Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Using a voltage detector I determined that three breakers in the panel are not conducting voltage, yet they are fully on (not tripped). Thinking they were bad, I replaced a double throw 15 amp and a double throw 20 amp in the box. Flipped them on, still no power coming out of the new breakers. What could cause this?

share|improve this question
1  
When you were replacing the breakers, did you happen to notice any damage to the bus bar to which they connect? WARNING: Do not physically touch the bus bars, visually inspect them only. Does your panel have two continuous bus bars, or is it a split bus panel? A picture of the panel with the cover off, might be helpful. –  Tester101 Aug 26 '13 at 12:09
1  
You really should have tested if there is voltage AFTER the breaker and BEFORE the breaker before replacing anything at all! If there is no voltage before the breaker refer to testers comments. If you had no voltage after the breaker then faulty breaker, replace. But if you have voltage before and after it is obvious there is a sub panel somewhere or severe damage has occurred to the supply lines (rat eating them, over loaded and melted or got cut somewhere.) WARNING There might be LIVE but not GND in the sockets. Use a self grounding screwdriver to test for LIVE. BE VERY CAREFUL! –  ppumkin Sep 23 '13 at 13:38
add comment

3 Answers

First, do the easy-to-check steps: does a device that should be on still work? Is the "on" switch on? Is it plugged in? (Children are often noted for unexpectedly changing these.) If the device is plugged in somewhere else, does it work? Does a portable device known to work properly suddenly not work in the alleged "failed" outlet?

Next, are you sure the breakers have not tripped? Many manufacturers build them so that they do not visibly change when tripped. To be sure, turn the lever all the way off and then back on.

Three circuits! There is very little in common such that only three circuits with three separate breakers are all affected. Maybe there are more? Are there any other circuits which are on the same bus in the breaker panel also not working? That would indicate a bus being disconnected, probably by a loose wire inside the panel. A visual inspection with the panel cover off might be helpful.

Also possible—maybe probable—is that some neutral wires have come loose in the panel. Turn off the main breaker and give all the wires a wiggle, being very careful not to touch near the service wires or where they connect to the main breaker.

Maybe something changed recently?: Electrical work, ground work, utility work.

share|improve this answer
add comment

The breakers are 240 VAC double pole breakers. If you put a voltmeter on the 2 wires, do you read 220-240 VAC? If you put a voltmeter from either of the breaker wires to ground or neutral, do you get 115 VAC?

When you say no power coming out do you mean the equipment connected to that outlet doesn't work? Even if the voltage is correct?

Look at the connection between the breaker and the panel bus (how it plugs in to the bus). I recall a time when a 2-pole breaker was not contacting both panel legs (the metal bus, there are 2 of them for each side of the 240VAC, 120VAC on each bus).

share|improve this answer
add comment

I'm betting one half of your main breaker is tripped. Have you reset your main breaker? (At the top?)

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.