Spiking HV and LV cables
Spiking HV and LV cables
(OP)
Hi everyone,
I'm a mechanically trained engineer but im currently training to be an electrical Authorised Person for HV and LV systems. Im looking at cable spiking at the moment. What kind of ohmic values would I be looking for before and after a cable is spiked on both LV and HV??? And also would these vary depending on the earthing system i.e TNS, TT, TNCS???
Some advice and info wold be great thanks.
Ben
I'm a mechanically trained engineer but im currently training to be an electrical Authorised Person for HV and LV systems. Im looking at cable spiking at the moment. What kind of ohmic values would I be looking for before and after a cable is spiked on both LV and HV??? And also would these vary depending on the earthing system i.e TNS, TT, TNCS???
Some advice and info wold be great thanks.
Ben






RE: Spiking HV and LV cables
RE: Spiking HV and LV cables
Back when I was in the locating/repair business (working alongside line crews), spiking was used more as a safety measure to ensure the cable to be worked on was de-energized. The termination ends could usually be identified by switching/parking the cable under repair, verifying that its ends were de-energized and finally grounding them. At this point, it becomes necessary to identify which cable or phase is the one of interest in a hole in the ground. We would do this by various techniques. Non contact voltage sensors were of some use, although a bunch of nearby live runs can couple a signal into the dead cable. Injecting a locating signal into one end of a run was pretty reliable. Finally, when we were relatively certain we had the correct phase, the crew would spike it with a temporary ground. On the few occasions we had mis-identified the cable, a fuse at the source end would blow.
RE: Spiking HV and LV cables
The system I am working on will be 11 KV delta config on a TNS system if that helps?
Thanks again.
Ben