Megging 480-volt power cables


Thread Starter


Hi Guys,

I'm going over to Meg some 480-volt feeder cables for a small commercial facility. I thought I would I would beef up the report by quoting 2005 NETA standard. I was amazed to find the lower limit is 100 megohm at 1000 volt.

I come from an industrial paper mill where any 480-volt cable was “good to go” above 2 meg.

I realize that the rest of the world does not operate like a paper mill, but do you guys recommend a customer pull new cable in a commercial facility or even a public assembly building if a 480-volt feeder cable megs 30 megohm?

Seems like overkill but I wish to conform to the current “standard of care”.

Plus more work for the electricians.

Does the insurance industry have a post water intrusion lower resistance limit that they are willing to pay for cable replacement?