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Discussion Starter #1
I lost power to half of my breaker box. When I check the voltage to each lug on the main breaker, I only see 120 on 1 side of the breaker. Is that normal? If I measure the voltage between the two lugs I get 120. Is my problem at the main breaker or maybe out at my power pole? Thanks.
 

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It could be on the POCO side or in your side.

You should have 120v on each leg, and 240v between them. Is it possible that the lug for the main breaker is broken? I had that happen once, and every other breaker was dead.

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I lost power to half of my breaker box. When I check the voltage to each lug on the main breaker, I only see 120 on 1 side of the breaker. Is that normal? If I measure the voltage between the two lugs I get 120. Is my problem at the main breaker or maybe out at my power pole? Thanks.

Check both the LINE and LOAD sides of the main breaker. For the LINE side, check it where the power comes in from the outside to feed the main breaker. The LOAD side would be points after the breaker, such as the voltage between the two bus bars, as well as each busbar and ground.


If the problem appears only on the LOAD side and not the LINE, then the problem is a bad main breaker. I just had a service call last week to change one that went bad. If the problem is on the LINE side, then you need to call your POCO to see if it's on their end.
 

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Discussion Starter #5
There is copper sticking out of the lug, so I put my test lead there and still get 0 volts. Testing across the copper and to the other side of the breaker I still get 120.
 

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I lost power to half of my breaker box. When I check the voltage to each lug on the main breaker, I only see 120 on 1 side of the breaker. Is that normal? If I measure the voltage between the two lugs I get 120. Is my problem at the main breaker or maybe out at my power pole? Thanks.
It could be a bad breaker or a power company problem. Check the voltage at the top of the breaker where it comes in from the electric meter. If you have only 120 volts there contact the power company and tell them that one leg is dead.

If you have power on the top, but not on the bottom of the main breaker, then the breaker has a problem. You could try shutting it off and then pushing it back on. That may fix it temporarily.

How old is the main breaker? What brand name is the main breaker?
 

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Discussion Starter #9
There is a service disconnect in a box after the meter. Could that be the problem? Will the POCO be able to tell me since its after the meter?
 

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There is a service disconnect in a box after the meter. Could that be the problem? Will the POCO be able to tell me since its after the meter?
Yes the problem could be there. Do the voltage measurement on both the line and load side of the disconnect.
 

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The breaker is 30 years old and is a Bryant. The top lug has 120. The bottom lug has 0.
If it is a Bryant it is probably older than 30 years. It sounds as though that is the problem. Call the power company anyway and have them confirm since it won't cost you anything. I don't know if replacements for Bryant main breakers are available. There may be a catalog number for the breaker on a label inside of the panel.
 

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Discussion Starter #12
Just checked the disconnect and its there. Can the power company turn off my electricity without coming out since its the weekend?
 

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Just checked the disconnect and its there. Can the power company turn off my electricity without coming out since its the weekend?
If power is at the disconnect, use the disconnect to turn off the power to the main panel.
 

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Discussion Starter #15
Its the disconnect that's bad. The power coming in is good, but only one side coming out has juice. That's why I asked about the power company.
 

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In an emergency they would come out. I don't know if this is an emergency. You would need to contact them.
Around here you would need to schedule the disconnect, inspection and work so that it all happens on the same day. Some electricians here are self inspecting so they will schedule the disconnect, do the replacement and then call for the reconnect.
 

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The OP has got all the right replies so far, nothing here to add but just a note. The OP needs to turn off any 240 volt loads like the 240 volt central air conditioning outside condensing unit, if his home has one.

And the 240 volt electric water heater or clothes dryer if he has them. The AC outside unit can be damaged (if it does not have voltage/phase loss protection) trying to operate the compressor on 120 volts.

And the WH /dryer may seem to work on 120 volts, but it is really going to put them in harms way trying to operate them on 120 volts. JMO
 

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Can you post a photo of the disconnect? You may be able to change it yourself in about five minutes rather than waiting for the power company.
 

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Discussion Starter #20
Thanks everyone for the replies. Attached is a pic of the disconnect. The two wires at the top are live with no way to kill the power but removing the meter.

On a side note, what caused this? Well I was hooking up a water heater. Simple thing. Attach the my 2 hot wires to 240 breaker and attach ground wire to ground strip. I turned it on and had no lights. Troubleshooting showed half my breakers were off. Could I have caused this and if so how? Nothing tripped, just no power on half my breakers. Thanks.
 

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