Any electricians?

[Don Hines]

I am trying to up grade an outlet with a GFCI. In order to keep from getting an "open neutral" reading on my tester, It obvious I am going to reroute some of the wiring. Do real electricians use jumper wires to find out where wires go to and what they feed? I do have enough sense to turn the breakers off before I make that connection. I have two breakers feeding this junction to control a bath, a hall light, and one bedroom.
Don