M8 vs M12 Connector: A Guide to Circular Industrial Connectors
Time:2026-11-09
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Walk any factory floor and you’ll see small round connectors on sensors, actuators, vision cameras and Ethernet switches. Almost all of them are M8 or M12 — named for the thread diameter in millimetres — and choosing between them comes down to how many wires you’re carrying and how rugged the environment is.
M8: the compact sensor standard
M8 is the 8 mm thread you’ll find on proximity sensors, photoeyes and compact automation. It carries 2 to 8 pins depending on the version, and it’s the right call when space is tight and the signals are low-level.
M12: the workhorse of industrial Ethernet
M12 is the 12 mm thread with real versatility — 2 to 8 pins and, critically, X-coded versions built for gigabit industrial Ethernet. When a line runs PROFINET or EtherNet/IP over M12, that’s X-coding doing the work.
Coding: the letter that prevents disaster
The letter after M12 isn’t decoration — it’s a key that stops you from plugging a power cable into a signal port:
A-coded — sensors, DC power, signals; B-coded — fieldbus (PROFIBUS); C-coded — AC power; D-coded — 100 Mbit Ethernet; X-coded — gigabit Ethernet.
IP rating: match it to the washdown
Our M8 and M12 connectors come in IP67 (dust-tight, temporary immersion) and IP68 (continuous immersion) versions. Outdoor LED lighting and food-line washdowns want IP68; a dry control cabinet can settle for less. Don’t over-spec, but never under-spec the seal.
At a glance
| Series | Thread | Pins | Typical use |
|---|---|---|---|
| M8 | 8 mm | 2–8 | Sensors, photoeyes, compact automation |
| M12 A-coded | 12 mm | 2–8 | Signals, DC power |
| M12 D-coded | 12 mm | 4 | 100 Mbit Ethernet |
| M12 X-coded | 12 mm | 8 | Gigabit Ethernet |
We manufacture M8 and M12 connectors — straight and right-angle, field-attachable and panel-mount, IP67 and IP68 — in our Shenzhen plant. Unlike sourcing a branded industrial line, a factory-direct order lets you match the exact coding, pin count and cable length without a distributor’s markup or a minimum that assumes you’re a machine builder buying ten thousand at once.
Need a hybrid that carries power and signal in one shell, or a custom overmoulded cable? We do those too.
Frequently Asked Questions
What is the difference between M8 and M12?
Thread diameter — 8 mm vs 12 mm. M12 also supports more pins and gigabit Ethernet via X-coding, so it suits higher-speed and higher-pin-count industrial links.
What does M12 X-coded mean?
X-coding is a keyed M12 layout for gigabit industrial Ethernet, preventing it from being plugged into a power or signal port.
Do you offer IP68 versions?
Yes, for outdoor and washdown applications. We also offer IP67 versions where continuous immersion isn’t required.
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