Choosing the right electrical products for the right conditions
In places subject to extreme conditions, the right product choice is essential. We get the lowdown from two suppliers who are adept at understanding the conditions.
Quality Director, Prysmian Group
General Manager, CBI-Electric Australia
|How much of an effect do extreme weather conditions have on product performance and use?
The impact of extreme weather on cable performance is huge. Extreme weather can damage the cable completely (wind, hail) or cause potential long-term degradation, which is even more dangerous (water ingress, high temperature) for the end user.
It can have a significant effect depending on where the product is installed. If you had a thermal breaker in an outdoor enclosure, you’d have to derate it, and if it was in full exposure to the sun and got up to 60°C and beyond inside the cabinet, there’s a good chance it could start nuisance tripping.
|What are some examples of this in relation to the products you produce?
Heat can make a TPS cable degrade faster, especially when installed between insulation boards in a roof area. We have created a new recipe of PVC to make the product more stable in order to suit this kind of application. Called non-migratory TPS cable, it can be installed between the insulation boards, will not cause any leakage of the plasticiser and keep the circuit safe.
The vast majority of MCBs and RCBOs are thermal magnetic, which means they are affected by ambient temperatures due to the operating principle being reliant on a bi-metal strip. Our QF and SFM range of products use hydraulic magnetic technology, meaning the trip point is not affected by ambient temperatures and always carry 100% of the rated load.
|What testing do you do to ensure products are capable of withstanding those extreme conditions?
Thermal analysis, such as an ageing test, is critical for high-temperature endurance. Besides the standard testing, we also design and customise the testing to simulate the application condition. We have designed the test to evaluate the PVC plasticiser migration to the insulation board with certain conditions to make sure that our non-migratory TPS cable is suitable.
|We have our own NATA equivalent approved test lab at our head office in South Africa and also use third-party labs like TÜV to conduct tests to Australian standards. The ranges that use hydraulic magnetic technology are tested to operate at the 85°C and are also extensively tested for humidity, shock and vibration.
|How should contractors assess what products are required when working in areas prone to extreme weather?
It depends on the application condition. For example, if you need protection from impact, water ingress or extreme temperatures, the installation condition can restrict the product selection. Contractors need to find the right product for each application as a starting point.
They should first check the operating temperature of a RCBO or MCB. When a cabinet is going to be exposed to the sun (not under an eve, awning or having double skin) you’re going to have ambient temperature that increases the internal temperature of the cabinet, so you need a product that’s going to last and typically be unaffected by ambient temperature.
|What are the risks of using a product that’s not capable of withstanding those conditions?
|Not using cabling designed for the conditions can cause a potential electrical failure, which is highly likely to be a starting point of a fire incident.
Nuisance tripping, downtime and call out fees to remote sites. The conditions we are discussing here are not too common on a day to day install and we use our own thermal magnetic range. However, when faced with known extreme conditions we will always recommend the Hydraulic Magnetic based on the product’s ability to withstand extreme heat and cold.