What is the proper term for when you are working on a circuit that has the breaker turned off and you still get shocked. Is that called backfeeding a circuit? I was trying to do a search for causes.

A friend of mine is working on some lighting. When he turned off the breaker the light went out but when he started working on the wire inside the box he got a shock. Is there a common cause for this? I'm sure this has come up in posts but I did not know what the proper term to search for. I have had this happen once on my house as well. Thanks

A couple of things can do this:
1) Another Circuit or switch leg on another circuit.
2) A multi Circuit(2 circuits on opposite phases sharing 1 neutral) Opening the Neutral that is shared with the second.
3) A Neutral on a different circuit That power is on and with a load, when you interrupt it knocks out the load, then that Open neutral will be live. If you touch this and at ground potential, you will get shocked.
4)?
Several circuits can go through one box.
The tester mentioned above works great for the fact, you can push it all up inside a box, to verify any other live wires, without removing wirenuts or a reference to ground.
Labman, I have a Tic Tracer, They work great. I don't recommend anyone to do this.
I have good rubber shoes, grab on to a live wire. That tester will now work when you place near a neutral or ground. The GB should do that also. It was a test, and don't need to do anymore.
Take Care

I''ll take your word for it.