The primary function of any cable gland is to anchor the cable securely to an electrical apparatus. Ex d (flameproof) cable glands obviously provide additional safety performance related to human life preservation in hazardous locations. Strict international testing standards (IEC 60079 series) specify pernicious performance requirements for the certification of such glands. These requirements are so demanding that, up until now, no Ex d/e corrosion-resistant flameproof compression gland on the world market has been certified without some attendant requirements or ‘special conditions’ of use. Pratley Marketing Director Eldon Kruger comments: “It is quite bizarre to pay for a cable gland that, due to its incapability of performing its primary anchoring function, requires the special condition of external clamping.”
Also, notwithstanding the extra cost, the external clamp itself must necessarily comply with IEC 61914 (2009 Ed.1). If it is either not fitted or not compliant, the entire installation would be unsafe and non-compliant. This places innocent end users at great risk. Understandably, even master installation electricians could be excused for missing the small print on instruction leaflets and assume that a certified Ex d (flameproof) cable gland could simply be fitted to a flameproof enclosure.
“It’s a natural conclusion to make,” Kruger points out. In the case of at least one well-known brand, the gland is also unable to comply with IEC torque requirements. It’s therefore been certified with yet another special condition. In this instance, the gland must be installed with a special proprietary spanner that emulates a semi-open ring spanner, and thereby prevents collapse of the compression nut. Of course, the installation would require such a spanner for every size gland and, even worse, if it is inspected routinely as required by law, routine maintenance tightening would also require a special spanner.
From a risk-analysis viewpoint, one must ask: Will such a gland ever realistically be installed with both an external clamp, and using a special spanner? Will it also five years down the line still be inspected and tightened with such a special spanner? If the answer is ‘no’, the engineer in charge and the installer are at legal risk, and the workforce in the plant is at mortal risk. Pratley’s new, fully-certified Ex d/e corrosion-resistant Enviro Compression Gland solves all of this. “It has zero special conditions of use attendant to its installation, and that’s a world-first,” highlights Kruger.
Pratley is well-known in the market for producing world-class electrical termination products. In fact, it takes product performance so seriously its policy statement reads that the performance of its products should outperform all others on the world market. It’s even signed by CEO Kim Pratley and displayed on the product packaging. Pratley claims that there’s almost no place on earth where its new cable gland cannot be installed. From Group I locations in underground fiery mines, and Ex d flameproof environments, through to the coldest and hottest climates on the planet, the gland has been certified for temperatures from minus 20°C to 95°C. It’s also IP66/68 certified and can withstand an incredible continuous depth of 350 m underwater. That’s equivalent to the depth of the North Sea 50 km offshore.
It’s made from high-tensile brass components encapsulated in a tough engineering plastic, which means it will not crack when tightening. This, combined with Pratley’s unique Taper-Tech® internal seal design, ensures safe installation in corrosive environments, without damaging the cable or compromising seal longevity due to cable cold-flow. The cable gland is suitable for installation in equipment Groups I, II, and III, and Zones 1, 2, 20, 21, and 22 hazardous locations. It’s also completely oil- and grease-resistant.
“I am confident that we have produced a product that not only complies with our policy statement, but exceeds it. Our aim was to produce a cable gland for hazardous locations that stands out from the rest and does what a cable gland is supposed to do, without compromising on safety. There shouldn’t be any limitations, special conditions, or ancillary tools. If you need it in metric thread, NPT thread, or stainless steel, no problem, as we can do that, too,” concludes Eldon.
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