17 Aug Choosing Your Cable All Dielectric Vs Armored
All-dielectric or armored cable? With its added protection, built in conductor for locates, and ability to monitor for cable deterioration, the argument for choosing armored cable is a compelling one. But when faced with tight budgetary constraints, choosing all-dielectric cable might seem like the only option. The difference in cost, however, is not as big as you might think. “When you start comparing the cost between installing all-dielectric cable that has to be accompanied with a tracewire vs installing just armored cable, you end up spending around the same amount, or maybe even more with all-dielectric,” says Norscan Field Engineer, Wally Motuz. “Buying the cable that has a built in electrical conductor is a more prudent economical choice.”
There are scenarios, however, where all-dielectric cable is the way to go. In environments where there is poor soil connectivity, such as sandy, rocky, or soft terrain, all-dielectric cable could be preferable to avoid transient lightning strikes. “What tends to happen with a conductive armored cable is that the transient will see the cable as the better ground path, which could ultimately damage the cable,” says Motuz.
No matter what your reason is for choosing all-dielectric, it’s imperative to install your tracewire inside the protective conduit to avoid headaches down the road. Recently, Norscan was tasked with the job of replacing a faulted fiber cable for one of our clients. The root cause of the ground fault, which occurred on their tracewire, dates back to when the cable was originally installed. “They had a ground fault on the tracewire,” says Motuz. “Initial installation of that tracewire was outside the conduit, and the damage was done as the conduit and tracewire were being installed. Over time, the initial installation fault deteriorated to the point where the cable had to be replaced (hard ground fault condition).”
It’s problems like these that we see time and time again – and they are totally avoidable. Whether it’s all-dielectric or armored cable, sound installation practices are just as important as the cable you choose.