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Featured Video - PMA UK - 22nd December 2014

PMA Highest Standards of Conduit Testing

PMA Highest Standards of conduit testing

As industry leaders in the innovation and development of polyamide cable protection systems, our products are certified for a number of demanding applications, including resistance to temperature, weathering, UV radiation and chemical agents.

But how do we know which product is best suited to which application? Where reliability is crucial, such as with large engineering projects, signalling equipment and offshore wind turbines, how can we be sure that our systems will perform months, even years after installation?

We put our products through their paces, thatís how!

Youíll be surprised to learn that the well-known International standards to which we must comply are, in comparison to PMAís own in-house tests, fairly relaxed. The IEC/EN standard requires only a minimal flexibility and doesnít consider fatigue at all.

There are two major general standards for cable protection products: European cable protection standard IEC 61386 and the UL recognition standard UL1696.

IEC 61386 has a matrix system of classification for each test and the product is classified in one of seven levels.

UL1696 (Standard for UL recognition) is much less flexible; for each test parameter just one level of performance is set and the result is either pass or fail.

These tests do not require each product to be tested to destruction Ė if the highest performance level is reached, the test stops, and you have no idea of what the product is actually capable. Thatís why our technicians insist on performing our own procedures to the point of destruction.

Take our Resistance to Bending test: IEC 61386 requires a flexible conduit to resist 5000 cycles (which isnít a huge exertion for a highly dynamic application in robotics, for example). The PMA test procedure DO 9.21-4420 records the number of cycles until the productís protective qualities are compromised. For the PA12 products PIS, PUE and XR90, values up to 4 million cycles are achieved.

PMA operates a number of different testing procedures, including:

  • Reverse swinging bending test
  • Reverse bending test
  • Third reversed bending test
  • Cold bending test
  • Self-extinguishing test
  • Impact test
  • Peak load test
  • Thermal ageing test
  • System pull-out strength

We aim to quote a 25% margin to the lowest test value for each of the above. If the values vary significantly after repeat testing, we build in more margin into the data sheet value - and if there is little variation in the results, we add less margin below the lowest value because we can be confident the quoted value will always be met.

And in case you wondered if we only used the brand-new, shiny conduit for our tests Ė we donít. PMA tests all materials with respect to their ageing characteristics using suitable fast ageing procedures such as heat exposure, accelerated weathering tests and natural outdoor weathering.

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