I have a GB Instruments Circuit Tracker GET-1200 that I have had for a few years. I've only used it a couple of times, and then in a single phase panel. Today I needed to trace some receps/circuits so I got the Circuit Tracker out to try and find them. The panel that the circuits are in is a 3pf 208/120V. This tracker has a visible scale (green-red) and an audible alarm when you find the right breaker. The problem I was having was I got full scale readings on several breakers, which was useless to me. You could hear what sounded like a 60HZ hum or buzz on most every breaker. The audible alarm is a chirping sound, which I could hear in more than one place. I would hold it in one place for several seconds thinking that was the strongest signal only to find if you checked again, it had moved. I just gave up on trying with this thing. I couldn't flip the breakers because the receps. were being used. The only thing I can think of is there were apparently some MWBC in there and several non linear loads on some circuits, thus giving me a lot of trash and false readings. Any thoughts on this?