mm, and XH, EH and XA all sit at 2.5mm without sharing a footprint.
• Series confirmed — XH, EH or XA. At this pitch the part number is the only reliable identifier.
• Insulation outside diameter measured, not assumed, and checked against the 1.2–1.8mm KR2501 window. This is the window that fails quietly.
• Conductor size inside 22#–28#. If the harness uses AWG #30 or #29, the KR2501 as documented does not cover it.
• Temperature requirement checked. If the application exceeds +85°C or goes below −25°C, ask for the evidence behind KONNRA’s −40°C to +105°C rather than inheriting it from the data sheet.
• Current requirement checked against the reference conductor. KONNRA rates 3A at 24 AWG; if you need 3A on AWG #22, ask for the temperature-rise result at that conductor.
• Withstanding voltage taken from the specification, section 5.3 — 1,000V AC for one minute — and not from the 250V row on the product page.
• Mounting type decided — DIP or SMT — and the circuit count is inside the range that mounting type is documented for.
• Side-entry dimension confirmed — 9.2mm standard, or 7.6mm with the -1 suffix on the JST part.
• Boss requirement checked. JST’s with-boss top-entry header does not exist at 11, 13, 14, 15, 16 or 20 circuits.
• Circuit count checked at both ends — there is no 1-circuit and no 20-circuit KR2501.
• Plating stated explicitly if gold is required. PS-KR2501-01 §3.0 allows gold over nickel; the product page lists only tin over nickel.
• Housing resin pinned to one document. PS-KR2501-01 §3.0 says PA66; the housing page says PBT. Ask which applies to your part.
• Approach to the retention clause in section 6.4 agreed with the supplier, so the test you write matches the test that will be run.
• Crimp applicator data requested with the quote if you crimp in house.
• Mated height and cable bend radius checked against the enclosure.

➡️ Send us your drawing. We will review it against the KR2501 specification and come back with any mismatch we find — before you commit tooling. Submit a drawing for review

Frequently Asked Questions

What is a JST XH connector?

The JST XH is a 2.5mm pitch, single-row, wire-to-board crimp connector with a friction lock and a box-shaped shrouded header. It is rated 3A AC/DC with AWG #22 wire at 250V AC/DC, mates at a 9.8mm assembled board height, and accepts AWG #30 to #22 (0.05–0.33mm²) with insulation O.D. from φ0.9mm to φ1.9mm depending on terminal. JST developed it from its NH series and documents the header as interchangeable with the NR and NRD insulation-displacement connectors and the JQ board-to-board connector.

What is the KONNRA equivalent of the JST XH 2.5?

The KONNRA KR2501 series — a 2.5mm pitch XH wire-to-board connector covering 2–16 circuits at 3A and 250V, offered as DIP straight 180°, DIP right-angle 90°, SMT straight 180° and SMT right-angle 90° wafers, plus a housing and a crimp terminal. Housing H250101**0101G, terminal T25010PT0101F, and four wafer part numbers.

Which SXH terminal goes with which wire size?

JST splits the XH across three terminals, and the series range of AWG #30 to #22 is the union of them. SXH-001T-P0.6 is the standard normal-type contact, SXH-001T-P0.6N is the low-insertion-force type for easier mating with withdrawal, and SXH-002T-P0.6 covers the light end of the range. JST publishes the exact conductor and insulation window for each terminal in that terminal’s own drawing, and states that the low-insertion-force contact is less resistant to the vibration than the standard one — so it should not be specified by default. KONNRA documents a single terminal for the KR2501 with one insulation window of 1.2–1.8mm, so a JST terminal-plus-wire combination does not translate by copying the wire across.

Is the JST XH 2.5mm or 2.54mm?

2.5mm. The “2.54mm” label is common in the trade because 2.54mm is exactly 0.1 inch, but the two are not the same pitch. Across 16 positions the difference accumulates to 0.6mm — 37.5mm at a 2.5mm pitch against 38.1mm at 2.54mm.

What is the current and voltage rating of the JST XH?

3A AC/DC per contact with AWG #22 wire, at 250V AC/DC. KONNRA documents the KR2501 at the same 3A and 250V, but references the current rating to 24 AWG rather than AWG #22 — the same number measured on a different conductor. If your application runs near 3A, ask for the carried-current and temperature-rise result at the conductor you are actually using.

What wire gauge does the JST XH use?

AWG #30 to #22 (0.05mm² to 0.33mm²), with an insulation outside diameter from φ0.9mm to φ1.9mm, depending on which of the three terminals you select. The KR2501 is documented at 22#–28# with insulation 1.2–1.8mm, so it does not cover AWG #30 or #29 and does not cover insulation from 1.8mm to 1.9mm.

What is the insulation resistance and withstanding voltage of the JST XH?

Insulation resistance 1,000MΩ minimum. Withstanding voltage is 1,000 VAC applied for one minute with no breakdown or flashover. KONNRA’s specification states the same 1,000MΩ and the same 1,000V AC for one minute in PS-KR2501-01 §5.3, tested to EIA-364-20A. Note that KONNRA’s product page carries a 250V AC/minute row in its withstanding-voltage field — that is the rated voltage in the wrong row, and the specification is the controlling document.

What is the difference between JST XH and JST PH?

Pitch, current and voltage. XH is 2.5mm, 3A, 250V; PH is 2.0mm, 2A, 100V. They do not mate and do not share footprints. The KONNRA equivalents are KR2501 for XH and the KR2000-series for PH.

What is the difference between JST XH and JST EH?

Both are 2.5mm pitch families with the same 3A (AWG #22) and 250V AC/DC headline ratings, and they do not mate. The differences that decide it are the withstanding voltage — 1,000 VAC for the XH against 800 VAC for the EH — the assembled height, 9.8mm against 8.1mm, the wire range, #30–#22 against #32–#22, and the fact that the EH is through-hole only where the XH also offers SMT at 3, 4 and 6 circuits. The KONNRA equivalent for XH is KR2501; for EH it is KR2504.

Does the JST XH have an SMT version?

Yes, but only in 3, 4 and 6 circuits — S3B-XH-SM4-TB, S4B-XH-SM4-TB and S6B-XH-SM4-TB, side entry with a solder tab, supplied on embossed tape at 800 pieces per reel. Above six circuits JST catalogs the XH as a through-hole connector. KONNRA documents KR2501 SMT wafers as straight and right-angle across the 2P~16P range.

How many circuits does the JST XH come in?

JST’s housing table runs from XHP-1 through XHP-16, plus XHP-20, and headers are catalogued from 1 to 16 and 20 for top entry, and 2 to 16 for side entry. The KR2501 is documented from 2 to 16 — there is no 1-circuit and no 20-circuit equivalent, so check availability rather than assuming the range ends where the cross-reference does.

What is the mounting height of the JST XH?

9.8mm assembled board height, which JST describes as low profile for a 2.5mm pitch part. KONNRA documents the same 9.8mm figure, so enclosure clearance does not change when you cross-reference.

Can the JST XH header be used with IDC termination?

Yes — JST documents the XH header as interchangeable with the NR and NRD insulation-displacement connectors, and also with the JQ board-to-board connector, so the same PCB footprint can carry crimp, IDC or board-to-board termination. KONNRA does not document an NR, NRD or JQ equivalent for the KR2501, so confirm this specifically if your design depends on it.

Does the JST XH meet any industry standards?

JST lists CSA, TÜV and UL for the XH, and JST also states that the pin version conforms to JEMA’s Home Automation (HA) terminal standards. KONNRA’s KR2501 components carry UL file E482542. If a customer specification names CSA, TÜV or the JEMA HA standard as a requirement, say so at enquiry stage — it is a document request rather than a redesign, but it has to be asked for.

How do I identify which JST connector I actually have?

Measure the pitch — the centre-to-centre distance between adjacent contacts. 1.0mm is SH, 1.25mm is GH, 1.5mm is ZH, 2.0mm is PH, 2.5mm is XH. Then measure the housing across the contact field: for an XH it is (N − 1) × 2.5mm, so a 4-way housing measures 7.5mm and a 16-way measures 37.5mm. Because EH and XA also sit at 2.5mm, the housing profile and the part number are the deciding evidence — if you are still unsure, photograph the connector next to a ruler and send it to us.

How long does it take to get samples?

KONNRA can deliver complete connector set samples within 45 days. Connector production lead time is typically 2–3 weeks and wiring harness lead time typically 3–4 weeks.

Start Your Cross-Reference Check

KONNRA supplies the KR2501 series as individual components or as complete pre-crimped cable assemblies, in DIP and SMT configurations, with customisation available for application-specific requirements.

• Request a quote — KR2501 pricing, MOQ and configuration options for your circuit count and mounting type
• Request a sample — complete connector set samples within 45 days
• Request cross-reference verification — confirm KR2501-to-JST-XH equivalence against your specific part number, including the insulation and conductor windows
• Request drawings — series engineering drawing, product specification and package specification
• Request the crimp applicator data — if you crimp in house
• Request a vendor qualification pack — certificates, test capability summary and quality documentation
• Request adapter and transition cable assemblies — XH to PH, XH to 2.54mm DuPont, XH to JST VH, or other combinations
• Submit a drawing for review — we will flag any specification mismatch before you commit tooling

Contact KONNRA Electronics

• Phone: (86)-769-85449875
• Email: info@konnra.com
• Address: No.6 Nanchang South Road, Chijiao, Wangniudun, Dongguan, Guangdong, China
• Contact us

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Sources and method. Every figure in this guide is taken from a manufacturer document, and where two manufacturers — or two documents from the same manufacturer — disagree, the difference is stated rather than averaged. JST XH figures are taken from JST’s published XH series page and XH catalogue: pitch (2.5mm), circuit counts (1 to 16 and 20), current rating (3A AC/DC with AWG #22), voltage rating (250V AC/DC), temperature range (−25°C to +85°C, stated as including temperature rise under load), insulation resistance (1,000MΩ min.), withstanding voltage (1,000 VAC for one minute, no breakdown or flashover), conductor size (AWG #30 to #22, 0.05–0.33mm²), insulation O.D. (φ0.9–1.9mm), the friction lock, single-row configuration, top-entry and side-entry mating directions, through-hole and SMT mounting, the CSA / TÜV / UL standards listing, radial taping, the compatible IDC-style connector note (NR, NRD), the “original double-leaf contact design”, the “box-shaped shrouded header”, the with-boss header availability, the JEMA Home Automation (HA) terminal standard for the pin version, the nine housing colours and the header colour list, the housing and header part numbers with their A and B dimensions and quantities (XHP-1 through XHP-16 and XHP-20; the partially-filled XHP-2(10.0)-U and XHP-6(5.0)-U; top entry B…B-XH-A and the with-boss B…B-XH-AM including the absence of a boss version at 11, 13, 14, 15, 16 and 20 circuits; side entry S…B-XH-A with the 9.2mm and 7.6mm end-face variants; the glass-filled B…B-XH-2 series; and the SMT S3B-, S4B- and S6B-XH-SM4-TB at 800 pieces per reel), the three terminal part numbers, and the applicable PC board thickness. JST EH figures in the 2.5mm class comparison are taken from JST’s published EH series page. KONNRA KR2501 figures are taken from PS-KR2501-01 (Edition A1, dated 2022/2/26, 7 pages) sections 2.0, 3.0, 4.0, 5.1–5.3, 6.1–6.5, 7.1–7.11, 8.0, 9.0 and 10.0, and from the KR2501 product page and the six KR2501 component pages. Two limitations are stated openly. First, JST’s XH catalogue and its individual terminal drawings sit behind a registration wall on jst-mfg.com, so the terminal-specific conductor and insulation windows are not reproduced here as figures — JST publishes them per terminal, and they should be confirmed against the current drawing for the terminal you intend to use; this edition works from JST’s series-level window. Second, JST does not publish a series-level contact-resistance value, insertion and withdrawal force table, or environmental test programme for the XH, so the KR2501’s figures in those areas are checked against themselves — for example, all 45 entries of the section 8.0 force table reproduce from three arithmetic expressions — rather than reconciled against the original. The 48 ±4 hour salt-spray figure quoted for scale is from the product specification for the Molex Mini-SPOX 2.50mm system and is used only as an industry benchmark, not as a comparison with the XH. If a figure here disagrees with the current revision of a manufacturer document, the manufacturer document is right.