Review: Klein ET300 Digital Circuit Breaker Finder

Way back in January, I wrote about the Klein ET300 Digital Circuit Breaker Finder. It does exactly what you think it does – it helps you match an outlet to the controlling circuit breaker.

First, you plug the transmitter of the this handy $40 tool into an outlet that you want to deactivate. Then, you use the receiver to scan the service panel and it’ll tell you which breaker to turn off.

Stuart requested a test sample for me to review, and I received it last month. I delayed the review until I could try to resolve some of the issues I had while testing the ET300. When I ran into a wall, I was put in touch with a product manager at Klein.

Operation

The Klein Breaker Finder has two parts. The transmitter is the part you plug into an outlet. It sends a signal through the wiring over the whole circuit. This signal is picked up by the second part of the tool, the receiver, which is what you use to scan the breaker panel.

Incidentally, if you have a cord plugged into another outlet on the same circuit, the receiver will sometimes detect the signal in that cord. Since it only works sometimes, this is not a guaranteed way to determine whether one outlet is connected to another.

My first tests with the Klein circuit breaker finder didn’t exactly go predictably. For example, I was seeing false and multiple breaker identifications. There were several things I tried that improved the consistency and accuracy of my results, such as reversing the transmitter, scanning the panel in a different order, and scanning a different part of a breaker.

I was put in touch with Bruce Kuhn, Klein’s Test & Measurement Director of Product Development, who said that it shouldn’t matter which orientation you plug in the transmitter into an outlet. Either way you plug it in, it’ll draw current that the receiver will detect at the electrical panel as the signal.

The signal is actually present all over the panel because it propagates on the bus bar behind the breaker which the transmitter is plugged into, but it is strongest at the original breaker.

This is why you have to “train” the receiver. When you train the receiver over an electrical panel, it’s looking for the highest signal quality, but to do this it has to first recognize and eliminate the other weaker signals.

Think of it this way – you have to look at all of the lights in a room in order to find the brightest one.

Startup & Use

After I freed the ET300 from its blister pack, I didn’t need to install any batteries. The transmitter is powered directly from the outlet you plug it into, and the receiver ships with a 9V battery already installed. So I plugged the transmitter into a nearby outlet and brought the receiver over to my main service panel.

After powering up the receiver by clicking the button on the side, the unit chirps and the green arrow lights up momentarily. You can tell it is on because the red LED by the switch remains lit.

Then I passed the receiver over the panel once, to train it. The receiver chirped after passing over different breakers. When I passed it over the panel a second time, the receiver lit up and beeped only when it was directly over the correct breaker.

If you want to detect which circuit a particular light is on, you can pick up a socket plug from the hardware store for a few bucks. Turn off the light, remove the light bulb, screw in the socket plug, plug in the transmitter, and turn the light switch back on.

You use the receiver at the service panel just like if the transmitter was plugged into an outlet.

Remapping my Service Panel

To really test this device, I decided to remap my service panel.

Being the 3rd owner of the house, the panel was getting pretty confusing. I actually knew who Andy was and where he slept, but my kids don’t. Circuits have been added and expanded, all using adjectives that probably made sense to the person that wrote the labels, but whose meaning has been lost over the different sets of owners. It was time to start fresh.

Another good reason to wipe the slate clean was that I could do a partially blinded test of the breaker finder. I concede that this isn’t a fully blinded test, because I generally know which circuits go together, but I haven’t used the panel enough to remember which exact breaker controls our bedroom lights for example. So I would be depending on the breaker finder and not my own memory to find the correct breakers.

I removed the panel cover and with the help of a heat gun and some rubbing alcohol, I erased all traces of the old labeling system. And since my panel is so old that it doesn’t have the breakers numbered, I used my labeler to number them myself. I left the labels on the breakers because I didn’t want to monkey with the actual breakers on a live panel.

This isn’t my only breaker panel, I have two sub panels: one for an addition and one for the garage. The subpanel for the addition is in my shop, consequently it controls most of my shop . You also may see a few smiley faced stickers on the breakers, that was my first scheme I tried before the numbers, I just didn’t have enough colors.

I only used the breaker finder in outlets and light sockets (with the Edison base adapter), I did not attempt to use it in hardwired circuits like the furnace, where I would have had to probe the circuit with wire leads.

Although I ran into a few correctable issues that I’ll describe in the next section, the breaker finder worked pretty much like it should have. It even detected the correct breaker on a multi-branch circuit (two circuits using a common neutral), although it didn’t detect the complimentary breaker. A multi-branch circuit should be wired with a ganged breaker, but in our case it is wired to breakers 1 and 6.

This means you need to be careful, because even if you turned off the correct breaker there still could be power running through the outlet box. This is as good a place as any to say you should always test the wires in a box with a non-contact voltage tester, like Klein’s NCVT-3 Voltage Tester, before you work on it.

Another thing you should be aware of when you are using the Breaker Finder is if you have sub-panels and which breakers feed them. I was reminded of this when I was testing an outlet in the kitchen. I couldn’t figure out why the receiver was pointing to a 60A double gang breaker when I was expecting it to be on #13 or #14. Then it hit me it was tied into the addition. So I walked over to the addition sub panel and sure enough I found it on a breaker in there.

To see how far the signal would travel I plugged a 100′ extension cord into the outlet on a circuit in the garage and stretched the cord into my neighbors yard. I plugged the transmitter into the end of the extension cable. I had no problem finding the correct breaker on the sub panel in my garage. It even showed up on the breaker feeding the sub panel in the main panel.

Notice how I run the breaker finder with the label facing up on this panel as opposed to having the label sideways on the main breaker.

Not satisfied with just 100 feet, I plugged an 80 foot cord into the end of the 100 foot cord and the transmitter into the end of that. I again found the signal in both the garage panel and the main panel, with no problem. If you have a house bigger than that, I have no sympathy for you.

Issues

In one case the receiver identified three different breakers belonging to the outlet pictured above that’s located at the bottom left of the breaker panel. This outlet is wired directly into the service panel. As mentioned above, the signal propagates on the bus bar. I believe that in this particular case, the signal was so strong that the receiver couldn’t differentiate which breaker was the source.

There also were a few times when I couldn’t identify any breaker belonging to an outlet. I ran into this issue about 4 or 5 times over the course of remapping the entire house. In each case I was able to find a work around which I’ll talk about in the next section.

Another interesting thing I learned about the transmitter: Do not put it in your mouth! There is a residual charge left in the transmitter after you unplug it. If this sounds like a really stupid thing to do, it is, and I got zapped.

After I removed the transmitter from an outlet, I had both of my hands full, so put it in my mouth temporarily to hold it, just like you might do with a pencil, flashlight, or other light object. It wasn’t like being bitten by a live wire, but it stung about 10x worse than a 9V battery does when you touch it to your tongue.

You might also feel the urge to hold the transmitter in your mouth when attaching a socket adapter to an overhead light. Don’t. Make 2 trips up the ladder if you have to.

I found the rubber boot somewhat annoying, as it would stick and let go, causing the receiver to bounce along when I was sweeping it over the breakers. I understand that Klein is trying to make the receiver more rugged in case you drop it, but it’s really nice that you can remove it. Once removed, the receiver slid over the breakers more smoothly.

Troubleshooting and Solutions

After some trial and error I found solutions to all the problems I ran into. Stuart also reached out to Klein and got some tips back from Bruce Kuhn, the Director of Product Development.

First, to solve the issue of multiple signals from the outlet attached right near the main panel, I plugged an extension cord into the outlet. My thought behind this was that, if the signal was too strong, making the transmitter broadcast through a longer wire would attenuate the signal enough to eliminate the multiple sources during training.

I was wrong, and the receiver continued to falsely identify three separate breakers as feeding that one outlet.

Bruce had suggested running the receiver over the panel a third time, because sometimes it might need an extra pass to sort out which signal is the strongest. This didn’t work either. The receiver still identified three different breakers after the 3rd, 4th, and 5th passes.

Despite what Bruce told me about the transmitter orientation not mattering, I found that unplugging the transmitter and plugging it in upside down allowed me to identify the breaker for some of the troublesome outlets. It’s unclear why this worked, but I’m glad it did.

Another trick I found that works to identify breakers for stubborn outlets, was to turn the receiver off and back on, and then scan the panel in a different order or direction. If you scanned top to bottom and left to right, try bottom to top and right to left.

After using the receiver for a while I noticed that it made a difference where you scan on the circuit breaker. On my service panel, if I scanned closer to the switch on the breaker, the receiver wouldn’t pick up the signal reliably. I found that if I scanned closer to a terminal lug I got more consistent results.

This also meshed with what Bruce advised: “the receiver works best if you hold it straight up and down, move it slowly, and try to keep it in the same spot on every breaker.”

The rubber boot can also reduce the sensitivity of the receiver, so if you are having a hard time locating the breaker, you could try removing the boot. In my opinion it also makes the receiver easier to use as I noted before.

Final Thoughts

This was a fun little product to review. It helped spur me to take on a project to fix something that has been bothering me since we moved in: how to find which breaker turned off which outlet or light. This brings up another problem though: how to tastefully identify which breaker to turn off when you are at a particular outlet.

I found one really cool way to identify outlets in my shop. Since I only have a few circuits and breakers that are dedicated to my shop, I used a color coding scheme. You can read more about it on my workshop blog.

I painted the three breakers red, yellow, and blue, and then painted the corresponding outlet covers to match.

For the rest of the house, I decided on a numbering scheme since there were so many circuits. I placed a little sticker with the breaker number on the cover plate. I asked my wife if she minded and she said she didn’t, but then again she’s used to living with an engineer.

The wiring in my house isn’t as simple as saying all the lights in this part of the house are on this breaker. I decided to create a floor plan of the entire house, which I figured would help me keep track of all the outlets and lights on a given breaker. In the floor plan, I would lay out and label all of the outlets. After much searching I found a cool program called FLDraw Lite.

This standalone (read doesn’t need to be installed) Windows program allows you to quickly draw out up to 5 floor plans. Above is a rough sketch I drew of our family room using dimensions off the top of my head and about 5 minutes. By keeping a copy of the plans next to the circuit breaker, I’ll be able to find the correct breaker at a glance and also have a good map of the electrical system for down the road when I need to make improvements or repairs.

At $40, the Klein Digital Circuit Breaker Finder might be a little expensive for a homeowner that only wants to find a circuit breaker once in a while. But, if you are a handyman, electrician, or a more hands-on homeowner type, this might be an inexpensive way to save some hassle. Remember to take a little time to learn its quirks, and to train the receiver on your breaker panel.

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Thank you to Klein Tools for providing the review sample unconditionally.