A wire has been installed without proper strain relief The 1

A wire has been installed without proper strain relief. The 12-gauge, insulated, solid copper, electrical wire has been supporting a direct tensile load of about 100 pounds for several weeks. Strain relief has been added to remove the load. The wire needs to be evaluated for possible replacement. Should you replace the wire?

Solution

12 gauge solid copper wire has cross sectional area of 0.00512 sq.in. Under the 100 pound load the tensile stress is 19531 psi. Though the yield stress for copper is 30,000 psi, the same is around 20,000 psi with 0.5% extension which may be reasonably assumed as the wire was under the load for several weeks. The wire may be close to breaking anytime. Hence it is advisible to replace the wire.