Division unit

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A division unit ( TE , English division units ( DU )) is a unit of measurement for describing the width of assemblies and equipment in electrical engineering .

Division unit for electronic assemblies

In general, the dimensions of cabinets, subracks and assemblies are given in inches (1 inch = 2.54 cm). A unit of division in electronic assemblies corresponds to 1 ⁄ 5  inches, i.e. 5.08  mm . This means that the dividing unit fits the grid dimension of 2.54 mm that is usual for printed circuit boards and electrical components .

Subrack

Subrack with guide rails for subassemblies with four TE

The width of the modules is specified with the pitch unit so that the possible number of modules can be determined when planning a module rack. Based on a 19 ″ subrack with a usable width of approx. 427 mm, there are 84 modules. The picture shows a section of a 19 ″ subrack with six height units . On the right side there is a standard assembly with a width of four modules (4 × 5.08 mm = 20.32 mm). The guide rails are inserted in every fourth notch and thus have the right distance for further standard assemblies. Assemblies with more or fewer modules require a different distance between the guide rails. With the guide rails used here, 42 modules, each with two modules wide, can be used in a standard 19 ″ module rack.

Electrical installation and switch cabinet construction

Two single-pole LS-switches with a width of one module each
Electrical distributor with built-in devices of various widths

In electrical installation and control cabinet construction , the width of built-in devices such as miniature circuit breakers , residual current circuit breakers , etc. is specified in modules, the width of a module is 18 mm. According to the DIN 43880: 1988-12 standard, the installation width of the device should be between 17.5 and 18.0 mm, or it should be calculated by multiplying this dimension by 0.5 or an integral multiple thereof, i.e. k 0.5 18 mm or k · 0.5 · 17.5 mm (with k = 1, 2, 3, ...). For example, a single-pole circuit breaker has a width of 1 module. The built-in electrical installation distributors are matched to the distribution units according to DIN 43871 “Small installation distributors for built-in devices up to 63 A ”, e.g. B. the width of the mounting rails .

The partition unit is a module and is sometimes also called a space unit (PLE).

Usual modules

usual modules
TE Max. Width
in mm 		Examples of frequently used DIN rail mounted devices
0.5 9
  • Add-on elements: auxiliary switch, fault signal switch
1 18th
  • single-pole circuit breaker 1P (≤ 63 A)
  • single-pole circuit breaker 1P + N, compact (≤ 40 A)
  • single / double pole surge protection
1.5 27
  • single-pole circuit breaker 1P (63–125 A)
  • single Neozed base
  • single-pole circuit breaker 1P + N
2 36
  • two-pole circuit breaker 2P (≤ 63 A)
  • single-pole circuit breaker 1P + N (≤ 63 A)
  • Residual current circuit breaker 1P + N (mostly ≤ 63 A)
  • FI / LS switch 1P + N (≤ 40 A)
  • two- / four-pole overvoltage protection
2.5 45
3 54
  • three-pole circuit breaker 3P (≤ 63 A)
  • Overvoltage protection
4th 72
  • three-pole circuit breaker 3P + N (≤ 63 A)
  • Residual current circuit breaker 3P + N (mostly ≤ 100 A)
  • Overvoltage protection
4.5 81
  • triple neozed base
6th 108
  • Overvoltage protection
8th 144
  • Overvoltage protection

Applications

Individual evidence

  1. ↑ Standard DIN 43880 : 1988-12 built-in installation devices ; Envelope dimensions and associated installation dimensions, page 4, section 3.3: "The division unit a is 18 mm."
  2. ↑ DIN-rail devices, power distribution & metering systems | hager.at. Hager , accessed August 27, 2018 .
  3. ↑ Low-voltage power distribution and electrical installation technology. (PDF; 317 MB) Catalog LV 10. Siemens , April 2018, accessed on August 27, 2018 .
  4. ↑ DIN rail mounted devices | Schneider Electric. Schneider Electric , accessed August 27, 2018 .