LEMO B-Series Cross-Reference Guide

LEMO B-Series Push-Pull Connector Cross-Reference and Equivalents: A 10-Axis Walk-Through for Buyers in Russia and the CIS

icsourcedirect.com is an independent connector and interconnect distributor based in Shenzhen, China. The LEMO B-series push-pull family (sizes 0B, 1B, 2B, 3B) is one of the lines we catalogue in active form — EGG.1B.307.CLL, EGG.2B.312.CLL, EPG.0B.305.HLN, GMA.0B.035.DA, ECG.1B.308.CLV and FGG.2B.319.CYCD62Z are all listed at /manufacturers/lemo. A B-series cross-reference is a candidate, not a guarantee: it must be evaluated on ten axes (outline, dimensions, pin layout, electrical, mechanical, environmental, IP, temperature, materials and plating, certifications) before any production decision. As Russian buyers phrase it: «Аналог разъёма LEMO B-серии по числу пинов и шагу».

By the icsourcedirect.com Shenzhen sourcing desk. Last updated September 2026. Data notes: the LEMO part numbers and the per-axis evaluation cited in this article come from our internal catalogue specifications for the B-series lines currently listed and from the manufacturer datasheets published by LEMO; any axis value marked as unknown could not be verified from either source and is stated as such.

What the LEMO B-Series Is, and Where It Is Used

The B-series designation is one of several push-pull families LEMO publishes (B, K, S, T, 00, 0M, 1M, 2M). The B-series sits in the middle of the line: physically smaller than the 2M and 3M series, larger than the 0M series, and built around a quarter-turn self-locking latch with a visible alignment key on the housing. Common B-series pin counts in our catalogue are 2 to 14 contacts in straight plug (FGG), fixed socket (EGG), and receptacle (GMA / EPG) forms. Typical applications include patient monitors and ECG leads, ultrasound imaging probes and handpieces, test and measurement fixtures, broadcast and pro-audio panels, and high-end industrial sensors — environments where the latching action keeps the connection stable under vibration that would back off a bayonet or threaded mount, and where keyed mating prevents mis-rotation during clinical or measurement use.

These applications are not interchangeable. A connector that survives 5,000 matings on a test bench can be a poor choice on a patient monitor that is wiped with disinfectant dozens of times per week. A connector that is sealed to IP68 in a lab cable can fail in a washdown line if the cable collet was not the sealed variant. The B-series addresses these variants by offering different back-end terminations, different plating thicknesses, and different sealing options under the same housing outline. A cross-reference that ignores those variants is not a cross-reference — it is a guess.

The Buyer Question: When Can a LEMO B-Series Be Substituted?

In practice, three scenarios land at our desk most often:

Discontinued or allocation-blocked B-series line — a particular part number is end-of-life at the manufacturer, or the franchise channel is on allocation, and the buyer needs a same-fit replacement before the next production batch runs.
Used-equipment retrofit — a buyer has imported a European or US-built instrument with LEMO connectors on the back panel and needs to source spares after the original warranty period has expired.
Cost engineering on a non-medical design — a buyer originally specified LEMO B-series for the brand, then re-evaluated the BOM and asked whether a same-footprint, same-pin-count circular from a different brand can substitute the original.

All three are legitimate procurement problems. None of them is solved by visual matching. The substitution has to be evaluated axis by axis. The 10 axes are listed below in the order they should be checked — the first three are blockers; if any of them differs, the substitution stops there.

The 10 Axes, Applied to the LEMO B-Series

The axis definitions and source of evidence are given in our connector substitution framework on the Compare page. The values below come from our catalogue specifications and from the LEMO datasheets that the original manufacturer publishes; where a value could not be verified from those two sources, it is listed as unknown.

1. Form / fit outline — matched · differs · unknown

Matched when: the substitute uses the same outer diameter (about 9 mm for 0B, 12 mm for 1B, 15 mm for 2B), the same panel cut-out, the same latching sleeve travel, and the same keying geometry.
Differs when: the substitute is a threaded-mount or bayonet-locking circular with the same pin count but a different coupling nut. The plug will not mate.
Unknown when: the substitute datasheet only gives electrical specs and not a mechanical drawing. Treat the axis as unknown and stop.

2. Dimensions — matched · differs · unknown

Matched when: pin count is identical and pitch is identical. B-series has family-specific pitch per pin count; deviating from the LEMO pitch is a direct footprint mismatch.
Differs when: a substitute offers the same number of pins but on a different pitch, or a different row layout (for example, a substitute uses a 2-row pin pattern where the B-series uses a single row).
Unknown when: the substitute datasheet does not publish a mechanical drawing with pitch dimensions.

3. Pin-to-pin layout — matched · differs · unknown

Matched when: the substitute lists each contact number against the LEMO datasheet reference and the numbering is identical. The PCB footprint is the same.
Differs when: a substitute reverses the numbering (pin 1 becomes pin N) or swaps the male and female sides — the B-series is gendered: FGG plugs have male contacts (or female, depending on contact type), EGG sockets have the opposite gender; a same-shape substitute with the gender reversed will short the wrong pairs.
Unknown when: the substitute datasheet only gives a photograph or a generic pin map without numbers.

Blocker rule: if any of axes 1, 2 or 3 fails or is unknown, the substitution is declared non-viable before any of axes 4 through 10 are checked. Saving the rest of the evaluation for later is a known procurement mistake.

4. Electrical rating — matched · differs · unknown

Matched when: the substitute's rated current per contact, rated voltage, and contact resistance are at or above the original LEMO B-series values (commonly 3 A to 10 A per contact depending on pin count, and 250 V to 1000 V depending on family).
Differs when: the substitute is rated below the original, even by a small margin, on a line that runs near the original rating. A 2 A substitute on a 5 A signal line is a derating the application may not tolerate.
Unknown when: the substitute datasheet does not publish an electrical table.

5. Mechanical behaviour — matched · differs · unknown

Matched when: the substitute's mating cycle rating is at least 5,000 cycles (the typical B-series baseline), the insertion force is in the same range, and the contact retention matches the original.
Differs when: the substitute is rated for fewer cycles than the application needs. A 500-cycle substitute on a test fixture that re-mates hourly will fail.
Unknown when: the substitute datasheet does not state a cycle rating.

6. Environmental class — matched · differs · unknown

Matched when: the substitute is rated to the same application class (industrial, medical non-implantable, test and measurement) and the same vibration / shock rating.
Differs when: the substitute is a consumer-grade part with no industrial vibration rating, or vice versa — crossing class is the most common substitution mistake on the B-series.

7. Ingress protection — matched · differs · unknown

Matched when: the substitute datasheet states an IP rating (for example IP50, IP66, IP68) under the same conditions (mated or unmated) and the rating equals the original.
Differs when: the substitute has no IP statement at all — IP cannot be inferred from the visible presence of an O-ring, because the seal geometry, compression set, and material compatibility with common disinfectants differ.
Unknown when: the substitute datasheet gives an IP rating only in marketing copy and not in the test conditions.

8. Temperature range — matched · differs · unknown

Matched when: the substitute's operating temperature window covers the original's window, including any autoclave or low-temperature reflow stage in the assembly process.
Differs when: the substitute is rated to a narrower window — for example, a -25 °C to +70 °C part on a design that has a -40 °C to +85 °C requirement.
Unknown when: the substitute datasheet gives no temperature statement.

9. Materials and plating — matched · differs · unknown

Matched when: the substitute uses the same contact base material (typically brass or bronze with beryllium-copper options on the B-series) and the same or thicker gold plating thickness (typically given in μin). Tin-plated substitutes are a frequent mismatch on the B-series, and a tin contact on a low-voltage signal line will fail open before the gold version does.
Differs when: the substitute substitutes tin for gold, or uses a thinner gold layer (for example 10 μin against a 30 μin original).
Unknown when: the substitute datasheet does not publish contact material or plating thickness.

10. Certifications — matched · differs · unknown

Matched when: the substitute holds the same UL / CSA file, the same IEC standard, and where applicable the same medical-grade supply chain documentation.
Differs when: the substitute has no certifications at all, or holds certifications that are not accepted for the application (for example, a non-medical supply chain on a medical assembly).
Unknown when: the substitute datasheet claims a certification without a file number — this is treated as no certification, not as the named certification.

Where to Stop the Substitution — Fail-Safe Scenarios

Three situations should stop a LEMO B-series cross-reference immediately, and these are the cases where substitution is not recommended without manufacturer confirmation:

Patient-contact medical assembly where the connector mates with a cable that runs to a patient lead. A substitute with a different plating thickness or a different sterilization chemistry tolerance is a clinical risk. The buyer should return to the original manufacturer or to a documented cross-reference that the manufacturer has confirmed in writing.
Sealed washdown line where the substitute has no IP statement at all. The presence of a visible O-ring on a substitute is not an IP rating. Avoid substituting in this case — the substitute is declined on axis 7 alone.
High-cycle test fixture where the substitute is rated below 5,000 mating cycles and the fixture re-mates more than once per shift. Do not substitute in this case — the substitute is declined on axis 5.

A fourth, softer scenario: when the substitute is technically acceptable on axes 1 through 10 but the buyer's qualification record already lists the LEMO B-series as the approved part, the substitution should still require a written engineering change rather than be silently absorbed by procurement. Approval belongs to engineering, not to sourcing.

How an Independent Sourcing Desk Handles This in Practice

icsourcedirect.com is an independent distributor and procurement agent based in Shenzhen, not an authorized LEMO distributor, and we do not hold manufacturer-issued franchised-channel certifications. What we can do for buyers in Russia and the CIS is document a B-series substitution candidate on each of the ten axes, mark every value that cannot be verified as unknown, and leave the engineering sign-off to the buyer. A few practical notes from the desk:

We do not use any phrase that implies a guaranteed, one-to-one match on our articles or quotations. Every cross-reference is a candidate.
Every B-series candidate we quote is sourced through the Shenzhen channel — original-manufacturer lines, authorised resellers, and allocation-channel lines where the channel can be documented. Lines whose channel cannot be documented are declined rather than shipped, in line with our authenticity-screening process on the Quality page.
Per-line quotation includes the manufacturer part number, the proposed substitute or cross, the price, the MOQ, the lead time, and the available packaging form (full reel, cut tape, tube, bag, tray), as described on the Procurement page. No blanket MOQ is applied across the catalogue. Send the BOM or the single part to the inquiry form for a per-line quote.
For shipments into Russia and the CIS, we offer door-to-door delivery on a weekly consolidated air lane cleared under DDP, with customs and duty included where the quotation states DDP. We screen end users and end uses, classify before quoting, and decline transactions that cannot be screened. The exact transit time and the exact destination routing are confirmed on each quotation rather than stated as a general commitment.
Documents provided as standard on a Russia / CIS shipment are a commercial invoice, packing list and certificate of origin. Manufacturer-issued certificates of conformance or test reports depend on the specific manufacturer, part and channel and are confirmed per line before sourcing.

Verify against the original manufacturer datasheet and your own qualification process before adopting any cross-reference as the production part.

When This Article Is Not Enough

This article covers the LEMO B-series push-pull family. It does not cover the LEMO S, K, T, 0M, 1M or 2M families, which use different latching geometries and different pitch patterns; a cross-reference between B and K, or between B and S, fails on axis 1 (form / fit outline) by definition. It also does not cover used-equipment tear-down samples where the connector has no markings at all — for that case, see our unknown-connector identification walk-through. For cross-references on heavy-duty rectangular housings (HARTING Han family) or on harsh-environment automotive circulars (Amphenol AT), see the corresponding walk-throughs for those families.

Next Step

Send the LEMO B-series part number (or a list of part numbers) to the inquiry form on this site. Where a part number is not available, attach a photograph of the connector against a ruler so the diameter and pin count are visible, and a photograph of any marking on the housing. We will return a line-by-line cross-reference evaluation with each of the ten axes marked matched, differs, or unknown, and a separate quotation with MOQ, lead time and packaging form per line. All lines consolidate into a single shipment on the next available consolidation. Typical first response on a single-part RFQ is one business day during local business hours.

FAQ

Is a same-shape connector a guaranteed replacement for a LEMO B-series?

No. Same outline and same pin count are two parameters among ten. Plating thickness, contact gender, IP rating, temperature window and certification status can all differ between a B-series and a substitute that looks identical at a glance. The ten comparison axes are checked per line and any axis that cannot be verified from the manufacturer datasheet is marked as unknown. The engineering sign-off belongs to the buyer, not to the sourcing desk.

Which LEMO B-series applications should never be cross-referenced without manufacturer confirmation?

Patient-contact medical assemblies (cables that mate to patient leads), sealed washdown lines where the substitute has no IP statement, and high-cycle test fixtures where the substitute is rated below the application's mating-cycle count. In those three cases the substitution is declined before the rest of the evaluation, regardless of how many other axes match.

Can a LEMO B-series connector be sourced from China for delivery to Russia or the CIS?

Yes. The B-series lines that we currently list (EGG.1B.307.CLL, EGG.2B.312.CLL, EPG.0B.305.HLN, GMA.0B.035.DA, ECG.1B.308.CLV, FGG.2B.319.CYCD62Z and others) can be quoted per line and consolidated into one shipment. Pricing, MOQ and lead time are confirmed on each quotation rather than stated as a catalogue-wide number. Documents supplied as standard are a commercial invoice, packing list and certificate of origin.

What documents accompany a DDP shipment of connectors to Russia?

A commercial invoice, a packing list and a certificate of origin are issued as standard on every shipment. Under DDP, customs clearance and duty are handled by the desk so the goods arrive at the buyer's door with nothing further to pay. Manufacturer-issued certificates of conformance or test reports depend on the specific manufacturer, part and channel, and are confirmed per line before sourcing rather than included as a default line item.

What is the difference between a LEMO B-series and a LEMO K-series or S-series?

The B-series, K-series and S-series are three different LEMO families with different housing diameters, different latching sleeve geometries and different pitch patterns. A connector from one family will not mate with a connector from another family, even when the pin count is the same. A cross-reference between families fails on form and fit outline (axis 1) before any electrical axis is checked.

How long does delivery from Shenzhen to Moscow or a regional hub in Russia take?

On the dedicated Russia / CIS lane, transit is typically seven to fifteen days door-to-door with customs included under DDP. Exact timing is confirmed per shipment because it depends on the consolidation schedule and the destination city. Outside the Russia / CIS lane, standard express delivery from Shenzhen is typically three to seven business days.

Is a higher temperature rating enough to substitute a LEMO B-series?

No. A wider temperature window is one axis among ten. The other nine axes — outline, dimensions, pin layout, electrical, mechanical, environmental, IP, materials and plating, and certifications — still have to match. A part with a wider temperature rating but a thinner plating or a different IP rating is not a valid substitute for the B-series.