Choosing the right cable gland can be a challenging task for many engineers and technicians. With numerous
specifications and parameters to consider, selecting an incorrect model can compromise electrical performance or
even create safety hazards. This comprehensive guide examines the critical factors in cable gland selection,
particularly focusing on size considerations for armored and non-armored variants.
Understanding Cable Glands: Essential Components for Electrical Systems
Cable glands, also known as cable connectors or cable fittings, serve as vital components in electrical
installations. These devices perform multiple critical functions:
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Securing cables firmly in place
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Providing mechanical protection
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Ensuring reliable electrical connections
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Preventing ingress of dust, moisture, and other environmental contaminants
Proper selection of cable glands is comparable to fitting cables with precisely tailored protective
gear—essential for maintaining system integrity and safety.
Primary Cable Gland Classifications: Armored vs. Non-Armored
Armored Cable Glands
Designed specifically for use with armored cables featuring metal protective layers (typically steel tape or
wire braiding), these glands provide:
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Reliable grounding of the cable armor
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Enhanced mechanical fixation
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Superior protection against electromagnetic interference
Non-Armored Cable Glands
Used with standard cables lacking metal protective layers, these glands offer:
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Secure cable retention
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Environmental sealing
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Protection against mechanical damage
Critical Parameters for Cable Gland Selection
Proper sizing is essential for both armored and non-armored cable glands. Incorrect sizing can lead to insecure
connections, compromised sealing, or installation difficulties. Key parameters include:
Universal Parameters (Both Gland Types)
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Cable Outer Diameter:
The primary sizing reference, must fall within the gland's specified range
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Entry Thread Size:
Must match the equipment's threaded entry point (Metric or NPT standards)
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Thread Length:
Affects connection security and sealing performance
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Across Flats/Diagonal Width:
Determines required wrench size for installation
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Protrusion Length:
Important for space-constrained installations
Armored Gland-Specific Parameters
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Cable Bedding Diameter:
Diameter beneath the armor layer
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Armor Range:
Thickness of the cable's armored layer
Practical Selection Examples
Armored Cable Gland Selection (T3CDS Series Example)
For an armored cable with these specifications:
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Bedding diameter: 20mm
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Outer diameter: 12mm
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Armor thickness: 0.5mm
The T3CDS series offers suitable options:
|
Gland Size
|
Thread
|
Bedding Diameter Range (mm)
|
Outer Diameter Range (mm)
|
Armor Range (mm)
|
|
20S
|
M20
|
15.0-19.9
|
6.1-15.9
|
0.3-1.0
|
|
20
|
M20
|
15.0-19.9
|
6.5-20.9
|
0.4-1.0
|
Non-Armored Cable Gland Selection (A2F Series Example)
For a non-armored cable with 18mm outer diameter:
The A2F series 25 model provides appropriate compatibility:
|
Gland Size
|
Thread
|
Outer Diameter Range (mm)
|
|
25
|
M25
|
11.1-20.0
|
Additional Selection Considerations
Beyond dimensional parameters, several environmental and application factors influence gland selection:
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Environmental Conditions:
Consider IP ratings for moisture/dust protection
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Cable Composition:
Special materials may require specific sealing compounds
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Explosion Protection:
Hazardous areas demand ATEX/IECEx certified glands
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Temperature Range:
Verify operational temperature specifications
Conclusion
Proper cable gland selection forms a critical component of electrical system design and installation. By
understanding the fundamental differences between armored and non-armored variants, carefully evaluating
dimensional parameters, and considering environmental factors, professionals can ensure reliable, safe
electrical connections. The appropriate cable gland serves as both protective barrier and mechanical anchor,
contributing significantly to system longevity and performance.
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