Test double pole 20 amp breaker

17 years ago

I don't have a tester. I have a 20 amp double pole breaker. I don't know if it is working or not.

If I hard wire in a light to the end of 12/2 wire coming from the circuit breaker can I test if the circuit is working or not (light comes on when circuit breaker turned on)). OR...is something like this too much juice and it pops the light? I've checked circuits doing this before but always just for a single pole 15 amp breaker.

thanks

Sort by:Oldest

Comments (10)

petey_racer
17 years ago
I'm sorry, but if you don't even have a decent tester capable of at least 250 volts, you really have no place working in a panel.

If you insist on doing this go buy a tester. A reasonable one can be had for about $25.
DavidR
17 years ago
Test from each terminal of the breaker to the neutral bar or ground bus.

You really should have some kind of test device. At least get a cheapo neon test light. I like using a 25 watt incandescent bulb in a rubber pigtail socket too, as this provides a load to prevent false readings. You might want to use a silicone coated bulb for durability.

Or just get a Wiggy.
Related Discussions
Should a 30 amp, 2 pole breaker be hot on both "breakers"?
Q
Comments (6)
A non contact tester and even some digital volt meters are not all that reliable in crowded wiring. A DVM's input impedance is often so high it can pick up 'stray voltage' by capacitive coupling, the same 'trick' that non-contact testers use. Luckily the error is usually to indicate voltage is present when it is NOT actually there. It can make trouble shooting a PITA though when it says dead circuits are still live.
...See More
30 amp breaker okay for this double oven?
Q
Comments (8)
Thanks for the feedback! The specs from that Sears site are backwards it looks like. It certainly would be 33 amps at 240v, so a 30 amp breaker won't work. I wish we could run 8ga wire to the oven location, but it's not a possibility. Sure would open up more double oven options for me! In my shopping, I'm still surprised that some specs call for a 40amp outlet, even though the calculation of max Amps (Watts divided by Volts) equals less than 30 amps. (ie some ovens are max rated at 6700 watts @ 240v = 28 amps, but the specs still call for a 40 amp outlet.) Is there something I'm missing here?! I don't want my 30amp breaker tripping all the time if I'm miscalculating, but it would sure be nice to have some other oven options than what I'm currently looking at.
...See More
Replacing double pole breaker with two single pole
Q
Comments (12)
So, I think it's clear I was mistaken about how the 240 and the 120 work. I did a little more homework after reading DavidR's last post and got it, I put the white on the bus bar and the black in the new breaker. It took some swearing and bending, but I did get the 10 wires on the receptacle firmly. Got it all put back together and it works! Was pretty nervous, it being my first time in the panel, but it went so smoothly. The hardest part of this whole thing was getting the panel cover back on! Thanks to you all, for helping me with a new skill!
...See More
5500 Watts on Double 25 Amp Breaker?
Q
Comments (8)
@bryanthegrower: "Hire an electrician for the sake of your family if not yourself." Oh, come on. He's just checking to see if he's buying a water heater his 240 volt circuit will support. And you don't need an electrician to install a hot water heater. Connect three wires and you're done.
...See More
bus_driver
17 years ago
If you are wanting to see if the breaker will trip, the first test David suggests will do the job. But it is crude and leaves some permanent damage at the points of contact. If you decide to do that, wear a full face shield. It can be a substantial blast. I think the others posting are really thinking of using a tester to determine if voltage is present at the breaker terminals, a much gentler test, but it tests only for continuity.
lanelu46
17 years ago
Sorry "bus driver" don't know what the hell you were talking about but David was saying to take a temporary lighting socket that comes with wires and to take the White wire on his light to the ground/neutral bar and then take the Black lead to phase A of his breaker and the light bulb will light( if there is power). Then take the black lead to phase B(the other terminal on the breaker) and if there is power there the light bulb will light. And no the 20A breaker is not to much juice to blow the bulb.
Don't know what the hell you were talking about but the other post were telling him to buy a cheap VOLTAGE tester to check if he had 120v to ground per phase then check phase to phase to see if he had 240v. That means the breaker is good and its hooked up to 2 differnt phases. Now if he bought a tester with a setting for continuity and set it to that and touched it to 120v-240v either it would blow an internal fuse in the tester itself or blow up the tester.
***Highly agree with "petey", If you don't even have a decent VOLTAGE tester you shouldn't be in a panel.***
greg_h
17 years ago
Umm, lanelu46, I think your response to bus driver was a little off base. I think he was thinking that David was saying to touch a wire from one hot side of the breaker to the neutral or ground bar, thus creating a short. This is highly unadvisable, and probably not what David meant (as you pointed out).

Just because you don't understand what he was saying doesn't mean you should blow up at him.
bigbird_1
17 years ago
David's method will not cause a short. He has a load in the cc't.
Lanelu: Why are you talking about blowing a meter doing continuity? Nobody ever mentioned a continuity test, only a voltage test. If someone doesn't know that you never check continuity on a powered cc't, then they have no business using a multimeter.
DavidR
17 years ago
No, I was NOT suggesting that he test the breaker by shorting it to neutral. From the OP it sounded like he just wanted to know whether the breaker was closed and conducting. I suggested using a 120v test light, from hot terminals to neutral or ground. Sorry if that was unclear.

Other than an appropriately rated switch or contactor, I can't think of any safe way to test a breaker to see whether it trips under short circuit fault current. Shorting a wire to neutral or ground is hazardous, and I would never recommend it.
bus_driver
17 years ago
The original post did not make clear what characteristic the testing was supposed to reveal. One would be continuity and the other would be an ability to trip on overload. My tongue-in-cheek attempt to point out the potential danger of testing by short circuiting the output of the breaker was misunderstood. I should have known that someone would not understand and that turned out to be the case. Of course david never suggested short circuiting the breaker.
brickeyee
17 years ago
Tghe magnetic trip portion of the breaker is actually the easiest part to test. This is the part that responds to a short circuit and kicks in around 200% of ful load.
The thermal trip is the harder one sionce there is a pretty decent range of overload times that are in specification.
This portion is active from 100% up to about 200%, but the two systems are both running in parallel and being thermal and mechanical at the same time have friction that varies from device to device.
By 200% the magnetic portion develops a pretty decent force and trip times become more consistent.
DavidR
17 years ago
My tongue-in-cheek attempt to point out the potential danger of testing by short circuiting the output of the breaker was misunderstood.

You forgot the smiley. ;-)