|
M8 vs M12 Circular Connectors: Size, Pin Count & Current Rating Comparison Select Connector Comparison Guide
M8 vs M12 Connectors: Size, Pin Count & Current Rating ComparedM8 vs M12 connectors come down to thread size, pin count, and current rating. This page shows exactly which format and cordset fits your sensors, actuators, and fieldbus networks. Quick answer M8 connectors use an 8mm thread and typically carry about 3A in 3-4 pin form for compact sensors; M12 uses a 12mm thread, carries around 4A, and supports 3-12 pins for I/O, power, sensors, actuators, and DeviceNet/CANopen networks. M8 and M12 are not interchangeable, so pick the format that matches your device's port thread.
The Bottom LineChoose by port thread first. If your device has an 8mm barrel, M8 cordsets such as the Hirschmann ELKA-K 4408 M8 4-pin (3A, 30V, IP67) are the fit for tight conveyor and robotics sensor spots. For M12, pick the Hirschmann EF124 4-pin when you need a 5m reach for standard I/O, or the Lumberg RKT 4-3-659 3-pin when you're running basic 3-wire DC sensors; especially in cold, since it's rated to -40C and crosses Turck RK 4T-2. For DeviceNet or CANopen network nodes in washdown areas, the Lumberg 0935 253 104/5 M 5-pin male shielded cordset with IP69K is the correct choice. Confirm male/female gender and pin count against your device pinout, and stay within the printed voltage/current ratings before ordering. How M8 and M12 circular connectors workBoth are threaded, round connectors defined by their coupling thread diameter: 8mm for M8, 12mm for M12. The thread size and keying prevent cross-mating, so an M8 cordset will never thread onto an M12 port. Pin count sets the function:
Current rating is driven by contact size and conductor gauge. M8 typically tops out near 3A (as on the ELKA-K 4408 at 24 AWG conductors), while M12 handles about 4A on 18 or 22 AWG conductors. Never exceed the printed rating. These are the listed limits, not headroom. Sealing is by O-ring and overmolded jacket; IP67 covers dust-tight plus temporary immersion, IP68 adds prolonged immersion, and IP69K adds high-pressure, high-temperature washdown. Molded cordsets (where the connector is factory-overmolded to the cable) eliminate field wiring errors and are the reliable default over field-wireable versions. Higher pin counts explained12-pin connectors appear on encoders, servo feedback, and multi-channel I/O blocks that carry many signals through one shell. As pin count rises, per-contact current drops because the contacts shrink. That's the core tradeoff: more signals or higher current, rarely both in one shell. For the products here:
How to choose an M12 cordsetWork through these in order:
Check cross-references too. Many M12 cordsets cross with other manufacturers. For example, the Lumberg RKT 4-3-659 crosses with Turck RK 4T-2, which simplifies replacement on existing machines. Select M8 vs M12 cordset comparison
Common Mistakes (and the Fix)✗ Assuming M8 and M12 are interchangeable ✓ Check the device port thread. 8mm needs M8, 12mm needs M12; they can't mate. ✗ Ordering the wrong gender ✓ A male device port takes a female cordset. Verify before you buy. For example, the 0935 253 104/5 M is male, EF124 & RKT are female. ✗ Using a 4-pin cordset on a 5-pin DeviceNet port ✓ Use a 5-pin cordset like the 0935 253 104/5 M so the shield/drain conductor is supported. ✗ Ignoring IP rating for washdown lines ✓ Specify IP69K (like on the 0935 253 104/5 M) for high-pressure cleaning, not just IP67. ✗ Picking PVC jacket for oily or cold areas ✓ Choose PUR jacket cordsets; the RKT is rated to -40C for cold environments. ✗ Using a non-ATEX cordset in a hazardous area ✓ None of these are ATEX-listed; specify an ATEX-marked connector for classified zones. Frequently Asked QuestionsWhat is the difference between M8 and M12 connectors?M8 has an 8mm threaded coupling, M12 a 12mm one; they physically cannot mate. M8 typically handles about 3A and suits compact sensors; M12 usually carries about 4A and supports more pins (3-12), so it covers I/O, power, and DeviceNet/CANopen networks. Choose the format that matches your device's port thread. What is an M12 cordset and how do I choose one?An M12 cordset is a cable factory-overmolded to an M12 connector, eliminating field wiring errors. To choose: confirm gender (a male port takes a female cordset), match the pin count to your device (3-pin for basic DC sensors, 4-pin for standard I/O, 5-pin for DeviceNet/CANopen), pick a cable length accounting for slack, and check the IP rating against your environment: IP67 general, IP68 immersion, IP69K washdown. Is there an M12 male connector for DeviceNet?Yes, there are a number of them. One example is the Lumberg 0935 253 104/5 M, which is a 5-pin M12 male straight cordset built for DeviceNet and CANopen, with a shielded PUR jacket and IP69K rating for washdown lines. Verify your device port is female before ordering, since this cordset is male. Can I use an M12 connector in an ATEX or washdown area?For washdown, choose an IP69K-rated cordset like the Lumberg 0935 253 104/5 M. ATEX-certified M12 connectors exist but you must verify the specific ATEX marking and gas/dust group on the part before installing in a hazardous (Ex) area. None of the four cordsets in this comparison guide are ATEX-listed, so do not use them in a classified hazardous location. What pin count do I need — 3, 4, or 5 pin?3-pin M12 suits 3-wire DC sensors (V+, V-, signal). 4-pin covers standard sensors and actuators with two signals or IO-Link. 5-pin is used for DeviceNet/CANopen networks (it carries the shield/drain) or dual-signal devices. Always match the cordset pin count to the device pinout — a 4-pin cordset on a 5-pin port loses the drain conductor. Terms Worth Knowing
|