I bought this indicator to help me deal with some phone lines running in front of my house behind some building materials. First I tried connecting the red wire to one wire and the black wire to the other wire of the pair. I seem to have received only a modest signal from the tracer. However, I noticed that both pages 1 and 2 of the manual mentioned that the black wire should go to ground and the red wire should go to wire. This was especially true when a strain was present on the line or a spike versus a ring was identified. I only used the grounding method to trace my line that wasn't complete. Connecting black to ground resulted in a very positive signal pickup along the length of the cable, about 80 feet away. It was through wood and plaster. It was possible to identify a specific cable among several other cables. The ground I used was just a ground wire to my electrical box (open in my garage). This should work the same way with an outlet ground, with a few precautions to make sure it's properly grounded. the toner wires were simply connected by a pair of wires. I did not find that with this device. But with the black wire connected to ground and the red wire connected to the traced conductor, the tracer in this set performed very satisfactorily. It seems to me that the manufacturer should emphasize this way of working unless I have a device that is malfunctioning. If you are having trouble getting good tracing results, I would recommend using it this way.