Thanks for the help Scott.
My meter is auto-ranging, but I'll try metering the cord end as you suggested. If this is inconclusive then my chances of figuring out exactly what is happening with the lights are not good. This is my last week working with this company and my next few days will be busy with roughing in the offices and showing the new electrician what has happened so far on this job. I just won't have the time to go get the megger and do a thorough investigation.
As far as the lights, they are 400W M.H., pulse start or not I don't know.
A large part of the problem is probably the cables feeding these lights. They look like they have seen better days. The lights are temporary for construction and have been used many times...and so have the NMD cables powering the lights. Maybe I'll run an extension cord up to the lights and see if the GFCI trips then.
I explained what was happening to the new guy and may just have to leave it at that if I can't make the time to check this out some more.
Thanks again!
Shawn.
