Wire tracer issues

Question

When we remodeled our basement, we wanted to move a switch that controls 4 lights. Here is what I think happened: The electrician spliced in a single piece of romex, so that the black wire runs to the new switch location, and the white wire runs back and connects to the other end of the cut black wire.

The wires are not marked, but it seems unusual to see a SP switch with one white wire and one black wire, coming from the same piece of romex?

I attached a tracer/tone generator, one lead to each wire - nothing. I attached the red lead to the "white" wire, and the black lead to the ground - nothing. I then attached the red lead to the "black wire," and the black lead to the ground - nothing.

Thoughts?

Answer 1

It's not unusual at all, it's just a switch loop

When using off-the-shelf cables, if you're in a situation where you don't need neutral but do need another hot, it is perfectly legitimate to re-task a white wire for that purpose. That is allowed in cables.

However it violates Code in 2 ways.

First, when a white wire is re-tasked to be a hot, it must be marked at both ends to indicate it has been reused as a hot wire.

Second, when a switch loop installed post-NEC 2011 adoption, a 3-wire+ground cable must be used so neutral can actually be brought to the switch location.

The practice of using a /2 cable and not marking white is a throwback to the 1990s.