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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7667
Experience:  Proven Professional 48 years Experience
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I ust installed a 240-volt breaker for a dryer at a house

Customer Question

Hi there, I ust installed a 240-volt breaker for a dryer at a house and for some reason the drum of the dryer turns but the heating element doesn't work. The receptacle and dryer nstructions said to wire as non grounding circuit-meaning use neutral instead of ground which I did. When I checked the power 1 hot leg is 120 and 1 hot leg is 107. The neutral looks ok-doesn't have power on it. And for some reason the heating elements in the oven and the other laundry room dryer also don't work now. So somehow I jacked up anything that works off 240 power in the house. I reset all 240 Breakers, disconnected the new breaker, and still no joy. Any ideas?
Submitted: 1 year ago.
Category: Electrical
Expert:  Mike G. replied 1 year ago.

Hi, I'm Mike G and I'll be assisting you. I suggest testing the breaker pole to pole for 240V and each pole to the neutral bar for 120V each. Let me know your readings.

Customer: replied 1 year ago.
Thanks Mike,
Will do
Expert:  Mike G. replied 1 year ago.

One more thing. Turn off all other breakers but not the main and retest. That is to see if the low voltage is a feedback.

Customer: replied 1 year ago.
Ok I'll do that. When I rechecked power I now have 116 volts on one pole and 120 on the other and when I checked pole to pole I have 4 volts. The difference between the two. There is no power when I checked neutral to ground.
Customer: replied 1 year ago.
When I turn off all other Breakers and check the new one I get 120 and 113. When I flip other Breakers back on I get 110 and 120 and pole to pole 10 volts.
Expert:  Mike G. replied 1 year ago.

Test the terminations of the incoming service wire with only the main breaker on. Then test the bus's after the main, pole to pole.

Customer: replied 1 year ago.
FYI I'm working at a sub panel so when you say kill the other Breakers do you mean just the sub panel other Breakers or all Breakers at the main panel too? Also before putting this new breaker in there has been no previous problems with 240 volt appliances and even now with the breaker disconnected and pulled out of the panel the problem remains with the other two appliances,
Customer: replied 1 year ago.
Why do you think I'm not seeing 220 to 240 volts pole to pole when I'm working with Two-phase service at the sub and Main panels?
Expert:  Mike G. replied 1 year ago.

Bad breaker or bad connection. You'll need to check the service main if the reading are low at the sub feed main. Check before and after the main the same way.

Customer: replied 1 year ago.
Turns out the main breaker was half tripped so that's why it only affected the 240 stuff-I shoulda checked that first, huh?
Customer: replied 1 year ago.
Now I have a full 240 pole to pole at all 240 Breakers at Main and sub panels thanks for the help.
Expert:  Mike G. replied 1 year ago.

Need to take it a step at a time. You're welcome.

Customer: replied 1 year ago.
I appreciate it! You did lead me to check the main, the half tripped thing is what stumped me,
Expert:  Mike G. replied 1 year ago.

Very good. You now know about feed back on a 2 pole when one leg is dead.