Sparks flew out of my breaker box, probably due to faulty wiring. In an effort to troubleshoot, I removed all the breaker and labeled them. Got a wire tracer and tried to trace the wires to see nothing was cross wired. Got a new 20amp breaker and reconnected one of the outlet that was 20amp. For test sake, I only connected one outlet. Getting a 118.5V reading, receptacle tester is reading correct, yet the fan won't turn.
Suspecting the wires or the receptacle it self may have been damaged, I take a new 14/2 wire, about 24 inches, connect the black to 20amp breaker, white to the neutral bar of the panel and ground to the ground bar of the panel. using a new outlet, I'm getting 118.5v reading and receptacle tester shows its correctly connected. Yet the fan won't turn.
Not sure what else to check. Do I new a new circuit panel? Please help.
The house is little over 40 years old and and the panel is just as old I'm guessing. The panel is Square D QO.
I'm a contractor and have worked with enough electricians and have basic electric skills and knowledge.
The fan was plugged in temporary for testing. The fan is not broken because I tested the fan at my neighbor's house and it works fine there.
I guess my question is can the circuit panel itself go bad, or could it have been damaged when the sparks flew? Everything but the main feed is disconnected so it's safe for me to do wire tracing. I haven't completed the all the tracing yet, but the ones I traced so far are not cross wired and appear correct. And, when I connect those back up with a new breaker and new outlet, get 118.5v reading, and receptacle tester is reading the wires are correct, the fan won't work. The only conclusion I can come up with is the panel has gone bad.
I'm probably going to get a new panel anyway since the house or the panel does not have a main shut-off, and I'm not about to start checking the connection of the panel itself without shutting off the power. But I do want to avoid having to pull new wires through out the house if possible.
So I guess it's now becoming testing for future knowledge, and maybe I can post what I find here for everyone.
So, here are the facts:
– New 14/2 wire
– Black is connected to a brand new 20amp breaker
– White is in the neutral bar of the circuit panel
– ground is is the ground bar of the circuit panel
– other end of 14/2 is connected directly to one brand new outlet
– multi-meter is reading 118.5V
– receptacle tester is showing the outlet is correctly wired.
– But connecting a fan I know works, doesn't turn on.
What else can I safely test until I get the power turned off on Monday?
Best Answer
Big arc flash is big
Sparks flew out from your breaker box. Not from your meter pan, nor from a socket; from the breaker box. I assume you normally keep the cover on it and no gaps in the cover, so sparks getting around the breakers is actually a pretty big deal. This is a big arc flash.
So I would expect it to leave big evidence behind. And where I would look is
I would expect a scorched main lug or burnt wires where the supply wire meets the lug.
Once the power is turned off, get the correct tools and try torquing down each of the lug screws. Pay very close attention to the amount of torque needed for the screw to start moving - you must do this "by feel", a click-type torque wrench is for setting torque, not measuring it. If any lug is significantly looser than another, then gotcha. Certainly do not do that with the power on; I don't know about you but all my hex sockets are made of metal :)
Then I would remove all of the wires from those lug screws, pull them back and inspect thoroughly for any sign of arcing damage. Any damage is call for replacing the lug and nipping back the wire just enough to seat it on clean wire. Don't fail to replace the lug unless physical inspection reveals it to be perfect.
QO is a fine, modern industrial tier panel and its quality is beyond reproach; however if a lug were improperly torqued, that would cause this. Reapply anti-oxidation paste to the aluminum wires and reattach. If you found improper torquing before, this should be the end of it.
If you are replacing the panel, replace with another QO so you don't have to buy all new breakers, unless there's some amazing feature of a competing panel that you really, really need. (Bolt-on-neutral and cheap generator interlocks are not two of them because QO has those).
Buy the biggest panel you possibly can
And buy a 40/42-space panel unless it simply will not possibly fit. The cost difference isn't that much over 20/24 space panels, and that assures you'll never ask "My panel is full. How do I add this circuit?" That is the #1 panel related question around here, and it's so easily avoided, and right now is the time to avoid it.