View source for DIN rail

{{Short description|International standard for mounting equipment}}
{{multiple image
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| image1    = Din rail.jpg
| caption1  = A front view of a populated 35&nbsp;mm DIN rail
| image2    = DIN rail rear view.JPG
| caption2  = Rear view. Note the release loops at the top of the mounted devices which unclip them.}}

A '''DIN rail''' is a metal rail of a standard type widely used for mounting [[circuit breaker]]s and industrial control equipment inside [[Enclosure (electrical)|equipment racks]]. These products are typically made from cold rolled carbon steel sheet with a [[Galvanization|zinc-plated]] or [[Chromate conversion coating|chromated]] bright surface finish. Although metallic, they are meant only for mechanical support and are not used as a [[busbar]] to conduct electric current, though they may provide a chassis [[Ground (electricity)|grounding]] connection.

The term derives from the original specifications published by [[Deutsches Institut für Normung]] (DIN) in Germany, which have since been adopted as European (EN) and international (IEC) standards.<ref>{{cite book|last1=Simpson|first1=Robert|title=Lighting Control: Technology and Applications|date=2003|publisher=Focal Press/Elsevier|location=Oxford UK|isbn=0-240-51566-8}}</ref>  The original concept was developed and implemented in Germany in 1928, and was elaborated into the present standards in the 1950s.<ref>{{cite web|url=https://site.ieee.org/npec-sc2/files/2017/06/SC-2Mgt08-2_Att9-WP_DIN-Rail.pdf|title=DIN-Rail in the Electrical Control Cabinet and Junction Box|author=Arnold Offner|website=[[IEEE]] Power and Engineering Society|author2=Phoenix Contact|date=November 12, 2008|access-date=May 31, 2018}}</ref>

==Types==
There are three major types of DIN rail:<ref>{{cite book|last1=Tickoo|first1=Sham|title=AutoCAD Electrical 2010 for Engineers|date=2010|publisher=Dorling Kindersley|location=India|isbn=978-81-317-3213-7|pages=8–46}}<!--|access-date=September 3, 2014--></ref>
* Top hat section (TH), type O, or type Ω, with hat-shaped cross section.
* C section
* G section

===Top hat rail IEC/EN 60715===
[[File:DIN-rail-dimensions.svg|120px]]

This 35 mm wide rail is widely used to mount [[circuit breaker]]s, [[relay]]s, [[programmable logic controller]]s, [[motor controller]]s, and other electrical equipment. The EN 60715 standard specifies both a 7.5&nbsp;mm (shown above) and a 15&nbsp;mm deep version, which are officially designated
* top hat rail IEC/EN 60715 – 35 × 7.5
* top hat rail IEC/EN 60715 – 35 × 15  
Some manufacturers catalogues also use the terms: Top hat section / TH / TH35 (for 35mm wide) / Type O / Type Omega (Ω).{{citation needed|date=January 2012}}

The rail is known as the TS35 rail in the USA.{{citation needed|date=February 2024}}

====Module width====

The width of devices that are mounted on a 35&nbsp;mm "top hat" DIN rail generally use "modules" as a width unit, one module being 18&nbsp;mm wide. For example, a small device (e.g. a circuit breaker) may have a width of 1 module (18&nbsp;mm wide), while a larger device may have a width of 4 modules {{nobr|1=(4 × 18 mm = 72 mm).}} Equipment enclosures also follow these module widths, so an enclosure with a DIN rail may have space for 20 modules, for example. Not all devices follow these module widths. {{citation needed|date=April 2020}}

Module widths are usually abbreviated as "M" (e.g. 4M = 4 modules) {{citation needed|date=April 2020}}. Some manufacturers (including Mean Well) use "SU" (likely stands for "standard unit", e.g. 4SU = 4 modules) {{citation needed|date=April 2020}}.

===C section===
These rails are symmetrical within the tolerances given and referenced by the norm EN 50024 (abrogated). There are four popular C section rails, C20, C30, C40 and C50. The number suffix corresponds to the overall vertical height of the rail.

[[File:C-section-rail-C30.svg|350px]]

===G section===
[[File:G-type-Din-rail.jpg|thumb|Cross section view of a G-type DIN rail, with electrical equipment mounted on it]]
G-type rail (according to EN 50035 (abrogated), BS 5825, DIN 46277-1).
::[[File:G-Schiene EN 50035 (G32).svg|300px]]
G rail is generally used to hold heavier, higher-power components.  It is mounted with the deeper side at the bottom, and equipment is hooked over the lip, then rotated until it clips into the shallower side.

==Others==
In addition to the popular 35&nbsp;mm × 7.5&nbsp;mm top-hat rail (EN 50022, BS 5584, DIN 46277-3), several less widely used types of mounting rails have also been standardized:
* Miniature top-hat rail, 15&nbsp;mm × 5.5&nbsp;mm (EN 50045, BS 6273, DIN 46277-2);
* 75&nbsp;mm wide top-hat rail (EN 50023, BS 5585);

==Related equipment==
* [[European Standard]] EN 50022: Specification for low voltage switchgear and control-gear for industrial use. Mounting rails. Top hat rails 35&nbsp;mm wide for snap-on mounting of equipment. (formerly: [[German Standard]] DIN 46277, [[British Standard]] BS 5584)
* [[International Electrotechnical Commission|IEC]] [[List of IEC standards|International Standard 60715]]: Dimensions of low-voltage switchgear and control-gear. Standardized mounting on rails for mechanical support of electrical devices in switchgear and control-gear installations.
* [[Standards Australia|Australian Standard]] AS 2756.1997: Low-voltage switchgear and controlgear - Mounting rails for mechanical support of electrical equipment.

==See also==
* [[Printed circuit board]]

==References==
{{Reflist}}

==External links==
* {{Commons category-inline}}

{{Deutsches Institut für Normung}}

[[Category:EN standards]]
[[Category:Mechanical standards]]
[[Category:Deutsches Institut für Normung|Rail]]