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Inactive, Master Electrician
Category: Electrical
Satisfied Customers: 4772
Experience:  Electrical Contractor
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I am installing a 240v construction heater in my garage. The

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I am installing a 240v construction heater in my garage. The recepticle has 2 hots and a ground. I have a double pole 30 amp breaker connected in the panel, with 10 guage 2 wire cable. For some reason the heater does not work. I verified the heater works at a friends place. I tested each hot at the receipticle and each show 110-120v individually. What could be wrong?
Test the wiring line to line - tell me if your getting 220v
Customer: replied 8 years ago.
Not sure how to do this - sorry first time wiring for 220. My voltmeter has 2 wires, a + and a -'ve. When I put the -'ve to ground, and +'ve to either hot, I get 110-120 on each. How do I test for 220? Do I put the +'ve against both hot wires?
What you do is take and put one lead on the black and the other lead on the white.
Customer: replied 8 years ago.
Ok, between white and black I get no reading. Between ground and white I get 120. Between ground and black I get 120. In the panel I have the ground on the groun bar. The white and black to the double pole breaker. On the receipticle, I have ground to ground. And white to one hot and black to the other hot. Is this correct?
Ok at the breaker panel, test the breaker - one lead on one terminal and the other lead on the other. If the breaker is bad - you will not get 220v.

Pictoral Illustration:
Customer: replied 8 years ago.
Same result as with plug. From either terminal to ground, I get 120. When leads go to both terminals I get nothing. This is a subpanel wired in using #6/3 from my main panel. Main panel has 60amp double pole to connect sub panel. I believe I wired that correctly, but maybe not. In main panel I have red and black on the 60amp breaker, ground in ground, neutral on neutral bar. I think subpanel is right because I have normal 120v's in there working fine... Any other ideas? Do you think the 30amp breaker in the sub panel is bad?
You can confirm your subpanel wiring by placing the leads on your main incoming lines. See diagram:
Customer: replied 8 years ago.
On the incoming lines to the subpanel. Black to white gives 110/120, red to white gives 110/120 and back to red gives 220/240... so this is right? Does it mean my 30amp breaker is bad in the subpanel? All breakers, wiring, panels etc are brand new by the way.
Yes if you have 220v on the mains, but not on the 30amp - then your double pole 30amp breaker is bad. You will need to replace it.
Inactive and other Electrical Specialists are ready to help you
Customer: replied 8 years ago.
Ok thank you for your help! I was 99.9 percent sure my wiring was right, but now I learned a lot about trouble shooting! Have a great night!

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