Accessories

Waste of a Good Battery
The greatest utility I ever received from this tool was watching the shower of yellow plastic after I threw it into the concrete floor. I've actually made more trips to the circuit box by using this tool than by random guessing. It does not work.

A.W. Sperry CS500A Circuit Breaker Finder
I'm a home owner and I found it to be an easy way to find the maximum electrical load distribution on my breaker panel. With it's help, I was able to add more load to the circuit without guessing.

Gain to be used based on purpose
I have used this to trace the path of the wires through the wall, so high gain was important. When tracing into a breaker panel, the gain should be minimized. Also, you can adjust where on the breaker switch you position it to ensure it is picking where the wire comes in. Some cross talk is possible, but with care, should not be a problem.
Only downside is that you cannot use it with a depowered outlet. It would be great if both parts had a battery, so you could trace dead outlets to the source (breaker, switch, GFCI) the way a phone-line tone and probe works.
To use with light sockets, just get one of those $1 screw in outlet devices at any hardware story.

Breaker Finder
Excellent, found the breaker the first time, MUST kep the gain down as far as possible or else it will read feed off all breakers in the box.

No problems
I read some reviews of this product and noted the problems some users had. I too saw the unit beeping at any part of the breaker box, but after adjusting the sensitivity dial, the beeping only occurred over the correct breaker switch. One user suggested switching off a breaker until the beeping stopped, which would indicate the proper switch, in cases where the unit couldn't indicate the exact switch. This suggestion was a good one! It is helpful to read the instuction booklet before using the device too!