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Armoured Cable Glands

Why Do We Use Cable Glands?
- To firmly secure cable entering a piece of equipment
- To maintain the ingress protection of the piece of equipment (minimum of IP54 for 'e' and 'n' type enclosures. Where the enclosure wall thickness is less than 6mm a sealing washer or thread sealant will be required to maintain IP54 protection)
- To maintain earth continuity between a piece of equipment and any armouring in the cable
- To ensure containment of an internal explosion in flameproof equipment
 
Is There a British Standard for Cable Glands?
The Code of Practice for selection, installation and inspection of cable glands used in electrical installations is covered in BS 6121-5 1989 Mechanical cable glands.
 
Selecting Cable Glands
Items to consider when selecting a cable gland for a particular installation include:
- Possibility of electrolytic action between the gland and the enclosure. Shortened lifetime for the glands and the cable entries can result if incompatible materials selected. The most common materials used are brass, stainless steel and plastic. Material choice will influence cost.
- Degree of Ingress Protection required. See our page on IP ratings.
- Certification of gland for use in Hazardous areas
- Normal or barrier gland required
- Size of cable being terminated
- Size of cable entry on piece of equipment
 
What is a Barrier Gland?
Barrier glands are similar to normal glands, except a compound sealant material is used to ensure the inside of the cable is gas tight as well as the outside.
 
When Should a Barrier Gland be Used?
BS EN60079-14 Electrical Apparatus for Explosive Gas Atmospheres Part 14 - Electrical Installations in Hazardous Areas (other than Mines) provides a selection process for deciding if a barrier gland is required. There are various options to consider, however if the hazardous gas require IIC apparatus, or if the volume of the enclosure is greater than 2 litres then it is likely you will need to use a barrier gland. IIC apparatus is generally associated with Hydrogen.
 
Gable Gland Sizing
A rough gland sizing table is provided below, however reference should be made to the British Standard referenced above.
 

Nominal Conductor
Area (mm2)

Number of cores

1 2 3 4 5 7 10 12 19 27 37 48
1.5 -- 20S 20S 20S 20S 20S 20 25 25 25 32 32
2.5 -- 20S 20S 20S 20 20 25 25 25 32 41 40
4 -- 20S 20S 20 20 20 25 25 32 40 -- --
6 -- 20 20 20

This chart is for guidance only.
 
Consult relevant British Standards before making final selection.

10 -- 20 25 25
16 -- 25 25 25
25 -- 25 25 32
35 -- 25 32 32
50 20 32 32 40
70 25 32 40 40
95 25 40 40 50
120 25 40 50 50
150 32 50 50 63
185 32 50 50 63
240 40 50 63 63
300 40 63 63 75
400 50 63 75 --

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Further Reading


 
17th Edition IEE Wiring Regulations: Explained and Illustrated
 
Practical Electrical Equipment and Installations in Hazardous Areas
brass cable gland
 

C&I Resources

 
ATEX
Cable Gland Selector
CE Marking
Flange Dimensions
Ingress Protection
Pipe Schedules
Relief Valve Orifice Size
Temperature Class
Temperature Conversion
Thermocouple Types
Valve Leakage
Vortex Meters
Wires and Cables
 

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