My freind just recently started a business and rents an 18,000 square foot warehouse. Off the top of my head, there are about a dozen lighting circuits. The breakers should really all be replaced, and there are signs of overload in the wires(insulation falling off inside the load centers)A few of the breakers keep tripping, so I replaced them with new ones. He keeps calling me to change the breakers. As of right now, I still have a year left before I can take my journeyman's license. What would you do?

if insulation is falling off the wires it's almost certainley time for a re-wire. In my opinion.

I agree with last poster that it is time to rewire, but it sound like you have marginal circuit sizing and under size wire. I suggest you increase the number of circuits and increase the wire size for voltage drop.

This sames like are there just too many lights on a circuit. While circuit is not overloaded the it probably is pushing the 80% load. You need to get the load down so you are pulling no more than 80% including the 125% for continuous duty.

Have you put an amprobe on the wiring to see what it is you're dealing with?

How old is this installation? What kind of fixtures are they? What kind of wire is it?

[This message has been edited by stevecheyenne (edited 02-12-2007).]

If the breakers are being used to control the lights, you should make sure that they are HID rated (it will be marked on the breaker, you usually have to special order these).