What are M8 connectors?

By AJ Born | October 24, 2023

Meet the Connector: M8 Connector

Due to their design and functionality, as well as compact size and reliable connectivity, M8 connectors play a crucial role in a wide range of industries, from industrial automation to automotive applications. M8 connectors are commonly used in industrial settings as sensor and actuator connections. With an 8 mm locking thread, they are smaller than M12 connectors, making them ideal for applications that require a lightweight connector or those that have limited space.

“One of the most notable attributes of the M8 connector is its robust design,” said Brian Wang, field application engineer with JPC Connectivity.

M8 connectors

JPC Connectivity’s M8 connectors are extruded and often used in harsh environments where exposure to moisture, dust, and vibrations is an issue. The M8 connectors are engineered with sealing mechanisms that make them water-resistant and dustproof up to IP67.

Another major advantage of the M8 connector is reduced setup time, since the need for installing and maintaining a wiring system is eliminated.

Design Notes

Form Factor

The “M” in M8 stands for metric and the number “8” refers to the diameter of the connector’s thread. Its small size makes it ideal for applications where space is limited or where multiple connections need to be made in proximity.

HARTING Sensor Actuator Boxes, available through Mouser Electronics, feature an extensive range of passive I/O distributor boxes for applications such as automation, robotics, and process systems. These modules enable faster installation and reduce the number of cable lengths required between the sensors and the control cabinet. Sensors can be quickly and easily connected to passive distributor boxes via standard M8 and M12 slots. With a choice of four, eight, or 10 slots, the sensor cables do not have to be drawn from the sensor into the control cabinet, but only to the local, application-led distributor box. A master line to the control cabinet takes care of the rest. 

Variety of Configurations

M8 connectors come in a variety of configurations, including male and female, straight and angled, and 3-, 4-, and 5-pin versions.

How to Specify

  • Number of pins (3-pin, 4-pin, and 5-pin configurations) depends on the application.
  • Coding, indicated by a letter on the connector (most commonly A, B, and D) prevents mismating.
  • Termination is screw termination, panel mount, solder, or crimp.
  • Shell material is typically nickel-plated brass or stainless steel, depending on the environmental conditions in which the connector will be used.
  • Mating is typically with either overmolded cable assemblies or panel jacks. The mating connector should be compatible with the specific M8 connector being used.

TE Connectivity’s M8 Hybrid solution, available from Avnet. The M8 Hybrid allows for a single open, scalable Ethernet-based network within automation systems. It standardizes the transmission of Ethernet over only one pair of copper wires. In addition to data transmission via SPE, the M8 Hybrid solution also provides power transmission over a separate wire pair. Data transmission is possible up to 1 Gb/s, and power supply up to 400 W. At 10 Mb/s speed transmission distances up to 1,000 meters are possible.


The compact size of the M8 connector makes it particularly suitable for space-constrained applications like factory automation machinery. In industrial automation, M8 connectors are commonly used to connect sensors, switches, actuators, PLCs, I/O boxes, and other components in industrial machinery, such as food and beverage processing, machine building, rubber and plastics, textile and printing presses, and in HVAC system valves. M8 connectors are found in RFID readers used in rail and industrial markets. In the automotive industry M8 connectors are used in lighting, sensors, and onboard electronics.

“The M8 connector’s ability to provide a secure connection in tight spaces and withstand the rigors of the road makes it an essential component in modern vehicles,” said Wang. “The M8 showcases its unique compact design and robust functionality. Its versatility and durability make it an indispensable component in industries that demand reliable connections in challenging environments. As technology continues to advance, the M8 connector’s role is likely to expand even further across various sectors.”

TE Connectivity’s field installable M8 connector. The M8 connector is used specifically with industrial sensors and features a waterproof 3-pin screw. Typically used in harsh environments, these connectors come pre-assembled and remain watertight even if submerged. A major advantage of using the M8 connector, as well as the M12 connector, is the time saved in installing wiring systems and maintaining it. This reduces setup time and eliminates the need for electricians or technicians.

Suppliers: Amphenol LTW, binder, Belden, JPC Connectivity, HARTING, Lumberg Automation, Molex, Neutrik, NorComp, Phoenix Contact, TE Connectivity, Weidmüller, Würth Elektronik

Like this article? Check out our other Meet the Connector and Connectors articles, our Sensors/Antennas Market Page, and our 2023 and Article Archive

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AJ Born
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