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that plastic clips will melt and give way in the event of a fire far more quickly than metal clips , resulting in the release of electrical cables which are then exposed to contact .
Back in 2005 after firefighters tackled a blaze in Stevenage an investigation found that one of them had cable insulation stuck on the palm of his glove , indicating he had attempted to untangle himself from electrical cabling that had fallen as a result of the plastic cable ties in the building melting .
Regardless of the type of project being worked on , installers are advised to seek products which meet high standards of fire resistance , particularly for escape routes and areas that may be at risk of fire . It ’ s also important to look at how the fixing is
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It is important to consider the type of wear and corrosion resistance that every individual application requires before specifying plastic or metal . |
embedded into the building structure as you may need to use metal products for more than just the cable tie , for example within cable mounts and other supporting fixings . There is no point installing a metal cable tie or clip if the wall plug connected to it is comprised of plastic , as the plug could still collapse and put lives at risk .
Adhering to modern methods of construction
With the rapid pace at which new buildings are being constructed as modern methods of construction such as modular continue to grow in popularity , electrical engineers and installers are finding the time they are allowed on site decreasing . As a result , there is a growing demand for cable tie applications and fixings that are quicker and more convenient to install .
For many electricians , the plastic P clip is the default application for permanent or semi-permanent cable fixings . Whilst this product is ideally suited to floorboards , and applications where there is no risk of ceiling collapse in the event of fire , they do not comply with BS7671 standards . Of course , their comparatively lower cost makes them popular and the secure fastening they provide is making a huge difference to the electrical installation industry . However , for certain applications , such as escape routes , they can take longer to install than metal alternatives . With both metal and plastic P clips , an electrical installer needs to feed the cable in through the P part of the clip before nailing it through with a hammer . When installing a metal cable clip however , installation time is reduced since you only have to position the clip and nail it through – there is no need to manually thread it through the P . This may not seem like much of a time saving , but if you multiply this by the number of times you would typically install the product on an average job , it can add up to make a big difference for project lead times .
Resisting the urge to continue bad habits
It is also important to consider the type of wear and corrosion resistance that every individual application requires before specifying plastic or metal . For example , some plastic ties and clips are unsuited to applications requiring high structural strength , such as heavy equipment components and certain building materials . It also has a low resistance threshold for corrosive elements when compared with
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metal . For areas where moisture is a concern , such as near to windows or doors , metal cable clips or fasteners are more suitable , as they are a lot more resistant to water , extreme temperatures , and even dirt ingress .
HellermannTyton ’ s metal nail clip was originally designed for the telecoms sector . As a result , there was a real demand for the clip to be fire resistant , whilst also offering ease of installation . Upon identifying the opportunity to use this product for escape route cabling following the introduction of BS7671 , it rapidly became a valuable addition to HellermannTyton ’ s extensive range of metal fixing products , with particular interest coming from the retail industry .
Of course , plastic cable clips are still important and have a vital role to play in the majority of projects that an electrical installer will carry out day-to-day , but whilst they play a crucial role in building infrastructure , they are no longer suitable for escape routes . Yet many installers still use plastic cable clips in this context because BS7671 of the Wiring Regulations only cites public buildings as an area where plastic is no longer suitable .
With the electrical market growing as manufacturers of cable management products engineer products that are easier to install , professionals are increasingly trading on their reputation . As metal is now considered best practice in public buildings , the same approach should be applied to any project where escape routes require cabling . After all , any structure carries a risk of fire and it is the electrician ’ s responsibility to minimise this risk as much as possible . Plastic may be the cheaper , more convenient , and commonplace solution , but for certain applications it will not always be the most effective . To improve standards of the electrical engineering industry , regulations such as BS7671 need to be understood and carried out , with best practice applying to all types of building . Only by respecting these regulations and understanding the importance of using high quality and approved products for every application , can the sector confidently state that it is always helping to make buildings as safe as they can possibly be .
The BS7671 regulations will possibly be widened to not only include escape routes but all wiring in the future .
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July 2017 | 43 |