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Originally Posted by
bec51392
Applying a solidly grounded wire immediately after performing a high-potential test:
Your Answer: Will ensure immediate personally safety.
Correct Answer: May damage the insulation under test.
I cant find anything that supports this. Everything I read says ground it after....
You guys have already found the standards but I'll just add, I've seen nasty cable discharges back in the old days of DC hipoting. Terminations can easily be damaged if you don't give it some time (4x test period was the rule of thumb) or use a discharge stick. Some guys just attached a rubber bungie cord to a ground, they have about 8 ohms resistance.
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Originally Posted by
SecondGen
You guys have already found the standards but I'll just add, I've seen nasty cable discharges back in the old days of DC hipoting. Terminations can easily be damaged if you don't give it some time (4x test period was the rule of thumb) or use a discharge stick. Some guys just attached a rubber bungie cord to a ground, they have about 8 ohms resistance.
After discharging with a homemade ground stick, I would apply electric fence wire to the terminals and ground and leave for the electricians to remove. I've seen cables (~2000ft long or more) build a charge after 24 hrs grounded.
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Originally Posted by
Kalbi_Rob
After discharging with a homemade ground stick, I would apply electric fence wire to the terminals and ground and leave for the electricians to remove. I've seen cables (~2000ft long or more) build a charge after 24 hrs grounded.
Another great point, can also confirm long cable runs will rebuild a charge. I've even seen this happen on low voltage cable too but not as severe as MV. It's a good idea to leave cables grounded with some bare wire for the next guy, if possible.
When you don't have wire, you can even just lay the exposed conductor against the equipment enclosure or ground bus, anything helps. Nobody wants to be responsible for having someone get bit.
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Originally Posted by
epenland
Applying a solidly grounded wire immediately after performing a high-potential test:
it cause damage to the cable you just test
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