Amprobe ST-102B Socket Tester with GFCI, Red

This circuit breaker tracer works perfectly but you MUST follow the instructions. The unique auto-calibration system ensures that the correct breaker is identified every time without any false indications.Most devices like this suffer from problems with "false positives", meaning they beep at more than one circuit breaker and it's difficult to tell which one is actually powering the circuit you are working on. These false positives occur because the transmitter signal can be induced into other wires if they run parallel to the circuit under test. This occurs frequently in homes and businesses because all the wires must eventually go back to the breaker panel and many follow the same path to get there.This device uses a 2-step identification process to eliminate those false positives. When powered up, the device starts out at a high sensitivity level, meaning it will detect the transmitter signal even if it's weak from a far-away transmitter or caused by an "induced" signal. After the transmitter is plugged into the powered outlet, you slowly scan ALL the circuit breakers with the device to set the calibration level, disregarding any beeps. Each time the device detects a signal and beeps, it resets it's sensitivity threshold to match that signal. If it encounters another higher level signal it resets to that higher signal. In this way, by the time you are done scanning all the breakers the tester has set itself so that only the very highest signal in the circuit breaker box will activate it. This is what guarantees that when you make the second pass, only one circuit breaker, the one with the transmitter plugged in, is identified.I tested this in a breaker box where all the circuits were already identified. In every case the first pass through the box yielded several beeps, as circuits with induced signals were detected. But also in every case, the second pass through the box correctly identified the circuit under test, with no false positives.There is one drawback to this particular tester - the power switch is too sensitive and it takes a very light touch to turn it on. Just holding the device it's possible to turn it on accidentally and if it's left in a portable tool box it's likely to be turned on by jostling around. It will turn itself off after a delay, but it would be better if the on/off switch was not so sensitive.

I have both the Amprobe BT-250 and BT-120 circuit breaker tracers and use them all the time at work. They are physically identical and operate exactly the same. The main difference is that the BT-120 is rated for use on circuits up to 120V [50-60Hz] and the BT-250 is rated for circuits up to 250V [40 -70Hz]. The BT-120 includes the transmitter and the receiver with a 9V battery installed, but nothing else. It may be hard to tell from the product description, but the BT-250 actually comes as a kit that includes a nice foam padded hard case, test cord with alligator clips, light socket adapter and a 9V battery installed in the receiver. The transmitters on both models are powered by line-voltage from the circuit under test. Both tracers seem to work equally well at locating circuit breakers for me probably 99-percent of the time. There are some odd circumstances though where the receivers can’t locate a circuit breaker accurately. I’m not sure exactly why this happened, but for me at least, it is only a rare occurrence. Overall tough, I'm happy with how these perform and would definitely purchase again.

It's a pain when you open a breaker box and face 40 unlabelled breakers. This device plugs in the outlet and you pass the hand-held unit over the breakers and it will identify the one that controls the circuit in question. It works best if you touch it to the breaker right over the switch. Accuracy was 100%. It will also identify the circuit in a bundle. Just touch it to the ROMEX shielding of each line. However. the build quality is cheap. A sloppy "on-off-test" button has the thing beeping from the moment you pick it up. You must hold the button down to shut it off. So I probably wouldn't drop it in the bottom of my tool bag, either. Otherwise, the operation is flawless,

Works great. Here is what the instructions don't tell you. If you are testing multiple outlets you need to reset the receiver after testing each outlet. Let's say you test outlet #1 and using the tester you locate the breaker and turn it off. All is good and you identified the breaker associated with that outlet. You then move the transmitter to a new outlet. You need to push the button on the side of the "receiver" which looks like a remote control. Pushing the button resets the receiver (remote control looking device) After pushing the button you need to slowly scan the breakers. Scanning the breakers calibrates the device. It needs to be calibrated for each outlet. The receiver will light up and chirp at you. Do not hold the button on the receiver down. Push the button once and it will turn on the receiver. You will see the little red light turn on. After scanning the breakers to reset the receiver you slowly move the receiver over the breakers for the second time. It will locate the breaker for sure after you do this. I had my nine your old son scanning the breakers and I was in the basement on my cell phone with him moving the transmitter from outlet to out let. He was able to pick out the breaker 100% of the time. We scanned 9 different breakers.Works great! Read the instructions and my pointers and you will be happy with this tool.