Necessary to fix partially cut wire?
While putting in a dryer vent I partially cut one of the wires in the line that supplies dryer. I cut the black insulated copper wire about 1/3 of the way through. The uninsulated ground and the white insulated wire are fine. I wrapped the black wire with electriacal tape and then wrapped the entire wire group (surrounded by orange insulation) but was told I should cut out the damaged section and splice the ends together in a junction box. Is this necessary? Is there an easier way to do this, like maybe with some type of butt splicers? Thanks.