Cables 100 or 133% insulation
Cables 100 or 133% insulation
(OP)
Hello all,
I would like to know if:
There is any normativity to use cable insulation in electrical systems of 460, 480 V. (low voltage)
The neutral system currently is solidly grounded and there are plans to install a neutral resistance to limit single phase to ground faults currents, however, as temporary overvoltages may happen, we do not know if there are some code requirements to use some insulation of 100 or 133%.
As far as I have read on NEC, 133 and 173 % insulation level only is applicable to medium voltage cables.
Any help or comments will be welcome!
I would like to know if:
There is any normativity to use cable insulation in electrical systems of 460, 480 V. (low voltage)
The neutral system currently is solidly grounded and there are plans to install a neutral resistance to limit single phase to ground faults currents, however, as temporary overvoltages may happen, we do not know if there are some code requirements to use some insulation of 100 or 133%.
As far as I have read on NEC, 133 and 173 % insulation level only is applicable to medium voltage cables.
Any help or comments will be welcome!






RE: Cables 100 or 133% insulation
Yes, 100%/133% is typically for MV systems.
Rafiq Bulsara
http://www.srengineersct.com
RE: Cables 100 or 133% insulation
http://www.justminisplit.com
RE: Cables 100 or 133% insulation
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Cables 100 or 133% insulation
As it was said before, cables in North America are rated for 600V (1000V is usually used in Canada as the rated voltage is 600V). Therefore, there is no issue using 600V cables for 480V system.
What you have to make sure that you have ground fault indication as this is a code requirement.
For more info on high resistance grounding you can check out www.i-gard.com.
Regards,
Zsolt