| Full title | Connectors for electrical and electronic equipment. Product requirements. Part 2-101: Circular connectors. Detail specification for M12 connectors with screw-locking |
| Publisher | IEC (TC 48/SC 48B, Electrical connectors); adopted in Europe as EN IEC 61076-2-101 |
| Current edition | IEC 61076-2-101:2024, edition 4.0, published 27 November 2024. Replaces the 2012 third edition |
| European version | EN IEC 61076-2-101:2025, which supersedes EN 61076-2-101:2012 |
| Related standards | IEC 61076-2-109 (X and H coding), IEC 61076-2-111 (power M12), IEC 61076-2-113 (hybrid power and data), IEC 60529 |
What it covers
IEC 61076-2-101 is the detail specification for circular connectors with an M12 screw-locking thread. It covers connectors with 2 to 17 ways, for data transmission at frequencies up to 100 MHz and for signal and power at up to 250 V and 4 A per contact.
It covers fixed and free connectors, each either rewirable or non-rewirable. Male contacts are round, with diameters of 0.6 mm, 0.76 mm, 0.8 mm or 1.0 mm depending on the number of ways and the coding. All contacts in one connector are the same size.
The codings are mechanical keys. They stop differently coded male and female connectors from mating. “M12” refers to the thread size of the locking nut.
Codings in this part
The 2024 edition defines four codings. The interface drawings are in Clause 5.4.
| Coding | Ways in the 2024 edition | Notes |
|---|---|---|
| A | Up to 5, 8, 12 and 17 ways | The 17-way style was added in the 2012 edition |
| B | 5 ways | |
| C | 3, 4, 5 and 6 ways | 3-way and 4-way styles include a PE contact; 5-way and 6-way include an FE contact |
| D | 4 ways | Used as data connectors, up to 100 MHz and 60 V DC |
The 2012 edition also included a P-coding. The 2024 edition removed it.
M12 codings in other parts
Several common M12 codings are not in Part 2-101. They have their own detail specifications in the IEC 61076-2 series.
| Part | Scope | Codings |
|---|---|---|
| IEC 61076-2-109 | M12 x 1 screw-locking connectors for data up to 500 MHz, 0.6 mm contacts, IP65/IP67. First edition 2014 | X and H (different contact layouts, not interchangeable) |
| IEC 61076-2-111 | Power connectors with M12 screw-locking, 4 to 6 ways. Edition 2.0 published 11 December 2025. The 2017 first edition specified 1.0 mm and 1.5 mm contacts | E, F, K, L, M, S and T in the 2017 first edition |
| IEC 61076-2-113 | M12 screw-locking connectors with two data pairs and power contacts up to 12 A, data up to 100 MHz. First edition 2017 | Defined in the part (letters not listed here) |
The 2025 edition of Part 2-111 rates contacts at 8 A, 12 A or 16 A, at 50 V AC / 60 V or 630 V depending on the coding.
So a connector described as M12 X-coded is specified by IEC 61076-2-109, not Part 2-101. An L-coded or K-coded power connector is specified by IEC 61076-2-111.
Changes in the 2024 edition
- Dimensional information (Clause 5) and characteristics (Clause 6) updated, with new subclauses.
- New free connector style NF added.
- Fixed connectors with glass-to-metal seals (former styles WM, XM, YM, ZM, WF, XF, TF and ZF) removed.
- P-coding removed.
- Steel conduit thread annex deleted. New informative Annex B on cable outlet orientation in relation to coding.
- Dimensions for former styles AM and BM moved to a new normative Annex C.
The 2012 edition had already added the 17-way A-coded style, removed type designation and ordering information, and absorbed the content of IEC PAS 61076-2-108.
What it means in practice
- Match the coding and number of ways on both halves. Codings are designed not to cross-mate.
- Check which part a datasheet quotes. Part 2-101 covers A, B, C and D. X-coding is Part 2-109. Power codings are Part 2-111.
- Ratings depend on coding and way count. The 250 V and 4 A figures are the maximums across the part, not the rating of every style.
- The IP code of a mated pair is tested to IEC 60529. Check whether the stated rating applies mated, unmated or capped.
- Glass-to-metal sealed fixed connectors are no longer in the 2024 edition.
Related reading: M12 X-code vs D-code: what’s the difference? · Industrial connectivity: M12 connectors, assemblies and cable.