Determine breaker for electric baseboard


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Old 12-16-16, 12:05 PM
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Determine breaker for electric baseboard

I'm planning on replacing an existing wall mounted thermostat and 240v electric baseboard heater. How do I safely determine which breaker they are on? (panel is not well marked).

I was planning on carefully removing the cover from the stat so I could see the wires. Next, take a non-contact voltage tester to make sure power is coming into the stat. Next, turn off one breaker at a time until I no longer detect power.

Once I determine the correct breaker I will fix the label on the panel.
 
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Old 12-16-16, 01:52 PM
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That's as good of method as any for the screening process. Always verify the test with a real contact tester or multimeter before sticking your fingers in the box.
 
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Old 12-16-16, 03:09 PM
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You could also turn all the breakers off and turn one on at time. Wait to see which heater start to get warm. Repeat as necessary.
 
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Old 12-16-16, 03:16 PM
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Do not waste your time with a non contact meter, use a real volt OHM meter.
Why waste time waiting for a baseboard to cool down?
With a real meter, hit the breaker the power goes to 0.
 
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Old 12-16-16, 05:57 PM
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I was planning on carefully removing the cover from the stat so I could see the wires. Next, take a non-contact voltage tester to make sure power is coming into the stat. Next, turn off one breaker at a time until I no longer detect power.
This is definitely what I would do.
I think this case would be a perfect use for a non-contact tester. I don't know why there are so many replies discouraging non-contact tester. It cannot replace multi-meter, but it works great when used properly.
You can verify with multi-meter once you find breaker, but I feel confident with non-contact tester only.
Just make sure your non-contact tester is actually working by testing on known live circuit first.
 
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Old 12-16-16, 07:27 PM
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Remember that since it is a 240 volt heater, it should be a double pole breaker (if not you have other problems) so that should limit the number to try.

My experience with non-contact testers is that they sometimes false alert from a stray field, but mine has never failed to alert when AC is present. Nevertheless, I confirm with a meter if I'm doing anything more than identifying a circuit or the like.
 
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Old 12-19-16, 11:24 AM
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I would second (third) the use of a non-contact tester. You can likely get it to work on the thermostat without removing the cover. Easy peasy!
 
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Old 12-19-16, 11:49 AM
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So I tried my method this weekend, I showed a helper how to use the non-contact tester and I ran down to the basement where the panel is (thermostat is on 3rd floor). Turned off every 20 amp double pole breaker I could find, and according to my helper, the tester still showed power at the thermostat.

The only double pole breakers left were 30+ amp which were for my stove, heat pump air handler, etc.

I might repeat the process without help so I can verify for myself. If I still can't find it, then I'm calling in a qualified electrician.
 
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Old 12-19-16, 11:59 AM
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Not code but it could be on two single pole breakers. Start by turning off all 20 amp single pole breakers and see if it kills the power. If so try turning the single pole breakers on one at a time. If one shows power turn it back off and try the rest to find the second breaker. If turning off the 20a breakers does nothing repeat with the 15 amp single pole breakers.
The only double pole breakers left were 30+ amp which were for my stove, heat pump air handler
It would be unusual to have a stove on a 30 amp breaker unless you really mean cooktop. If it is a allegedly for a stove I'd test that breaker. Still nothing all the 30a breakers.
 
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Old 12-19-16, 01:34 PM
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Ray...I will give that a try.

As for my "30 amp breaker" comment...I just meant that there were several double pole breakers left that were all either 30 amp or more. For example, 40 or 60 for various other items in the house...dryer, air handler, etc. My apologies if I wasn't clear. Thanks for the idea!
 
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Old 12-22-16, 05:39 PM
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So...I called in reinforcements...a friend who is master electrician. He came over and did some troubleshooting for me. After installing and testing a new thermostat, it turns out the 20 amp, double pole breaker was not installed in the panel correctly. If I can explain this right, both sides of the breaker were on the same phase.

He moved the breaker in the panel correctly and then VOILA...heater worked.
 
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Old 12-22-16, 06:48 PM
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Must have been a GE breaker panel and a half size two pole breaker. Lots of people have been there, done that.
 
 

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