Explosion Proof Cable Gland Selection Guide: Material, Size & Certification
Choosing the right explosion proof cable gland requires understanding materials, sizing, thread types, and certification requirements. This comprehensive guide walks you through every factor that matters for a safe, compliant hazardous area installation.
Understanding Cable Gland Basics
An explosion proof cable gland serves two critical functions in hazardous area installations:
- Maintains the explosion proof integrity of the enclosure by preventing gas ingress and flame propagation
- Secures the cable and provides environmental protection (IP rating) against dust and water
In European Union hazardous area installations, cable glands must be certified as part of the overall equipment certification under the ATEX directive.
Material Comparison
| Material | Corrosion Resistance | Cost | Best Applications |
|---|---|---|---|
| 316 Stainless Steel | Excellent | High | Offshore, chemical plants, coastal |
| Aluminum Alloy | Good | Medium | General industrial, indoor/outdoor |
| Brass (Nickel-plated) | Moderate | Low-Medium | Standard industrial applications |
| GRP (Glass Reinforced Plastic) | Excellent | Medium | Marine, chemical, highly corrosive |
Key Takeaway
316 stainless steel costs more upfront but dramatically reduces lifetime maintenance costs in corrosive environments. Calculate total cost of ownership, not just purchase price.
Sizing: Getting the Cable Diameter Right
Cable gland sizing is critical. A gland that is too small will not seal properly; one that is too large will not grip the cable securely. Always match the gland's sealing range to your cable's outer diameter.
Key steps:
- Measure the cable outer diameter accurately (in mm)
- Check the gland's published sealing range (e.g., 8-12mm, 12-17mm)
- Select a gland where your cable diameter falls within the mid-range of the seal
- For armored cable, also verify the armor clamping range
Thread Standards
| Thread Type | Region/Standard | Common Use |
|---|---|---|
| Metric (ISO) | Europe, International | Standard for European equipment |
| NPT | USA, Americas | US hazardous area equipment |
| G (BSPP) | UK, Former British Empire | British standard equipment |
| PG | Germany (legacy) | Older European installations |
Certification Requirements
For hazardous area installations, your cable glands must carry the correct certifications:
- ATEX (European Union): Mandatory for all equipment in EU hazardous areas
- IECEx (International): Accepted in Australia, New Zealand, Canada, and many other countries
- cULus (North America): Required for US and Canadian installations under NEC and CEC
Youngly Tech cable glands carry full ATEX and IECEx certification, with cULus available on request for North American projects.
IP Rating Guide
| IP Rating | Dust Protection | Water Protection | Application |
|---|---|---|---|
| IP65 | Dust-tight | Low-pressure water jets | Standard indoor industrial |
| IP66 | Dust-tight | Powerful water jets | Outdoor, washdown, marine |
| IP67 | Dust-tight | Temporary water immersion | Wet environments, hose-down |
| IP68 | Dust-tight | Continuous water immersion | Offshore, subsea, extreme conditions |
Need Help Selecting the Right Cable Gland?
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Get a Free QuoteFrequently Asked Questions
What is the difference between NPT, metric, and G thread cable glands?
NPT (National Pipe Thread) is the US standard with a tapered thread profile. Metric threads are the European/International standard with a straight profile. G (BSPP) is the British standard with a parallel thread profile. Always match the thread type to your enclosure — mixing thread types can result in an improper seal and compromised safety.
How do I size a cable gland correctly?
Measure the cable outer diameter in millimeters and select a gland where your cable falls within the middle of the gland's published sealing range. For example, if your cable is 14mm diameter, select a gland with a range like 12-17mm rather than 8-12mm. Always verify with the manufacturer's sizing chart before ordering.
What certification is needed for EU hazardous area installations?
For EU hazardous area installations, ATEX certification is mandatory under the ATEX Directive 2014/34/EU. Cable glands must be part of the overall equipment certification or separately certified as an Ex component. IECEx certification is also accepted for international projects and often preferred for projects outside the EU.