Mounting rail

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Electrical components mounted on DIN rails (TH 35), " top-hat rail mounting"

A mounting rail , also known as a DIN rail , is a universal support made of a sheet metal profile (rarely also made of plastic) in electrical engineering for fastening electrical equipment in distribution boxes , switch cabinets , junction boxes , etc.

On a support rail different components (for example, relays , impulse switches , switches , breakers , terminal blocks) are laterally pushed or plugged from the front and locked. The assembly of control cabinets and switch boxes is made easier by this standardized method, which reduces labor costs. The different types of rails are in the norm

DIN EN 60715: 2018-07 (Dimensions of low-voltage switchgear - standardized mounting rails for the mechanical fastening of electrical devices in switchgear)

summarized standardized. Before 2018 the standard DIN EN 60715: 2001-09 was in effect, which in turn replaced the older standards DIN EN 50022 ... 50024, DIN EN 50035 and DIN EN 50045 in 2001.

Executions

The material used is steel (galvanized, chromated), copper or aluminum . In addition to their load-bearing function, mounting rails made of copper or aluminum can also be used as protective conductors (PE conductors) or PEN conductors ; Steel may be used as a PE rail, but not as a PEN rail because of its poor electrical conductivity .

Top hat rail

Relay for TH-35 top-hat rail mounting

The top hat rail (TH 35, formerly TS 35) is a support rail with a top hat profile.

The profile is cold rolled from sheet steel or extruded from an aluminum alloy . Long holes are often punched out in the middle of the profile.

DIN rails are 35 mm wide and 7.5 or 15 mm high. The material thickness (sheet thickness) is 1 mm.

In English, the top-hat rail is usually referred to as a DIN rail; This means in particular the 35 mm × 7.5 mm variant, the middle one in the following figure.

DIN rail profile

The built-in devices (often referred to as rail-mounted devices, or REG for short) are placed with a clamping mechanism on the top-hat rail, which is fastened horizontally to a vertical wall. The size of the device housings are standardized, the dimensions being essentially determined by the shape of the fronts of the distribution boxes .

The width of the devices follows a grid of 18 mm called a division unit.

The depth of the protruding device housing must be min. 70 mm. The front of the devices has a height of 45 mm (corresponding to the height of the opening in the front of the housing). The height of the protruding devices must not increase for the first 26 mm in the depth direction. The height from the top-hat rail is max. 85 mm.

The REG units (devices) are snapped onto the rail and can therefore be easily moved. That is why there are stoppers that prevent sideways movement. Protective conductor terminals and stoppers are often additionally secured with screws.

The locking mechanism is only available on one side, which is why the fixed part of the locking profile of the housing must first be hung over the edge of the rail when locking.

The locking mechanisms are made of plastic or metal and require a tool to pull back the locking mechanism to snap on, or at least to release.

Devices that are built far to the rear next to the duct have a bevel on the rear side on the side of the fixed locking profile in order to allow tilted hooking into the rail.

The movable nose and its actuation mechanism are usually on top (in the wall mounting orientation), but sometimes also on the bottom.

G-rail

A G-rail (G 32) is a mounting rail with a G-shaped profile.

G-rail according to EN 50035 (G32)

While on the top- hat rails the bar and the movable nose of the device reach under the hat brim from the outside , on other devices the same formations reach under the profile edges of the G-rail from the inside .

Profile dimensions

DIN EN 60715 from 2001 standardized the following rail profiles:

  • TH 15 / 5.5 (total width 15 mm, hat width 10.5 mm, height 5.5 mm)
  • TH 35 / 7.5 (1 mm sheet thickness, total width 35 mm, hat width 27 mm, height 7.5 mm) (also: variant with 2.3 mm sheet thickness)
  • TH 35/15 × 1.5 (1.5 mm sheet thickness, total width 35 mm, hat width 27 mm, height 15 mm)
  • G 32 / 9x5 / 15x10.5 (G-rail with 32 mm total width, 15 mm total height)

Individual evidence

  1. DIN 43880: 1988-12 built-in installation devices; Envelope dimensions and associated installation dimensions.
  2. Profile rail cutter PSG 5 kabeltechnik.at, catalog page, accessed June 19, 2019.

literature

  • Wolfgang E. Schmidt: Learning situations energy and building technology for electronics technicians and electrical installers. 1st edition, Verlag Handwerk und Technik GmbH, Hamburg, 2005, ISBN 3-582-03671-5 .

Web links

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