Troubleshoot Electrical Panel


About 10 years ago I bought a Square D 100 amp electrical panel and some breakers at Home Depot and had an electrician replace my old box. I suspect that one bus is not energized because last night, a number of lights and outlets throughout the house stopped working. After I flip the main breaker, remove the cover, and verify that both incoming hot wires are tight, what else can I check for?
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Check to see that you have 240 volts between the two hot wire before the main breaker. If you don't, the problem may be a loose connection outside, in the meter box, or with the utility company. If you do, check to see that you have 240 volts on the load side of the main breaker. If you don't, you have a bad main breaker
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Thank you very much! One leg feeding the meter is down so it's Entergy's problem.
What causes this? Is there something wrong with the neighborhood transformer?
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Thank you very much! One leg feeding the meter is down so it's Entergy's problem.
What causes this? Is there something wrong with the neighborhood transformer?
More likely a bad connection on that leg. It can occur anywhere between your meter socket and the transformer itself, usually at some junction or splice
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Danger Danger Will Robinson!
Even after you flip the main breaker, the incoming hot wires are STILL HOT, and you can be fatally shocked from touching them. Some main breakers use standard screws to hold down the wires; the plastic handle of a screwdriver affords adequate insulation. Other main breakers use socket-head screws; if you stick a hex key (aka Allen wrench) into one of those, you may turn yourself into a crispy critter.
The very first thing you should do, even before flipping the main breaker, is check the voltage between the two incoming hot wires. If it's not somewhere between 220 and 250, then call your utility company -- it's their problem.
If it *is* between 220 and 250, then the problem is in your house somewhere. With the main breaker *on*, measure the voltages between the two buses (should be approximately 240) and between each bus and ground (should be approximately 120 each time). If not, the main breaker needs to be replaced -- and you *still* need to call the utility company. As noted above, those incoming wires are hot. You want the utility company to pull the meter before you change the breaker, and reinstall it after you're done.
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On Aug 16, 8:13pm, snipped-for-privacy@milmac.com (Doug Miller) wrote:

Thanks for the warning. I knew the leads were both hot and opened up the meter to find the master switch. But since the problem was upstream, I decided there was no need to go on.
Entergy installed a portable powered transformer to energize both sides of the box and the guy verified that my socket head screws are tight. He said there is a break between my meter and the underground box at the back of my neighbor's yard. A crew will be out later this week to find and fix it. If the break is close to the house (likely because we have some settling), they will probably need to remove part of a brick over sand walkway; I suppose the edge of the slab may also be involved.
My wife wants to know what we should expect about them restoring the yard after they restore electrical service.
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Later this week??? Is this in a rural area?

The yard should be restored, although that might consist of raking soil and spreading seed. The walkway should be restored, too, if it's not in the utility right-of-way. If it is, they probably have no obligation to restore it after they're done. They might anyway, but don't count on it.
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Doug Miller wrote:

Heads-up - the way a utility restores grass is usually hydro-seeding (the sickly green stuff, like you see on the side of the road), done by a subcontractor. The seed loaded in the mix is often not weed-free, and usually includes fast-grow varieties that may not come up the following spring. With my crappy yard, I wouldn't care, but if you have a show-off lawn, you may want to discuss it with them, and have them just rake it as smooth as they can. You could then handle the finish raking, addition of the clean topsoil, and hand-seed.
As to walkways and slabs- for brick walk or patio, don't count on a lot of careful substrate prep, or fine tuning to make the area level. You may have a lump or a valley come spring, and have to touch things up. If they can come in from the side or re-route, they will. If house is on a slab, they probably will not need to disturb that, as long as they can get to where the conduit comes out underground.
-- aem sends...
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