Hi, all. I’m looking for some advice regarding what I think was a power surge. (Being a carpenter, I know very little about this, so sorry in advance for the long post.)
Last night, my wife & I were out, & when we came home there were several fire trucks blocking our street. When we were finally able to park, we talked to a few neighbors outside, & discovered we were without power. Apparently, the Edison lines behind us & across the street had started arcing, & caught fire.
What’s odd is that there were only scattered houses that lost power. Our neighbors on either side, for example, still had theirs. Upon entering our house, we noticed a very strong smell, almost like burning electronics. We checked, but nothing appeared to have caught fire.
This A.M., we finally got power back, but noticed only about half the house was on. I checked the breakers, & almost half were tripped. After resetting them, we then discovered we still had no air conditioning, & our cordless phones & fax machine weren’t working. I called our electrician who does the work on our remodeling projects, & he said it sounded like a neutral was lost, allowing 220 v to run throughout the wiring in the house.
My question is, what kind of damage should I be looking for/expect? I haven’t had a chance to check every fixture/outlet/device in the house. Is there anything in particular I should check? Anything I can do to prevent a recurrence in the future?
Thanks for any help.
Replies
What I am surprised is that you did not mention asking the FD to check when you had the smell.
There are a number of potentional issues here.
If you lose the neutral then what would have happened is that Instead of a some 120 loads being between one hot leg and the neutral and other loads between between the other hot leg and neutral the the groups of 120 volts loads are in series between the 240. Now if the loads are identical then there will be 120 volts on each group.
But say you have a charger for a cell phone on one side and the refigerator on the other side. When the refigerator tried to run it would be a very low resistance load and most of the 240 volts would be across the charger. It would probably burn out.
But I don't think that in general that it would cause that many breakers to trip.
And the AC is not working, which does not depend on the neutral. However, the airhandler does and it might have been damaged.
But all in all I think that something else might have happened. That there might have been a cross with a high tension line.
But the first thing is that would get the power company out to verify that that everythign up to yur service connections is good and proper.
Then you should have the electrican to check wiring at the panel and any suspected receptacles to see if there are any signs of overheated wiring.
And of course verify that each outlet is working.
> I checked the breakers, & almost half were tripped.
Were they all on the same leg? That sounds like a loss of neutral. Also, follow the wires serving your house back to the power company's transformer. Are the unaffected neighbors served by the same transformer or different ones? Likely different ones if it's a loss of neutral.
This being a well documented incident, with the fire department responding, it's clearly the POCO's insurance that should pay for all the damage. Get your electrician friend to check things out and make sure you find everything they should pay you for.
-- J.S.
Based on your description, and assuming that all the tripped breakers were on one "side" of the 240V line, everything on that "side" was exposed to potential damage.
The wiring itself would not have been damaged, unless somehow subjected to some very specific (and unlikely) overcurrent conditions, and regular switches and outlets should be OK. Similarly, any incandescent light fixtures should be OK, save for the possibility that the bulb was burned out if it was on when the problem occurred.
However, any sort of electronic device on that "leg" could have been damaged, even if it was turned off at the time (since most electronics nowadays are actually "always on" internally). This includes things like light dimmers and X-10 switches and outlets, should you by any chance have those.
Also, fluorescent fixtures that were turned on may have been damaged (damage to the ballast and also the lamps).
Your doorbell transformer and things like telephone and cable amplifiers may have been zapped.
Not much you can do to prevent this, aside from making doubly sure the ground wire from your service entrance or breaker panel is firmly connected to two or three different good grounds.
Re: "Also, fluorescent fixtures that were turned on may have been damaged (damage to the ballast and also the lamps). Your doorbell transformer and things like telephone and cable amplifiers may have been zapped."Good points. Florescent ballasts are a concern and some care is called for in their operation for some time after such an accident. If a florescent fixture shows unusual behavior, assuming it was reliable before, like having to be turned on several times to come on, dimming of the light or turning itself off and back on, usually a sign of overheating, they need turned off until they can be closely examined.It would be wise to go room to room and look for the plug-in block transformers. Check to see if each of these is working, supplying power to its parent device and also feel them to see if they are more than slightly warm. These small block transformers have been linked to some house fires. Even without being damaged by improper voltage some are so cheaply made that they lack functioning basic internal safety devices like fusing and thermal disconnects. That they could be damaged by surges only multiplies the risk.These units are, if plugged in, always on. Which means they are always vulnerable and always drawing a small, but substantial, amount of power. Some energy writers have taken to calling them vampires. More like leaches IMHO. They are slowly bleeding your wallet by way of the power bill. A pet peeve.Do contact the power company customer representative. Explain the situation. They, to avoid possible liability, may pay for an electrical contractor to come out and give your house the once over.
Bill, John, Dan, 4lorn, thanks for all the advice. We've been talking to the power company (ComEd) since this a.m., & they don't seem too concerned. They're sending out a claim form, but that's about it, so far.FWIW, several other neighbors are having the same problems as we are, so I guess I'll talk to them, & see if they got a better response from Edison. So far, we figure we've lost 2 cordless phones, an answering machine, a CO2 detector, a fax machine, & the transformer to the furnace. I realize it could have been far worse. My electrician should be out in the a.m.
(By the way, the breakers were tripped on both sides of the panel. Could a lost neutral still be responsible?)Thanks again for the help. Greg
> (By the way, the breakers were tripped on both sides of the panel. Could a lost neutral still be responsible?)
Yes. Panels usually alternate legs on each side, every other breaker. Whether it was a lost neutral at the transformer or some other reason, it's still Edison's fault and on their nickel to put things right.
4lorn1 -- We have a name for those little plug-in transformers: "Wall Warts".
-- J.S.
I prefer the term "pregnant plug" myself.
"FWIW, several other neighbors are having the same problems as we are, so I guess I'll talk to them,"If you still have 1/2 of your circuits out and other people have the same problem call the power company for a repair. Sounds like they have one leg out. "By the way, the breakers were tripped on both sides of the panel. Could a lost neutral still be responsible?)"Yes. As you go down the column they alternate between legs and likewise for the other column. But also it is hard to figure out failure modes and specially without personally seeing the evidence and making measurements.But there are failure modes that could cause breakers on either leg to trip.
On most panels, alternate breakers on one side of the panel are on alternate sides of the 240V line. If "half height" breakers are installed, though, generally each pair will be on the same "side".If not a lost neutral, then probably high voltage got crossed onto one leg.
Discuss with your electrician the possibility of adding a whole house surge protector.
A whole-house surge protector wouldn't do any good in the floating neutral case. Might help a little if the problem is a HV line crossing with a 240V leg, though. (Or might just blow up and take part of the panel with it.)