5kv PT Cabling

[upstater49]

We need to connect some PT's to 5KV bus. The PT's are fused at 2 amps. This wiring will be in one enclosure. What kind and size of wire is needed? Do stress cones have to be utilized? Thank you for any help.
Rocky

 

[wirenut1980]

Re: 5kv PT Cabling

I assume by PT you mean potential transformer, and I assume you are talking about the 5 kV side wiring. If that is the case, see NEC Tables 310.67 through 310.86 depending on your particular situation. I would recommend EPR or XLP 5kV minimum insulation rating. Use the tables for temperature rating based on what you will want. Not sure about stress cones are needed?

 

[lile001]

Re: 5kv PT Cabling

We recently put a potential transformer on a 5KV motor starter, and bought a length of high voltage insulated cable from the same source as the transformer. It was just extra heavy insulate cable, not shielded and no stress cones.

CT's are an interesting case. A current transformer, I am told, will measure current THROUGH THE SHIELD. And I have proved this does work. I was skeptical at first.

Make sure everything is grounded really well, like your PT and the steel case that you have around your PT, if you don't want to become a fluorescent light bulb.

 

[kiloamp7]

Re: 5kv PT Cabling

Generally,primary wiring for PT's (VT's) on a 5KV application is done with non-shielded wiring rated 5KV minimum. Type GTO wire is available in 5 & 15 KV ratings. Other types of wire (I prefer EPR) are available that are fine also. Wire size is not real important here & you are somewhat limited anyway in availability of wire for this purpose.

No - no stress cones & no shielding is required, & is very possibly not desired.