Hey all,
So I’m going to be cleaning behind the wall heaters in my house, because I’m not sure WHEN they were last cleaned… and almost nothing is labeled in the circuit breaker box. So I’ll DEFINITELY need to be sure the power is off to each particular heater before messing around with it. Here’s the question.
That tool should work for you as long as you have some access to the power wire. I have a Greenlee brand tester that is essentially the same. I do prefer to use a multimeter if there is access to test points, but that unit will work.
That said, I like to test it first with the circuit ON, hear the tool chirp and light, and then turn the circuit off and check it again.
Just keep in mind that with that kind of voltage tester, you have to get pretty close to the wire, within a few inches, to get a positive reading. Test it first on some circuits that you know are live so you get a feel for how close you need to be.
That type of analyzer is a good first check… But a poor substitute for a final determination of circuit condition. Use a real meter for the actual determination of hot VS not.
I am concerned that any places wiring may be more complicated then the tester helps with.
Maybe because of north america’s dual 110 240 systems but maybe just because these things can be deceiving…
If the OP had to ask about meters, then they can’t work out how to use it SAFELY.
Its possible to forgot the correct order or mix up which circuit breaker should be left on or off…
Electricians actually learn about circuit breakers and household wiring BEFORE touching them.
One electricians trick is to use a thick insulated stranded wire, or solid core with the end teased out to make a thin strand… and touch one end down to one supply wire and then brush the thin wire at the other end down to short the circuit to the other supply wires. If the thin strand touched down sparks and burns away, its still live…
And then when you are sure the supply wired are off, disconnect the wires … ensuring if the supply side is disconnected from the connection block, the end of the wire is insulated and safe…
I recently purchased this handheld DMM for home use. It has a Non-Contact Voltage (NCV) Detector built in to the unit.
I tried out the NCV function after I purchased it. I held it up to a live 120 VAC receptacle. It indicated voltage.
So is an NCV measurement “just as good” as a voltage measurement made by touching the probes to wires? I don’t know. I’ve been doing electrical stuff for a long time, and I have developed a trust for a true galvanic connection. I guess I am skeptical of the reliability of these newfangled toys the young ones are using nowadays. So until I am convinced of their reliability, I will always touch the probes to the copper.
This meter also has a really cool feature called “LoZ.” When invoked, this feature offers a low input impedance when making voltage measurements, thereby allowing you to detect leakage problems.
I have a similar non-contact tester and it works pretty good. Still I wouldn’t trust my life to it. You might want to turn off all the breakers then use that tool just to make sure power is really off.
Then you could turn on the breakers one at a time to see what controls what. Then mark them for future use.
I regularly do home electrical repairs … simple stuff like replacing outlets or water heaters … I use a little 110V circuit tester (Picture) … works great where I can get easy access to the connections …
First I make sure the circuit tester works when the breaker is on … then turn off the breaker and test again making sure it’s off … but most importantly I treat the circuit as live, whether it is or not … for a typical 110V household circuit, there just one wire that’ll electrocute me, so I avoid touching it the best I can … it takes longer to do the job at hand but that’s better than “getting your bell rung” …
So the OP’s device would work just as well … if it shows a true positive, then there’s a very good chance it will also show a true negative condition … and still be careful and work slowly …
Thanks for all the advice! I’m a MAJOR major believer in reading the manual. Many, many times. Never touching anything until many hours have been spent on reading the manual, going online and asking questions in forums, watching a lot of YT videos, etc etc etc. (My grandpa was an electrician; he just kind of never taught me anything… burning social issues such as why not should probably be left for other boards.) But if I don’t do something and start somewhere, these wall heaters will never be cleaned. And they really need to be cleaned.
The reason as to why circuits in the breaker box weren’t labeled… it’s a long story… but I had nothing to do with it. Believe me, we don’t want to get into the whole situation… I actually typed it out and then thought better of it. This thread would probably get moved to great debates, and I don’t think I want to do that. The point is that WHATEVER I need to do to learn how to do this, I’ll do it, and I have to-- because nobody else is exactly going to be stepping in and doing it. I just need to know if I’m starting out with the right tools.
It would take a couple of hours to completely map out your breaker box … just make clear all outlets so you can test them … sketch out a map of your house … then flip a breaker, test each device, note on map … you’ll end up with one double gang breaker which will be your water heater … finish by making a pretty colorful chart that will tape up inside the breaker box cover … get the SO and kids involved and make it a family project …
Well, the SO and kids will be hard to round up, because they don’t exist. I’m not expecting a lot of help from the cat. :rolleyes: Maybe my sister… But no matter what, I absolutely will take a day and do that. My only question is: do I need to have the multimeter TO map out everything? Or no?
I would never do that with 110V house voltage … but I’ve done it with 15 or 20 volt signal voltages … if it tingles we’re getting signal through … if it don’t we’ve an open someplace … it’s a good way to track down a problem if we were to happen to forget the o-scope back home …
I’d be surprised if built-in electric wall/baseboard heaters are on 120 volt circuits. Usually, they’re on 240, so they’re controlled by double breakers. If you flip all double-wide breakers off, there’s a very good chance you’ll cut power to all the heaters as well as the air conditioner, kitchen stove and clothes dryer. (assuming they’re electric, rather than gas)
Digital voltmeters are almost always useless for troubleshooting or testing 120/240 volt circuits as their high input impedance will pick up phantom voltage. IME, a typical digital meter will show around 30-40 volts on a wire that’s actually de-energized. A digital meter with a low impedance or low-z mode would be usable, as would the classic (and sadly discontinued) electrician’s tool known as a Wiggy or solenoid voltage tester.
Oh, and I don’t think anyone else has mentioned yet: When working with wiring, you always want at least three degrees of safety. That is, take three different measures such that any one of them, if it works, would be enough to guarantee your safety.
Everyone got the first one — turn off the breaker
I mentioned working as though the circuit was on — work with one hand in your pocket
That leaves taking off all your jewelry … last thing you want is your gold necklace falling out of your shirt and shorting out through your brain — and that wedding ring is of no use if you fry off your ring finger …
So until I am convinced of their reliability, I will always touch the probes to the copper.
The point is that WHATEVER I need to do to learn how to do this, I’ll do it, and I have to-- because nobody else is exactly going to be stepping in and doing it. I just need to know if I’m starting out with the right tools.
