How to choose cable glands by material, ingress rating and thread type. A buyer's guide to metric, PG and NPT glands for panels and enclosures.
A cable gland - sometimes called a cable connector or strain-relief fitting - is the mechanical seal where a cable passes through the wall of an enclosure, junction box or panel. Its job is threefold: it grips the cable's outer sheath so it cannot be pulled out, it maintains the ingress protection (IP rating) of the enclosure, and it can provide an earth or armour connection for screened or armoured cable. It is not a connector and does not carry the circuit current - the conductors inside the cable do that. Get the gland wrong and you get water ingress, loose cables, or a failed IP rating that voids the enclosure's whole protection.
The gland body material must suit the environment, not just the budget:
| Material | Best for | Notes |
|---|---|---|
| Nickel-plated brass | Indoor panels, general industrial | Good EMC shielding, cost-effective, the default choice |
| Stainless steel (A2/A4) | Wash-down, marine, chemical | Corrosion-proof; A4 for seawater |
| PA (nylon) / plastic | Light indoor, low cost, non-conductive | No EMC path; watch temperature and UV |
| Aluminium | Weight-sensitive, some outdoor | Lower cost than SS, watch galvanic corrosion |
For EMC-sensitive panels, use a brass or stainless gland with an integral EMC spring clamp that bonds the cable screen to the enclosure - a plastic gland cannot do this.
The gland's own rating must meet or exceed the enclosure's. An IP68 gland on an IP65 box is wasted; an IP54 gland on an IP68 enclosure is the weak point. Two seals matter: the outer seal that compresses against the enclosure wall (often a conical or flat rubber gasket, or a dedicated locknut with O-ring) and the inner seal (the elastomer clamping seal insert) that grips the cable jacket. For outdoor and wash-down use specify a delivered IP68 with a properly sized seal; the gland only achieves its rating when the seal matches the actual cable diameter.
The thread must match the threaded hole in your enclosure. The common standards:
Metric and PG are not interchangeable even at similar diameters (different pitch and flank), so confirm the enclosure's tapping before ordering. A mismatched gland either will not screw in or will not seal.
Every gland covers a clamping range, expressed as the cable outer-diameter (OD) it accepts, e.g. M20 x 1.5 covering 6-12 mm. Follow this order:
A cable sitting at the very edge of the range will be under-sealed at one end and over-clamped at the other. Resize rather than force it.
| Cable | Gland type | Why |
|---|---|---|
| Armoured (SWA) | Armour gland with BW/CW locknut | Bonds the armour to earth |
| Shielded / screened | EMC gland with spring clamp | Maintains screen-to-enclosure bond |
| Flat or non-round | Specialty or twin seal | Round glands only seal round cables |
| Fibre / data | Non-metallic, light grip | No electrical bond needed |
ELEHPD supplies IP68 nickel-plated brass and stainless cable glands in metric and PG threads, EMC and armoured variants, and the distribution boxes and waterproof enclosures they seal into - a complete cable-entry solution for panel builders and OEMs.
Metric (M) is the modern IEC default and the right choice for new designs; most current enclosures are tapped metric. PG survives on legacy European equipment and some existing panels. Standardise on metric for new work, but keep a small PG stock to service older boards - the two threads are not interchangeable.
No. The enclosure's IP rating is set by its own seals and gasket; a gland only maintains the rating at the cable entry. An IP68 gland on an IP54 box still leaves you at IP54. Match or exceed the enclosure rating, and seal every unused entry with a blanking plug.
Use an EMC (shielded) gland with an integral spring clamp whenever the cable screen must stay bonded to the enclosure for electromagnetic compatibility - drives, variable-frequency panels, measurement and control wiring. A plastic or plain metal gland breaks that bond and lets interference leak in or out.
Only if every cable's outer diameter falls inside that gland's published clamping range, ideally near the middle. A gland clamping 6-12 mm will not seal a 16 mm cable, and forcing it destroys the seal. Keep the correct sizes in stock rather than stretching one range.
Send the ratings, dimensions and quantities you are working to and we will confirm the closest match from the ELEHPD catalogue, the compliance documents available for it and the lead time. OEM branding, private model numbering and buyer-specific cartons are available on qualified volumes.