In the Nick of Time. Damaged Electrical Conductors.
Submitted by DonHester on Sat, 10/10/2015 - 11:10.
In the Nick of Time. Damaged Electrical Conductors.
Wenatchee Home Inspections
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.
In this example with stranded aluminum wire, the tool cut deeply into the outer ring of wires, decreasing the total diameter of wire and reducing the strength of the wire. In time (anywhere from days to years) normal vibrations throughout the home can cause the wire to break at the nick. If the space between the broken ends is small enough arcing will occur across the broken conductor as current tries to flow to the electrical load. The arcing will continue to build up excessive heat which again is not detected by the fuse or circuit breaker, and fire can result. (A good reason for AFCI protection. A nicked wire, if left uncorrected, will most likely trip an AFCI).
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.
“Codes are minimum standards and most houses are built by the lowest bidder”
Don Hester
NCW Home Inspections, LLC is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…
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