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Last year our lights began surging and then my wife noticed the old fuse holder was broken and not making a good contact. We decided to upgrade the fuse panel and bring it closer to code. The first person hired was "doing it on the side" and got the panel installed but when the 4th breaker was turned on it created a helluva light show. Apparently 1 side was pushing 230 v while the other only 60 v. So now with only 2 rooms on 2 different breakers if we try to run any appliances at all the lights surge. I tried to simply test the voltage on the breaker and as soon as I put the black lead on the neutral bar every bulb on that circuit blew. As the owners we are allowed to do repairs as long as we hire someone to tie into power, or something like that. What I'm asking is why or how could a simple multi meter cause lights to blow by simply testing the breaker? Also, the breaker never did trip, just blew the lights. Thanks

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    Hello, and welcome to Home Improvement. Step 1: throw your main breaker. Step 2: don't turn it back on until you are sure this is fixed. Step 3: continue to live. – Daniel Griscom Feb 28 at 11:47
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    I agree with the answers/ comments below stating call the power company because of 5he imbalance , with that said since you tried to put a black or hot to the neutral you should seek professional assistance, this is a DIY site but that is a dangerous move in the US. – Ed Beal Feb 28 at 12:44
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Contact your power company Right Now and report an outage

It'll be fixed for free in 2 hours.

You actually have a power outage. Your house is partially working because electricity is delivered in 3 wires. When one wire fails, there's a 2/3 chance of having your 240V circuits go out along with half your 120V circuits (unless you turn on a 240V appliance, then weird things happen).

However there's a 1/3 chance of the 240V appliances continuing to work, but the two banks of 120V appliances drifting significantly off 120V. One goes higher than 120V, and the other one goes lower by equal amount. They still add up to 240V, but one appliance is getting 190V while the other one is getting 50V. And worse, it changes as you turn loads on and off. This is called a lost neutral. The neutral's job is to clamp voltage at 120V.

This last mode is the most dangerous and the most difficult to detect. This is usually on the power company's end. Given that you just replaced everything on this end, I'd say 99% in this case. The power company fixes this for free.

  • Any safe way to test for this? It sounds like just using the multimeter blew a bunch of bulbs... or is that the right idea but turn off breakers first? LED & CF bulbs might not surge (brighten & dim?) like an incandescent, so it might be hard to even notice a problem – Xen2050 Feb 28 at 13:33
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    @Xen2050 It helps if the multimeter isn't on "amps" and isn't a piece of junk. There is no way a multimeter used properly would blow anything. Also correlation is not causation. – Harper - Reinstate Monica Feb 28 at 13:42
  • That's what I suspected... a decent meter should have a fuse too that should've blown first. – Xen2050 Feb 28 at 14:55
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Looks like lost neutral: call your utility company and report them the dangerous condition, they'll fix it fast.

PS: the 'electrician' that replaced your old fusebox wasn't too good at his job as he never checked that potential risk (he could have solved just phoning the utility to do so): if you run appliances only on one leg the 'circuit' will be interrupted and all your metallic 'grounded' stuff will became live

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