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Low Voltage after switching breaker off to high voltage thermostat.

Low Voltage after switching breaker off to high voltage thermostat.

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Old 05-01-19, 06:33 PM
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Question Low Voltage after switching breaker off to high voltage thermostat.

I'm planning to change my high voltage thermostat connected to an electric baseboard heater to a high voltage smart thermostat. My problem is that after switching the breaker off to that thermostat, low voltage is showing on the Klein Tools dual range (MCVT-2) non-contact voltage tester. If I set the the Klein to just high voltage setting, there is no response. I don't want to touch the wiring until I'm sure that no power is running through it. Is there another voltage tester that I could use to confirm this? Our house was built in 1979 and the breaker box was changed maybe 15 years ago by a licensed electrician. We have never changed any of thermostats before. I know they are not very accurate and would like to eventually change them all. Never had any trouble changing the electric baseboards in kitchen and 2 bathrooms by turning the breakers off. Any suggestions are welcome.
 
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05-02-19, 07:55 AM
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Welcome lioneye to the forum. A cheap digital multimeter will be affected by the same ghost voltage that causes misleading results from a non contact tester. A digital meter that isn't affected by ghost voltage is very expensive but a cheap analog solves the problem without breaking the bank.

It doesn't help members to contradict advice which over time has proven to be very helpful to users. Wait till you spend days helping a user when they swear they have 120v at point A then find out they were using a non contact tester and in fact point A is dead. Or try explaining why a user has 24v with the switch off when in reality it is ghost voltage because he used a digital meter.
 
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Old 05-01-19, 07:42 PM
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voltage is showing on the Klein Tools dual range (MCVT-2) non-contact voltage tester.
Non contact testers are only slightly better than a
toy. Use an analog (not digital) multimeter.
.
 
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Old 05-01-19, 08:18 PM
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Thanks Any suggestion on a brand?
 
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Old 05-01-19, 09:39 PM
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The home improvement centers carry basic analog meters starting around $15. That's all you need.

Analog meter at the depot
 
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Old 05-02-19, 07:39 AM
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The Klein tester you have is a good tool. Not a toy. That said, it is a good idea to confirm with a meter. Doesnít have to be analog. Digital is fine. This isnít 1970. Always a good idea to test it on a known live circuit (a receptacle for example) first. What your likely picking up is a very small amount of inductive voltage on the conductors. Prob in the >10 v range.
 
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Old 05-02-19, 07:55 AM
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Welcome lioneye to the forum. A cheap digital multimeter will be affected by the same ghost voltage that causes misleading results from a non contact tester. A digital meter that isn't affected by ghost voltage is very expensive but a cheap analog solves the problem without breaking the bank.

It doesn't help members to contradict advice which over time has proven to be very helpful to users. Wait till you spend days helping a user when they swear they have 120v at point A then find out they were using a non contact tester and in fact point A is dead. Or try explaining why a user has 24v with the switch off when in reality it is ghost voltage because he used a digital meter.
 
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Old 05-02-19, 09:57 AM
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Thanks. We just might still have an analog tester somewhere around the house. If not, I'll just go purchase one. I do understand about ghost voltage. Just want to play it safe.
 
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