I am doing some wiring and am wondering about a few basic things.
I notice that on a couple of wires after I had them pulled though the box
and clamped down, the clear sheathing on the THNN wire, (romex as well as
solid conductor) was roughed up or nicked or in a one case delaminating
where the wire bends. I assume that this is OK. I assume that all I have
to worry about is not damaging the insulation inself on the conductor? What
is the purpose of this clear sheathing on the surface anyway?
Secondly, after I had some new boxes wired up, I measured the wire and found
it to be about 7 1/2" from the front of the box. I know the recommendation
is 8" but I have measured many boxes in the house and am hard pressed to
find one with 8" of wire past the box. What is the normal length
electricians usually leave past the front of the mudring?
Thirdly. I am running some Romex in the kitchen as whips under and over
cabinets. In some locations the romex will be exposed before it enters
surface mounted boxes. Is this a problem at all?