In the Nick of Time. Damaged Electrical Conductors.

It not all that uncommon during an electrical installation that a wire gets nicked during the stripping of the insulation. As a home inspector I try to evaluate the wires at their terminations to see if any notable damage has happened.

If you nick a conductor, that tiny notch forms a point of stress concentration and potential for failure. If the wire nick is severe enough, one of two things may happen; The nicked conductor is now no longer capable of carrying its rated amount of current through the damaged portion. If the nick damage is deep enough, the wire will start to overheat at the nicked area. This overheating most likely will not be detected by the fuse or circuit breaker and the end result could be an electrical fire. This is much like having an undersized conductor for the rated breaker.

Nicked (or stretched) conductors reduce the conductors diameter in a localized area. Depending on the actual damage it may not cause heating at the location under normal load conditions however the mechanical strength of the conductor has still been compromised and flexing near this area could weaken it to a point where the conductor could fracture and fail.

Electrical installation need to be performed professionally and with care. Mistakes such as this can lead to fire and shock.  If a wire does accidentally get nicked, the proper plan of action is to cut the damaged part off the wire off and try again.