Discolored Wires

Did you measure if current flows through your ground wire? It is also not exceptional that wires discolor. Some batches might be out of specs. That is what I understand with discoloration.

If they all turn out brown, on the way to burned....

Than there is really a problem. Maybe first check if everything is wired correctly. And megger the circuit out, contactors included, and also the ground bus on the contactor. Feedback appreciated.

The 20-amp breakers may be oversized for the actual loads. Though 8 amps may not overload or trip the CBs, it may be overloading some individual conductors. If memory serves, the internal wiring in fluorescent fixtures is about 18-gauge, which is good for about 6 amps. Thus 8 amps may be overheating some wires. You might want to consider supplementary protection for the individual fixtures. This is all a bit of a guess; I don't do very much lighting.

If this is the case, it should be checked out first. I just wonder here how the fixtures can pass a test or the set up lacks installation regulations (if they do not restrict the number of armatures to be connected through using partly the same wires).

But the case has to be solved.

If the discoloration is very local, close to the connector points, and the wire is of appropriate size, maybe the screws are not tightened enough?

Is it the copper that discolors, or the insulation of the wires or both? And what about the screws and seats? If a heat scanner is available, it should show where temperatures are too high.

If the wiring is undersized, I should expect discoloration on more spots. I also don't exclude the contactor, where depending on the type, maybe a bad contact heats up one output. Although the ground connector should not be switched. Maybe as a test, you could connect through a CFGI 1. Before 2. Behind the contactor. Ground faults will show up this way. The ground wire involved looks strange to me too. Am I missing something? Thanks Tornado.

no current on ground wires.

No more than 8.5 amps on any light circuit.

Connections all tight

N wires are OK

Discoloured wires near the breaker (or any connection) implies a high resistance connection creating local heating.

Given the other symptoms that you described, a voltage drop may be contributing to the other symptoms.

A QUALIFIED electrician could easily check this by measuring voltage drop in the live circuit. Remember SAFETY is the important issue here. They may also be able to check and confirm correct wiring during the same visit.

Consult a qualified electrician locally, ideally before a fire results in damage, destruction and loss of life.

it could be a ballast with a very poor power factor leaking a lot of harmonics back onto the line that is causing the wires to heat up too. try to determine if the wires are heating up, preferably using a non-contact IR thermometer. if they are not heating up, then it could be oxidation due to ozone or a reaction to the UV leakage of the fluorescent tube.

Local EC asked for help.

Did the IR all ok.

Discoloring is in an enclosure with the operating contactorsThe lights are T8 3 bulb 4 foot troughers. Voltage is 120v with ballasts rated 120 to 277v

Wire is green, red, blue, which should eliminate the bad copper theory.

Monitoring overnight for volts amps, harmonics, PF, freg.,etc.

Primary concern is failures of bulbs and ballasts in afast food resturant kitchen only open for 4 -5 months.

Could it be environmental? Grease vapor from the deep fryer maybe? plastics (pvc) could absorb grease and discolor.

The copper is discoloring not the insu;ation as I have said 4 times before.

I'm very sorry Joe, sometimes I can be pretty thick, I didn't pick up on the fact you were talking about the copper not the jacket before. Mea culpa! (I've gone back and re-read and still didn't see where you made it clear you were talking about the copper not the jacket, but like I said I can be pretty thick at times too.) But even then it could still be environmental, high humidity and/or corrosive vapors in the air (cleaning products such as ammonia based glass cleaner or chlorine based bleach are pretty bad about turning copper dark. it can embrittle it too.). you might just have a cleaning crew that is being too dang good at their jobs! animal fats can be pretty dang corrosive too.