Different Size Pin Diameters in M8 and M12 Circular Connectors

Various pin sizes are allowed for the M8 and M12 circular connectors. Occasionally, we will encounter different sized pins in industrial sensors such as the ones shown in Figures 1 and 2.

  • According to IEC 61076-2-104, the M8 connectors may have male pins with diameters of 0.6, 0.7, and 1 mm.

  • According to IEC 61076-2-111:2017, the M12 connectors may have male pins with diameters of 1.0 and 1.5 mm.

Figure 1: Image of M8 connectors with different sized pin connections.

Connector compatibility

As a general statement, the connectors are compatible. However, we can envision a situation where repeated connection cycles made using a 1 mm M8 connector can weaken the connector spring tension causing less than ideal contact. This is especially true if the 1 mm is replaced with a 0.6 mm pin.

Tech Tip: The pin diameter is often omitted from connector datasheets. Consequently, there is value using the manufacturer’s recommended accessories.

Figure 2: The TE Connectivity Erni 224152-E clearly shows the pins for an A-coded M8 connection.

Best wishes,

APDahlen

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About this author

Aaron Dahlen, LCDR USCG (Ret.), serves as an application engineer at DigiKey. He has a unique electronics and automation foundation built over a 27-year military career as a technician and engineer which was further enhanced by 12 years of teaching (interwoven). With an MSEE degree from Minnesota State University, Mankato, Dahlen has taught in an ABET-accredited EE program, served as the program coordinator for an EET program, and taught component-level repair to military electronics technicians. Dahlen has returned to his Northern Minnesota home and thoroughly enjoys researching and writing articles such as this.