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.
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According to IEC 61076-2-104, the M8 connectors may have male pins with diameters of 0.6, 0.7, and 1 mm.
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According to IEC 61076-2-111:2017, the M12 connectors may have male pins with diameters of 1.0 and 1.5 mm.
This article is part of the DigiKey Field Guide for Industrial Automation
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Author: Aaron Dahlen | MSEE | Senior Applications Engineer, DigiKey
Last update: 09 Mar 2026
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.), is a Senior Applications Engineer at DigiKey in Thief River Falls. His background in electronics and industrial automation was shaped by a 27-year military career as both technician and engineer, followed by over a decade of teaching.
Dahlen holds an MSEE from Minnesota State University, Mankato. He has taught in an ABET-accredited electrical engineering program, served as coordinator of an electronic engineering technology program, and instructed military technicians in component-level repair.
Today, he has returned to his home in northern Minnesota, completing a decades-long journey that began with a search for capacitors. Read his story here.