Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Electrical engineering and control panels

DIN rail

Also known as: Top-hat rail, TS 35 rail, Mounting rail

German: Hutschiene

In control panel building, a DIN rail is a standardized metal rail, most commonly 35 mm wide with a top-hat profile, on which terminal blocks, circuit breakers, relays, power supplies and I/O modules are snapped in a control cabinet.

  • Control panels

In one sentence

A DIN rail is a standardized metal rail, usually 35 mm top-hat, for mounting terminals, breakers, relays and modules in cabinets.

Example

The panel builder snaps the power supply, circuit breakers and terminal blocks onto 35 mm DIN rails on the mounting plate.

How it applies

  • Engineering: IEC 60715 specifies rail dimensions, including 35 mm top-hat rails in 7.5 mm and 15 mm heights. Heavy devices may need the deeper rail or additional fastening. Some devices use the rail for grounding; that must be designed deliberately, not assumed.
  • Installation: Leave space at rail ends for end stops and later additions, and follow the device manufacturer's minimum spacing for heat dissipation.
  • Documentation: Cabinet layout drawings show rail positions and device order. "DIN rail" is the common name, but the defining standard is IEC 60715 (formerly EN 50022 for the 35 mm rail).

DIN rail vs. mounting plate

The mounting plate is the metal back panel of the cabinet. DIN rails are fixed on it and carry the modular devices; larger devices are screwed directly onto the plate.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: IEC 60715, Dimensions of low-voltage switchgear and controlgear — Standardized mounting on rails for mechanical support of switchgear, controlgear and accessories

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Blog and are not part of any standard.

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