LV Cable HiPot
LV Cable HiPot
(OP)
I have used meggering for 1 minute as stated in NETA for field cable installations below 1kV. However Southwire in their website identifies hipot test for LV cables and one of our cleints wants to have all LV cable above 250 kcMil hipotted. Can you explain were is Southwire geeting these values and are they really valid. for example for cables between 550 and 1000 they recommend Hipot at 9.6kV DC for 5 minutes.
thread238-130438
thread238-130438






RE: LV Cable HiPot
I have been very involved in NETA for many years and cable testing has been the hot topic for the last 2 years or so, LV cables never came into any discussion.
Why dont you ask southwire where they get this spec from? If you find out, please post.
RE: LV Cable HiPot
RE: LV Cable HiPot
RE: LV Cable HiPot
Since LV cables are not shielded, a withstand test is next to useless because the voltage stress distribution across the cable insulation is not equal along the length of the cable. However, if there is a ground plan near a part of cable insulation, that part will be stressed. If there happens to be a crack in the insulation being stressed, some leakage may be recorded by a sensitive micro ammeter. Go ahead and megger, hipot, all you want, but understand the risk that you can have a failure literally one minute after reenergization with out warning. One minute should be more than sufficient to detect leakage current issues.
Benjamin Lanz
Vice Chair of IEEE 400
Sr. Application Engineer
IMCORP- Power Cable Reliability Consultants
RE: LV Cable HiPot
It is a problem as if we have a project with Southwire LV cables a customer might refer to this type of test as " recommended by manufacturer" type test!!.