M Series Connectors
Are lightweight triplestart ratchet coupling type connectors designed for avionics, aerospace, Harsh Environment
Connectors, security, motorsport and heavy duty applications.
Shell size & selection
Two questions decide this before anything else. Will the connector live inside a sealed enclosure, or will it see weather? And what has to pass through it — how many signals, and how thick is the cable?
The B and K series answer the first question differently. The shell sizes answer the second. Everything on this page is arranged so you can settle both in a few minutes and leave with a part number.
Working indoors?B series — IP50, 00B to 3BView B series →
Working outdoors or wet?K series — IP68 mated, 0K to 3KView K series →
Already have the cable?Skip ahead — the size chart answers most of itJump to shell sizes ↓
9shell sizes, 00B through 3B and 0K through 3K
2–32contacts — multipole, coax, fibre, high voltage and mixed
>5,000mating cycles, tested to the same figure across both series
Two series, one decision
Both series share the same push-pull latch, the same insert layouts and the same contact options. What changes is the housing — and therefore where the connector is allowed to go.
| B series | K series | |
|---|---|---|
| Where it goes | Indoor equipment, protected enclosures | Outdoor, wet, washdown, temporary immersion |
| Sealing | IP50 dust protected, not water resistant | IP68 mated / IP66 unmated |
| Shell range | 00B, 0B, 1B, 2B, 3B | 0K, 1K, 2K, 3K |
| Keying | 13 options — key G standard, plus A–M and R | 9 options — key G standard, plus A–F, L and R |
| Temperature | −55 to +250 °C | −55 to +250 °C |
Read the sealing row twice. B series is IP50: it keeps dust out and does nothing about water. That is not a weakness — inside a cabinet it is the correct and cheaper choice. K series reaches IP68 only when mated, and sits at IP66 when the halves are apart. In storage, or on a panel before the plug goes on, it is not submersible.
The next section is where most projects go wrong: the number in front of B and the number in front of K are not the same size.
The numbers do not line up
A 1B and a 1K look like the same part in two finishes. They are not. The K series carries an additional sealing stack, so every K number sits roughly one and a half shell sizes above its B counterpart.
!
14.1 mm, not 12.1. An 0K needs a 14.1 mm panel hole. A 1B needs 12.1 mm. Design a panel around the B series, then move to the sealed version, and the hole is undersized.
If you are comparing the two ranges on the fly, remember the offsets: 0K falls between 1B and 2B, 1K between 2B and 3B, 2K between 3B and 4B.
Three questions to a part number
Working out the right shell takes three inputs, in this order. Skipping the first one is the usual reason a cable will not fit.
1
Thickest conductor?
Sets the minimum contact size.
2
How many signals?
Sets the insert configuration.
3
Cable outer diameter?
Sets the collet code.
Here is the whole thing on one real cable. Six signal cores at 0.5 mm², jacket measuring 6.0 mm. Six cores point to a six-contact insert. A 6.0 mm jacket takes a D62 collet. Both land inside the 1B shell — 12.1 mm panel hole, M12×1.0 thread, D-type collet. Specify it as EGG.1B.306.CLL for a fixed socket with female solder contacts.
Size chart
Panel cut-out and thread are the two numbers your mechanical drawing has to carry. Contact counts and collet codes are starting points for each shell.
| Shell | Cut-out Ø | Panel thread | Contacts | Collet code | |
|---|---|---|---|---|---|
| 00B | 7.1 mm | M7×0.5 | 2–4 | D27 / D32 | View |
| 0B | 9.1 mm | M9×0.6 | 2–9 | D32 / D42 | View |
| 1B | 12.1 mm | M12×1.0 | 2–14 | D42 / D52 / D62 | View |
| 2B | 15.1 mm | M15×1.0 | 2–19 | D62 / D72 / D82 | View |
| 3B | 18.1 mm | M18×1.0 | 2–32 | D82 / D92 / D99 | View |
| 0K | 14.1 mm | M14×1.0 | 2–9 | C or K type | View |
| 1K | 16.1 mm | M16×1.0 | 2–14 | C or K type | View |
| 2K | 20.1 mm | M20×1.0 | 2–19 | C or K type | View |
| 3K | 24.1 mm | M24×1.0 | 2–32 | C or K type | View |
Collet codes read as cable diameter: D42 takes a 4.2 mm jacket, D62 takes 6.2 mm. Pick the code that matches the jacket, not the one that matches the shell number.
If your panel hole is already cut, work backwards from the two left-hand columns. If it is not cut yet, choose the shell from the cable and stay inside the series that suits the environment.
What both series do well
Six things hold true across every shell size and both series. They are also the reason these connectors end up on camera rigs and operating tables rather than in a junction box.
Push-pull latch
Push to lock, pull the outer sleeve to release. No twisting. Rated 10–2000 Hz at 15 g.
360° screening
Full-perimeter shield, >80 dB at 1 GHz, >95 dB at 10 MHz.
Keying options
13 keyways on B, 9 on K — similar plugs cannot cross-mate.
Mating life
>5,000 cycles. Ten insertions a day for well over a year.
Housing and insulator
Brass shell, PPS insulator; PSU, PPSU and PEEK for sterilisation.
Mixed loading
Coax, fibre, high voltage, fluidic and multipole in one shell.
Six places these connectors are already working
Each card gives the setup, the part that usually fails, and how the connector is actually mounted and wired.
High-speed camera on an outdoor shoot
Setup
Camera on a moving rig, rain and vibration.
Fails
A plug that backs out mid-take.
We fit
K series 1K or 2K
How
The socket mounts through the camera housing on the M16×1.0 lock nut and its O-ring. The cable side is assembled with a C-type collet, so strain lands on the jacket grip rather than the solder cups. A socket cap goes on whenever the camera is packed away.
Operating-room patient monitor
Setup
Six to eight signal lines in one bundle, handled by different staff every shift.
Fails
A cable plugged into the wrong port.
We fit
B series 1B or 2B, split keying
How
Identical shells are ordered with different key letters — A through M, plus R — so two visually identical cables physically cannot mate with the wrong socket. Colour-coded insulating washers under the panel nut label each port from across the room.
Outside-broadcast truck
Setup
Video, power and control running down one cable run, rigged and struck daily.
Fails
The connector wearing out, or needing three separate runs.
We fit
B series 2B, mixed insert
How
One 2B shell carries coax and multipole contacts together, so the run is wired once at the bench. A PU bend relief on the collet nut keeps the jacket from kinking every time the cable is coiled.
Outdoor environmental sensor
Setup
Enclosure on a pole, five years of sun, rain and salt air.
Fails
Water finding its way in at the connector, not the housing.
We fit
K series 0K or 1K
How
The socket pulls up against the enclosure wall on an M14×1.0 or M16×1.0 nut, sealing on its O-ring. The plug carries its own gasket stack, so IP68 is only reached once it is mated. Keep a cap on the socket during service.
Production line control cabinet
Setup
Tight panel space, thirty signals, no water anywhere near it.
Fails
The wiring loom between the panel and the board.
We fit
B series 3B, high-density insert
How
Use the PCB version — the socket solders straight to the board and mounts through the cabinet wall, which removes the internal loom and one whole set of terminals.
Test and measurement instrument
Setup
Mated and unmated dozens of times a day on the bench.
Fails
The contacts, long before anything else.
We fit
B series 0B or 1B, crimp contacts
How
Crimp rather than solder, so a damaged cable is rebuilt at the bench in minutes without opening the instrument. At 5,000-plus cycles the connector outlives most of the test rigs it is fitted to.
Reading a part number
Once you can read one, the catalogue stops being a wall of text. Take the code below apart from left to right.
EGGHousing style: fixed socket, nut fixing
1BShell size 1, B series
306Multipole insert, 6 contacts
CLLFemale contacts, solder termination
The 3 in 306 marks the multipole insert family; the last two digits are the contact count, so 310 is a ten-way and 332 is a 32-way. The final group tells you the sex and the termination: CLL is female solder, CLA is male solder. Change one letter and you have a different connector, which is why we confirm the full string before quoting.
Sockets — EGG fixed socket with nut / EEG PCB mount / ECG right-angle / EBG solder panel / PHG with cable collet
Plugs — FGG straight / FHG right-angle / FAG panel mount / FNG cable mount
Three mistakes we see most
×
Mating a 1B plug to a 1K socket
✓
Same number, different shell. K runs about 1.5 sizes larger.
×
Choosing by contact count, ignoring the jacket
✓
The jacket sets the collet, and the collet decides whether it assembles at all.
×
Assuming a K series is sealed on the shelf
✓
IP68 only when mated. Apart, it is IP66.
Ordering in three steps
Send itCable outer diameter, contact count, indoor or outdoor.
We answerWithin 24 hours, a shell and a full part number.
You getConfirmation and a quote.
If your cable is already made, send us the jacket diameter and contact count and we will do the lookup for you.
Frequently asked
What is the difference between B series and K series?
B series is the indoor range, sealed to IP50 — dust only. K series is the outdoor range, IP68 when mated and IP66 when apart. Both use the same push-pull latch and the same insert layouts; the shells differ in size.
Is the B series waterproof?
No. IP50 keeps dust out and does nothing about water. If the connector will see rain, washdown or temporary immersion, use the K series.
Can a 1B plug fit a 1K socket?
No. The K series adds a sealing stack, so every K shell sits about one and a half sizes above the same B number. An 0K needs a 14.1 mm panel hole; a 1B needs 12.1 mm.
How do I choose the right shell size?
Three inputs, in order. The thickest conductor sets the contact size, the number of signals sets the insert, and the cable jacket sets the collet. The shell is whichever one holds all three.
Not sure which shell you need?
Send your cable diameter and contact count, and we will come back with a shell, a part number and a price — usually within one working day.
Browse the push-pull range →