I don't know why this hasn't come up before, but here I am. I need a cable tracer that will tell me which breaker powers a particular set of wires so that I can safely open up a junction box and add a Quad outlet to it.

Back in the last century when I was buying my equipment, I noticed that cable tracing equipment generally had a warning against connection to live electrical power circuits, but that's exactly what I need to do.

Spending all of two minutes on a google search yields many cable tracers, but I don't see any touting their ability to trace a live electrical power cable. I figure if any of you have such an item, you can save me quite some time reading specs of one product after another, and if so, I thank you in advance!