A chain is only as strong as its weakest link. And for industrial electronic enclosures that can mean the cable glands. Here’s how to specify the right one for your enclosures…
ROLEC recommends nickel-plated brass cable glands for diecast aluminum enclosures or stainless steel cases. Specify Polyamide (PA) glands for non-metal enclosures manufactured from glass reinforced polyester (GRP), UV-stable Luran or ABS.
All ROLEC enclosures are destined for demanding outdoor or industrial environments so the glands we supply are designed to cope with the toughest conditions that nature or humanity can throw at them.
Even the most watertight enclosure will fail if you specify the wrong cable gland. Water – especially if it’s under pressure – will find a way in if your cable glands are not up to the job.
The nickel-plated brass cable glands we supply are either IP 68 (Neoprene gasket) or IP 65 (threaded O-ring gasket)/IP 54 (soft rubber gasket).
Do not underestimate the power of polyamide plastic – our plastic cable glands are just as watertight as our nickel-plated brass ones (IP 68/5 bar).
But ingress protection is not the complete story. You will need to think about IP ratings when considering temperature stability as well. Contact ROLEC for more information about which IP ratings are best for your chosen applications.
For most cable diameters this should not be an issue. For most metric cable glands there will be a PG equivalent in the ROLEC range. But not always…
If you need to accommodate larger cables then it pays to specify metric cable glands. For IP 68/5 bar nickel-plated brass cable glands, the largest size is M63 (clamping diameter 32-48 mm) but the biggest PG size is PG42 (clamping diameter 35-45 mm).
And the largest EMC gland (M63) offers a clamping diameter of 34-44 mm while the biggest EMC PG gland is PG29 (clamping diameter 18-25 mm).
Ultimately, opting for metric offers you a wider choice of clamping diameters.
Also, you may also need to relieve pressure within your enclosures. Bear in mind that our plastic (polyamide) pressure compensating elements (IP 66) are available only with an M12 thread. That is another reason to go for metric instead of PG. After all, why mix threads on your enclosures?
Remember that earlier reference to the weakest link in the chain? There’s no point specifying ultra-tough cable glands if movement damages the cable and exposes your electronics to the risks of short circuits or water and/or dust ingress.
Specify cable glands with built-in strain relief and bending protection – but bear in mind that you will be looking at plastic (polyamide) rather than metal cable glands.
It is also important to note that the choice of sizes for cable glands with strain relief can be more limited. For ROLEC that means M16, M20, M21 or M25 – cable diameters from 6-8, 8-10, 10-12 and 12-14 mm – and no PG threads.
Locknuts may be the only way to secure your cable glands in place if your enclosure walls are too thin to tap. So make sure you specify good ones – they may be the only thing that stands between your PCBs and the threat of water ingress.
The thickness of your case wall will decide whether you need a locknut…which in turn will play a role in determining the size of your cable glands.
ROLEC offers locknuts in nickel-plated brass (M10-M63/PG7-PG29) and polyamide (M12-M63/PG7-PG42).
Download the ROLEC catalog for full specifications of all ROLEC enclosures and accessories (including cable glands).
Contact ROLEC for more advice – and ask us for a sample.