Cable Gland Selection Guide: Thread, IP Rating & Armoured Cable Compatibility
Get a cable gland wrong and the failure shows up later, not immediately — as water ingress six months on, a stripped thread on installation, or an armoured cable's steel wire braid left without a proper earth continuity path. Three things decide whether a gland is right for the job: the thread type matching the enclosure entry, the clamping range matching the actual cable outer diameter, and — for armoured cable — a construction that properly terminates and earths the armour rather than just gripping the outer sheath.
This guide walks through all three, plus IP rating and material selection, so you can specify the right gland the first time rather than discovering a mismatch on site.
What a Gland Actually Has to Do
A cable gland has three jobs at once: seal the cable entry against dust and water ingress to maintain the enclosure's IP rating, mechanically clamp and strain-relieve the cable so pulling on it doesn't stress the terminations inside, and — on armoured cable — provide a continuous, low-resistance earth path from the cable's armour or braid through to the enclosure. A gland that only does the first two jobs but leaves the armour unterminated or poorly earthed has quietly removed a safety-critical fault path without anyone noticing until there's a fault to clear.
Common Gland Materials
| Material | Best For |
|---|---|
| Nylon (polyamide) | General indoor/outdoor use, cost-effective, good chemical resistance |
| Brass (plated) | Higher mechanical strength, better earth continuity on armoured cable |
| Stainless steel | Corrosive, marine, washdown or high-temperature environments |
Four Things to Confirm Before You Order
Thread Type Matching the Enclosure Entry
Metric (M16, M20, M25, M32...), NPT (American tapered thread), and PG (an older European standard still common on legacy equipment) are not interchangeable, even when a thread "almost" seems to fit. Forcing an NPT gland into a metric entry, or vice versa, cross-threads the enclosure and destroys the seal even before the gland is fully tightened. Confirm the enclosure's thread standard first — it's stamped on most enclosures near the entry, or specified on the enclosure's own datasheet.
Clamping Range Matching the Actual Cable OD
Every gland has a stated minimum and maximum cable outer diameter it can seal effectively — sizing on the actual measured cable OD, not the nominal size printed on the cable's own datasheet, since real-world tolerances vary between manufacturers and cable types. A gland clamped at the very edge of its range rarely seals as reliably as one sized comfortably within it.
Armoured vs Unarmoured Construction
A standard unarmoured gland only clamps the cable's outer sheath and has no provision for the steel wire armour on SWA cable — using one on armoured cable leaves the armour loose inside the gland with no proper earth continuity path, which is a real fault-clearance and safety issue, not just a mechanical weak point. Armoured cable needs a gland specifically built with an inner cone and armour clamping ring designed for that purpose.
IP Rating Matching the Enclosure and Environment
A gland's IP rating should match or exceed the enclosure it's fitted to — an IP68-rated enclosure fitted with an IP66 gland only achieves IP66 overall at that entry point. Outdoor, washdown, or submerged installations need the gland rating confirmed against the actual worst-case exposure the cable entry will see, not just the general area classification.
Frequently Asked Questions
Can I use a reducer or adaptor to fit a gland with the wrong thread type?
Thread adaptors exist and can work as a short-term fix, but each additional joint is another potential leak path and reduces the overall assembly's effective IP rating to whatever the weakest joint achieves. Specifying the correct thread from the start is always the more reliable option.
Do I need a separate earth tag if the gland already terminates the armour?
Depends on the design and site standard — many armoured gland kits include a separate earth tag as an additional bonding point back to the earthing system, on top of the gland's own armour clamp, particularly where local wiring regulations or the enclosure design call for a dedicated earth conductor termination.
What's the risk of over-tightening a gland?
Over-tightening can crush or damage the cable's outer sheath, and on some designs can distort the sealing ring enough to actually reduce sealing effectiveness rather than improve it. Torque to the manufacturer's specification rather than "as tight as it'll go."
Are glands rated for hazardous (ATEX) areas different from standard glands?
Yes — ATEX/hazardous area glands are certified to specific protection concepts (Ex e, Ex d, etc.) with construction and testing standards well beyond a standard IP-rated gland, and using a standard gland in a classified hazardous area is a compliance and safety failure, not just a spec mismatch.
Can the same gland be reused if a cable is replaced?
Only if the seal, clamping components and threads are all undamaged from the original installation, and the new cable's OD is still within the gland's rated range — in practice, a new seal or a full new gland is often cheaper and more reliable than risking a compromised reused seal.
Related Reading
Shop the Parts
| Product | Use | Link |
|---|---|---|
| ABB Nylon Cable Gland, M16 Thread, 5-10mm, IP68/IP69 | General-purpose sealing on smaller cables | View product → |
| ABB Stainless Steel Cable Gland, 1/2in NPT Thread | Corrosive, marine or washdown environments with NPT entries | View product → |
| ABB NPG Series Nylon Cable Gland, M32 Thread | Larger cable diameters, general indoor/outdoor use | View product → |
| Full cable gland range | Browse by thread type, clamping range and IP rating | Browse cable glands → |
| All genuine ABB products | Cable glands, terminal accessories and enclosure hardware from the same manufacturer | View all ABB products → |
Disclaimer: ABB, and any other manufacturer or brand names referenced in this article, are used solely for identification and compatibility purposes. Z&F Corporation is not affiliated with, authorised by, or an official representative of these manufacturers; all trademarks are the property of their respective owners.