An M20 cable gland is a type of cable management device used to secure and protect cables and wires as they pass through an opening in an electrical enclosure, junction box, or similar equipment. The "M20" in the term refers to the metric thread size of the cable gland, which is often used as a standard reference for specifying the size of the cable entry point.

The cable gland typically consists of several components, including a threaded body, a sealing element, a locking nut, and sometimes a washer. The threaded body is inserted through a hole in the enclosure, and the sealing element (usually made of rubber or other flexible materials) is compressed against the cables to provide a water-tight and dust-tight seal. The locking nut is then tightened onto the threaded body to secure the cable gland in place and maintain the integrity of the seal.

Cable glands are essential for various applications, such as industrial machinery, control panels, outdoor electrical installations, and more, where cables need to be protected from environmental factors like moisture, dust, and even physical strain. Different sizes of cable glands, like the M20, are available to accommodate different cable diameters and thread sizes.