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Old 12-04-2011, 08:45 PM   #31
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Help! Glowing spot at bonding screw


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Originally Posted by jimmy21 View Post
I think that screw is what bonds the neutral bar to the neutral service conductor and its making a crap connection causing it to heat up. Take that screw out and wire brush it, apply some de-ox and torque it back down.
Too late, it's welded in.

For other matters, I found 2 voltmeters fairly easily, but the digital meter I didn't find the leads. I have an older analog meter that has the leads, so in the dark it's hard to get a precise reading, but here's what I found.

I measured hot-to-hot and got 240 volts.
I measured hot #1 to neutral and got 140 volts
I measured hot #2 to neutral and got 110 volts

I got the same readings with some circuits on so I could see as I got with all circuits off.

Again, these aren't highly precise readings, but there's clearly a difference in voltages at the hots whether load is present or not.

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Old 12-04-2011, 09:06 PM   #32
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Help! Glowing spot at bonding screw


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Originally Posted by jimmy21 View Post
I think that screw is what bonds the neutral bar to the neutral service conductor and its making a crap connection causing it to heat up. Take that screw out and wire brush it, apply some de-ox and torque it back down.

Nevermind. Looks like that screw bonds the can. There shouldn't be any current on it, but either way, the heat is from a poor connection
Correct, the screw bonds the enclosure to the neutral. The neutral connection should be made on the buss to the neutral conductor.
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Old 12-04-2011, 09:07 PM   #33
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Help! Glowing spot at bonding screw


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Again, these aren't highly precise readings, but there's clearly a difference in voltages at the hots whether load is present or not.
You're getting a voltage divider effect from different loads on each leg and a bad return path. I would just call the PoCo right now, and tell them your electrician diagnosed a floating neutral.

If he still comes tomorrow and says the same thing, you've gained some time (only maybe since it's a Sunday night). If he finds something else, no harm done.

The circumstantial issues with things happening after the storm further the case for a floating neutral.

Personally, I would power down the house completely (this might bolster your case with the PoCo). The arcing is very concerning.
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Old 12-04-2011, 09:07 PM   #34
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Help! Glowing spot at bonding screw


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Originally Posted by WillK View Post
Too late, it's welded in.

For other matters, I found 2 voltmeters fairly easily, but the digital meter I didn't find the leads. I have an older analog meter that has the leads, so in the dark it's hard to get a precise reading, but here's what I found.

I measured hot-to-hot and got 240 volts.
I measured hot #1 to neutral and got 140 volts
I measured hot #2 to neutral and got 110 volts

I got the same readings with some circuits on so I could see as I got with all circuits off.

Again, these aren't highly precise readings, but there's clearly a difference in voltages at the hots whether load is present or not.
The voltage difference between the leg is signs of a loose neutral.
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Old 12-04-2011, 09:22 PM   #35
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Help! Glowing spot at bonding screw


I went to my neighbor's house and checked, and his voltages were the same on both legs, but I wasn't going to power down his house.

I borrowed a flashlight (we gave up on flashlights because every time we have one, the kids find them and use up the batteries or otherwise destroy them) and this time I found that with the main shut off that both legs are measuring 120-125.

I installed a jumper from the LH ground bar to the neutral bar (#4 solid copper) and now both legs read 120-125 and the arcing stopped.

So I won't cancel any appointments, it sounds like something still isn't quite right. At least I can feel safer leaving the alarm clock on, but I'll be up a bit longer so if anyone feels different I'd like to hear.
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Old 12-04-2011, 09:33 PM   #36
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Help! Glowing spot at bonding screw


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Originally Posted by WillK View Post
I went to my neighbor's house and checked, and his voltages were the same on both legs, but I wasn't going to power down his house.

I borrowed a flashlight (we gave up on flashlights because every time we have one, the kids find them and use up the batteries or otherwise destroy them) and this time I found that with the main shut off that both legs are measuring 120-125.

I installed a jumper from the LH ground bar to the neutral bar (#4 solid copper) and now both legs read 120-125 and the arcing stopped.

So I won't cancel any appointments, it sounds like something still isn't quite right. At least I can feel safer leaving the alarm clock on, but I'll be up a bit longer so if anyone feels different I'd like to hear.
I think that neutral bar wasn't making a connection and the neutral current on that buss bar was trying to go through the enclosure. Or perhaps there was supposed to be a jumper from the original installation and it wasn't installed.

You should probably bond your enclosure with a new lug or something, since the factory one is now useless
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Old 12-04-2011, 09:51 PM   #37
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Help! Glowing spot at bonding screw


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...I installed a jumper from the LH ground bar to the neutral bar (#4 solid copper) and now both legs read 120-125 and the arcing stopped.....
Yup, that's the short-term fix for the moment. At least, your box won't do a melt-down overnight.

Since this is your main service panel, I'd leave that in place in lieu of the bonding screw, which is toast at this point. #4 is the proper size for a 200 Amp service.

When your electrician shows up tomorrow, he should be able to figure out why your neutral has failed. It could be a bad or broken connection outside, as a result of the recent tree incidents. Or some other bad connection on the pole or transformer.
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Old 12-04-2011, 09:59 PM   #38
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Help! Glowing spot at bonding screw


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Reason I asked earlier was to clarify that the event is still occurring. Kb sparky is likely correct in his analysis.....
Thanks for the compliment. Hey welcome back! Have not seen you around here for MONTHS!

How have you been?
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Old 12-04-2011, 10:05 PM   #39
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Help! Glowing spot at bonding screw


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The voltage difference between the leg is signs of a loose neutral.
Yup. All signs so far point to this. The up and down (L-N) voltage readings confirm it.
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Old 12-04-2011, 11:35 PM   #40
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Help! Glowing spot at bonding screw


Wilk.,

I am not sure if I did catch someone mention the bonding on the water line but if that the case if you are on the métro { city } waterline then there is one more step you will have to do this but senice you will have your electrician to come out and assit you on the loose netural connection situatuion.

For the water pipe bonding what I useally do is take a ampclamp and read the current drawage { there is a serious warning JAMAIS (NEVER) remove or loosen the bonding clamp for safety reason }

Some case with bad netural connection you will get current reading thru the water pipe { only if you have metal water pipe run underground that will useally do this but plastique it will do squat }

By the way do you have electrique water heater ?? if so it may have bad heating element going out. ( this generally pretty common on hard water situation )

Few guys in this fourm did give you the best answer there.

Merci,
Marc
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Old 12-04-2011, 11:57 PM   #41
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Help! Glowing spot at bonding screw


Thanks to all.

Regarding the water heater and water pipes, that was a point I had adressed to satisfy concerns raised by the inspector on the permit... I had assumed that it was bonded, but apparently I needed to redo it plus the code when it was bonded previously only needed it to be bonded one place. So I have a single wire clamped to the water pipe at both sides of the meter then both sides of the water heater and then to the gas pipe.

The meter isn't metal. The water heater is gas. The pipe coming from the city water main is copper. The house is plumbed mostly with copper, except an icemaker line I did in CPVC.
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Old 12-05-2011, 02:27 AM   #42
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Help! Glowing spot at bonding screw


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Originally Posted by kbsparky View Post
Yup, that's the short-term fix for the moment. At least, your box won't do a melt-down overnight.

Since this is your main service panel, I'd leave that in place in lieu of the bonding screw, which is toast at this point. #4 is the proper size for a 200 Amp service.

When your electrician shows up tomorrow, he should be able to figure out why your neutral has failed. It could be a bad or broken connection outside, as a result of the recent tree incidents. Or some other bad connection on the pole or transformer.
I'm betting the service neutral has degraded from broken stranding. The only thing I have seen similar to this was a situation years ago where a home lost one leg of the service. That turned out to be a broken and corroded connection at the drip loop from a split bolt connection. The next door neighbor said she had brightening lights and dimmings lights all the time. I took a look see and the bonding screw it was bright red as was the neutral bus for about an inch. I followed the triplex out to the pole and could tell that several of the strands were broken on the service neutral (messenger) and only one or two remained intact just before the center tap of the transformer. POCO sent a bucket truck and repaired it a few hours later. I've never seen the arcing before though and I was starting to think that the bond screw in this example was not tight and the current using it was jumping the air gap between the screw head and the neutral bar.

To answer your other question ... I've been fine and life is good. Thought I would check in and see how all you guys have been doing these past months.
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Old 12-05-2011, 07:07 AM   #43
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Help! Glowing spot at bonding screw


Running a jumper from the neutral bar to the panel metal itself is a suitable permanent substitute for the ground screw that digs into the panel back and which, here, is welded in a position that does not make good contact. Main breaker off when doing this.

When it keeps arcing from continuous power usage it can get mighty hot, enough to make nearby metal strips red hot. The panel back, being a larger piece of metal, might not get quite as hot but still hot enough to burn your fingers.

If you keep load to a minimum (possibly leaving the refrigerator plugged in but definitely not using stove or oven or dryer) you might get by with a bad neutral and with the ground acting as neutral for a short time until the power company can come out and fix it.
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Old 12-05-2011, 07:19 AM   #44
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Help! Glowing spot at bonding screw


Running a jumper from the neutral bar to the panel metal itself is a suitable permanent substitute for the ground screw that digs into the panel back and which, here, is welded in a position that does not make good contact.

If you keep load to a minimum (possibly leaving the refrigerator plugged in but definitely turning off electric water heater and not using stove or oven or dryer incl. hair dryer) you might get by with a bad neutral and with the ground acting as neutral for a short time until the power company can come out and fix it.
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Old 12-05-2011, 07:35 AM   #45
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Help! Glowing spot at bonding screw


you can just move the neutral wire on the right neutral bus and put it at the left one and completely remove right neutral bus as it is defective now. This has nothing to do with ground, it was just a loose bus connection

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