Cable gland

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Logo of the German Institute for Standardization DIN EN 60423
Area Electrical installation
title Electrical installation pipe systems for electrical energy and for information - outer diameter of electrical installation pipes and threads for electrical installation pipes and their accessories
Latest edition 2008-07
ISO

A cable gland is a cable entry that offers a particularly good seal for a cable, a line or an insulated conductor when it passes through a housing wall or a bulkhead. You can also use other functions, such as B. functional grounding (equipotential bonding), insulation, kink protection, strain relief or a combination of these.

General

Cable glands on a rotary actuator for slide valves in Melk, Austria
Different sizes of cable glands

A cable gland protects electrical equipment ( e.g. switch cabinet , junction box ) from mechanical influences, dust and moisture by connecting a cable tightly and tightly to the housing. Today metric threads according to DIN EN 60423 are mandatory. Cable glands with armored steel pipe threads (PG), so-called PG cable glands and, especially in the American market, the self-sealing NPT thread, are also used .

Modern cable glands were born in the mid-1960s, when Otto Pflitsch from Hückeswagen developed a “gland-like introduction of electrical cables” and applied for a patent (German Patent Office, patent number 1 263 134, granted on July 3, 1966). With the first cable glands, a rubber ring was squeezed onto the cable when the pressure screw was tightened and provided a seal. After the introduction of industrial plastics, the rubber ring was supplemented by clamping lamellae in order to increase the strain relief. However, this can lead to constrictions in the cable jacket, which in the long term reduces the tightness.

Otto and Harald Pflitsch developed an alternative to this at the end of the 1960s with a cable gland in which a large sealing insert is softly squeezed onto the cable.

For EMC- compliant installation, the brass cable glands can be supplemented with EMC inserts, which saves the need to keep special EMC cable glands separately. The special solutions include hygienic cable glands made of stainless steel and plastic - certified according to EHEDG for the food industry - with smooth, rounded surfaces and gap-free assembly, which prevent pollution nests and are easy to clean. Cable glands with special sealing inserts, which must withstand fire and smoke for at least 15 minutes, ensure fire protection in rail traffic according to EN 45545-2.

In addition, a minimum degree of protection of IP54 is required for cable glands . Market conditions, are degrees of protection as IP65 / IP66 (dust and water jet protected) and IP68 / IP69K (dustproof and waterproof) for the protection of people against potential dangers when using them available.

In contrast to the grommet , which only seals, the cable gland fixes the cable.

For pre-assembled with connector cable is divisible cable glands are suitable. A cable and line bushing device is an insertion device, provided for one or more cables and lines, with a seal of one or more separate components made of an elastomer or parts of components (modular inner seal), which are pressed together as soon as the device is assembled and is mounted as intended. Single screw connections as well as flange systems with several integrated cable screw connections are available. Depending on the model, these divisible cable glands can achieve degrees of protection up to IP66 / IP68.

Depending on the application, cable glands with a brush seal can also be used. However, since these do not meet the requirements of IP68 / IP69K, but merely shield against dust and drafts, they are primarily suitable for the introduction of cables into network cabinets, switch boxes or control cabinets.

Cable and line feed-through devices can also serve as Ex-sealing plugs if the components made of elastomer are intended for this function. (Source: DIN EN 60079-0 (VDE 0170-1): 2014-06) These consist of a total of three parts, the two-part screw connection body and a slotted sealing element. Pre-assembled cables can be inserted without having to unsolder the plugs. Alternatively, divisible cable entry systems can also be used. These make it possible to insert and seal a large number of pre-assembled cables.

Technical specifications

Divisible cable gland for the introduction of pre-assembled cables

The usual sizes and thread types of cable glands according to DIN EN 60423 are listed below:

Nominal size Outside
diameter
(in mm) 		pitch Bore
diameter
(in mm)
Metric thread
M6 x 0.75 6.0 0.75 6.0 + 0.2
M8 × 1 8.0 1.0 8.0 + 0.2
M10 × 1 10.0 1.0 10.0 + 0.2
M12 × 1.5 12.0 1.5 12.0 + 0.2
M16 × 1.5 16.0 1.5 16.0 + 0.2
M20 × 1.5 20.0 1.5 20.0 + 0.2
M25 × 1.5 25.0 1.5 25.0 + 0.2
M32 × 1.5 32.0 1.5 32.0 + 0.3
M40 × 1.5 40.0 1.5 40.0 + 0.3
M50 × 1.5 50.0 1.5 50.0 + 0.4
M63 × 1.5 63.0 1.5 63.0 + 0.4
M75 × 1.5 80.0 2.0 75.0 + 0.5
M90 × 2.0 90.0 2.0 90.0 + 0.5
M110 x 2.0 110.0 2.0 110.0-0.5
PG thread
PG 7 12.5 1.27 13.0 ± 0.2
PG 9 15.2 1.41 15.7 ± 0.2
PG 11 18.6 1.41 19.0 ± 0.2
PG 13.5 20.4 1.41 21.0 ± 0.2
PG 16 22.5 1.41 23.0 ± 0.2
PG 21 28.3 1.558 28.8 ± 0.2
PG 29 37.0 1.558 37.5 ± 0.3
PG 36 47.0 1.558 47.5 ± 0.3
PG 42 54.0 1.558 54.5 ± 0.3
PG 48 59.3 1.558 59.8 ± 0.3
NPT thread
NPT 1 ⁄ 4 ″ 13.7 1.41 14.1-0.2
NPT 3 ⁄ 8 ″ 17.1 1.41 17.4-0.2
NPT 1 ⁄ 2 ″ 21.3 1.81 21.6-0.2
NPT 3 ⁄ 4 ″ 26.7 1.81 27.0-0.2
NPT 1 ″ 33.4 2.21 33.7-0.2
NPT 1 1 ⁄ 4 ″ 42.2 2.21 42.5-0.2
NPT 1 1 ⁄ 2 ″ 48.3 2.21 48.7-0.2
NPT 2 ″ 60.3 2.21 60.7-0.2

Detachment of the PG thread

The PG cable glands with armored thread according to DIN standard DIN 46320 (replaced by DIN EN 50262, now replaced by DIN EN 62444), which are common for cable glands in the German-speaking area, are only permitted in exceptional cases for new cable glands and are increasingly being replaced by metric threads . Ten old PG sizes have now been replaced by eight new metric sizes. A one-to-one assignment is not possible.

Changeover from PG
to metric thread
old (DIN 40430) new (EN 60423)
PG 7 M12 × 1.5
PG 9 M16 × 1.5
PG 11 M20 × 1.5
PG 13.5
PG 16 M25 × 1.5
PG 21 M32 × 1.5
PG 29
PG 36 M40 × 1.5
PG 42 M50 × 1.5
PG 48 M63 × 1.5

Individual evidence

  1. ↑ DIN EN 62444 (VDE 0619: 2014-05) cable glands for electrical installations
  2. ↑ Cable glands with brush strips. Accessed January 30, 2019 .
  3. ↑ DIN 40430 from Beuth-Verlag

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