ECN Forum Forums General Topics of the Trade General Discussion Area How hot can conductors get before Its a problem?

Last night while adding circuits to a 200a panel i found that someone had fed a second panel by terminating the feeders on the main lugs of the first panel.The feeders to the second panel are smaller and warm to the touch.I didn't have time find the distrobution breaker to check It's size.I asked around and was told that just because the wires are warm dosen't mean it's a problem.I'll have to check it with the IR gun tommorow.thanks