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Old 12-13-2010, 05:11 PM   #16
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Power loss


You aren't going to find much with a multimeter. Here, I'll do your testing for you: all the voltages are currently correct. The problem is that the neutral current is going to the wrong place. You won't be able to measure that without unhooking wires. Why bother? Find all of the neutral connections from the panel all the way back to the street and make sure they are all tight and not corroded.

You aren't going to get out of calling SOMEONE to do this unless you plan on climbing a power pole with a ladder, which is usually illegal. One way or another, you ARE going to call the power company, unless you are lucky enough for the problem to be inside your panel, which it quite likely is not.



I do this every day and I still don't climb poles!

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Old 12-13-2010, 09:01 PM   #17
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Originally Posted by emolatur View Post
You aren't going to find much with a multimeter. Here, I'll do your testing for you: all the voltages are currently correct. The problem is that the neutral current is going to the wrong place. You won't be able to measure that without unhooking wires. Why bother? Find all of the neutral connections from the panel all the way back to the street and make sure they are all tight and not corroded.

You aren't going to get out of calling SOMEONE to do this unless you plan on climbing a power pole with a ladder, which is usually illegal. One way or another, you ARE going to call the power company, unless you are lucky enough for the problem to be inside your panel, which it quite likely is not.



I do this every day and I still don't climb poles!
How do you know if the problem is fixed? If all the voltages are ok and there's no dimming problem (which there isn't now), what test would determine that everything is working correctly? After all, I wouldn't even know about this if the power loss hadn't occurred, but now there's no power loss.
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Old 12-13-2010, 10:22 PM   #18
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How do you know if the problem is fixed? If all the voltages are ok and there's no dimming problem (which there isn't now), what test would determine that everything is working correctly? After all, I wouldn't even know about this if the power loss hadn't occurred, but now there's no power loss.
Just because the power isn't acting up right now doesn't mean that the problem has gone away. We're talking about a mechanical connection here. Either a wire has come loose, has become degraded, or is broken. The connection is probably intermittent due to environmental factors (like a windy or rainy day).

I know this has been repeated many times, but have you called the power company yet? A lot of times, a failed neutral occurs somewhere between the transformer and the meter, which is their responsibility and there's nothing that you (or even a licensed electrician) can do about that. The PoCo should not charge you to come out and check their wiring between the pole and the meter. They do not want their transformers damaged, so they'll be pretty quick to fix any problem they find on their side.

The PoCo will come out and check the voltage at your meter *while* a high current 120V appliance is running (a nice big microwave will do the trick). Testing the voltage without a large load on one of the legs will tell you nothing. They will also physically inspect all of the mechnical connections between the pole and meter and fix whatever they find.

When my wife and I bought our house two years ago, we had been in the house for a day and a half before we started seeing the same type of problem. If we turned on the microwave, the TV would turn off, alarm clocks would reset, etc. We called the power company, who had a truck in our front yard in 30 minutes. They determined that the neutral in the underground service lateral had corroded. The repaired the lateral that day and were done in 20 minutes, and then a couple of weeks later, they came back, installed a new transformer pedestal and completely replaced the service lateral back to my meter. This didn't cost me a dime, and it fixed the problem.

If the PoCo comes out and says everything is fine on their end, then you can start rooting around in your panels and wiring, but the issue is most likely on the other side of the meter anyway, which you can't do anything about. The longer you wait to call the PoCo, the more likely you are to blow up one of your appliances (and maybe your house) because of overvoltage.
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Old 12-13-2010, 11:18 PM   #19
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The whole thing about blowing up an appliance is but part of the problem. You'll know when that's happening, and if you're smart, you'll hit the main breaker, saving SOME of your appliances, and, more importantly, your house.

My bigger worry in this case is actually the fact that the problem is "solved". All of the neutral current is being diverted elsewhere. My bet would be through the ground wire, to the water heater, through the pipes. The problem is the water heater probably has something like a 10awg ground. A sufficient load imbalance (which is to be expected on a residential service) could EASILY overheat a 10awg conductor!

How many other inadvertant routes to ground might it find? My first encounter with a bad (completely missing!) service neutral routed all the neutral current through the side of the boiler. I was called because "the furnace is throwing sparks and it isn't even on". The sheetmetal sides, the back of the handybox attached to it, and about 2 feet of wire inside the conduit were completely torched. Yes, losing half of your appliances and blowing up a bunch of light bulbs is expensive. Burning down your house is even moreso.



What do you test? Well, in addition to someone's comment about the voltages being checked at the meter while a large appliance is running, I would expect "alternate paths" to be removed.

I DON'T test. I solve the neutral problem while the symptoms exist, and the problem is fixed when the symptoms go away. I don't mask them. If neutral current burned up a bunch of splices enroute to a water heater, for example, I'd turn off the power to that water heater and LEAVE THE SPLICES DISCONNECTED until AFTER the neutral problem is corrected.

In this particular case, I suppose you could get satisfactory results by disconnecting that water heater. This should cause the problem to re-surface. This is a case where you really should have a professional involved. What if the original problem has gotten even worse while you've been ignoring it due to it being masked? When you disconnect that water heater, you will be removing the "alternate path" that the neutral current has been using. You may essentially have no neutral. Yes, at that point, you will be able to prove something with a multimeter, but I strongly encourage you to disconnect anything of value before you begin!
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Old 12-13-2010, 11:32 PM   #20
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Okay I've thought about it a bit, here's what I'd suggest, since you're determined not to call an electrician. I'll warn you ahead of time, however, if you blow something up I'm not going to feel bad in the slightest - and you WILL still need to call the power company.

First walk around your house and unplug EVERYTHING. Turn off all hardwired lights. If you have any hardwired appliances, turn off their breakers.

Turn off the main breaker and then disconnect that water heater. Completely. All 3 or 4 conductors. Disconnect the wires and put wirenuts on the ends of them (one per wire). The main breaker has to be OFF for this, because, remember, all your neutral current is going through the water heater cable right now. Even if the water heater circuit is turned off, there's still current going through this cable. This is what we're aiming to fix. You can turn the main back on after the water heater is disconnected. At this point, anything you forgot to unplug or turn off in the first step probably just became a repair bill, since your house has no reliable neutral.

NOW plug in ONE lamp and turn it on.

Plug an electric space heater or other high-power appliance into the same circuit. When you turn it on, that lamp is probably going to get a LOT dimmer.

Your goal is to clean/tighten neutral connections, starting at the panel and working backward, until the amount of brightness change when you turn the heater on/off is minimized. (Actually, I start with the connection that looks the most likely, but whatever).



The big problem with doing this yourself is: YOU CAN'T. In your typical residential electric service, there is ONE neutral connection you can muck around with without needing someone's help: the one in your panel. That's it. The next one from that is inside the meter base, and the power company needs to be called out to pull the meter for you to legally do that. In some areas of the country, a licensed electrician (or at least someone the local poco employee knows) can usually get away with pulling a meter for testing, but the power company WILL know, and unless you know for sure that you're in one of those areas and can do this, DON'T, or it will surely become a legal/billing nightmare.

Do you really want to do all this work to test one connection when there's a minimum of four that are more likely points of failure anyway? The power company is directly responsible for two of those other connections and must (legally) become involved in order for you to even test the other two. Since there's a good chance it's their problem anyway, AND they aren't going to charge you if so, wouldn't it make more sense to just call them out and let them do their job?
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Old 12-14-2010, 12:11 AM   #21
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Originally Posted by emolatur View Post
Okay I've thought about it a bit, here's what I'd suggest, since you're determined not to call an electrician. I'll warn you ahead of time, however, if you blow something up I'm not going to feel bad in the slightest - and you WILL still need to call the power company.

First walk around your house and unplug EVERYTHING. Turn off all hardwired lights. If you have any hardwired appliances, turn off their breakers.

Turn off the main breaker and then disconnect that water heater. Completely. All 3 or 4 conductors. Disconnect the wires and put wirenuts on the ends of them (one per wire). The main breaker has to be OFF for this, because, remember, all your neutral current is going through the water heater cable right now. Even if the water heater circuit is turned off, there's still current going through this cable. This is what we're aiming to fix. You can turn the main back on after the water heater is disconnected. At this point, anything you forgot to unplug or turn off in the first step probably just became a repair bill, since your house has no reliable neutral.

NOW plug in ONE lamp and turn it on.

Plug an electric space heater or other high-power appliance into the same circuit. When you turn it on, that lamp is probably going to get a LOT dimmer.

Your goal is to clean/tighten neutral connections, starting at the panel and working backward, until the amount of brightness change when you turn the heater on/off is minimized. (Actually, I start with the connection that looks the most likely, but whatever).



The big problem with doing this yourself is: YOU CAN'T. In your typical residential electric service, there is ONE neutral connection you can muck around with without needing someone's help: the one in your panel. That's it. The next one from that is inside the meter base, and the power company needs to be called out to pull the meter for you to legally do that. In some areas of the country, a licensed electrician (or at least someone the local poco employee knows) can usually get away with pulling a meter for testing, but the power company WILL know, and unless you know for sure that you're in one of those areas and can do this, DON'T, or it will surely become a legal/billing nightmare.

Do you really want to do all this work to test one connection when there's a minimum of four that are more likely points of failure anyway? The power company is directly responsible for two of those other connections and must (legally) become involved in order for you to even test the other two. Since there's a good chance it's their problem anyway, AND they aren't going to charge you if so, wouldn't it make more sense to just call them out and let them do their job?
Thanks for all the replies. I'm convinced I need to call the poco, and will do that tomorrow or day after. I'll be here when they come and ask questions, etc, and will update before I try anything myself. Again, thanks.
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Old 12-14-2010, 01:19 PM   #22
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np. I just caught that you're in a mobile home, which adds two more connections and an outside disconnect, which has a good chance of needing replacement. The poco will tell you that. If that's the case, then, unlike many others here, I DO support that as an eligible task for a suitably-skilled DIY, so if that turns out to be the case, I'm certainly willing to assist there. (Don't let yourself think that means it's easy though. It's a PITA.)
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Old 12-14-2010, 03:02 PM   #23
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np. I just caught that you're in a mobile home, which adds two more connections and an outside disconnect, which has a good chance of needing replacement. The poco will tell you that. If that's the case, then, unlike many others here, I DO support that as an eligible task for a suitably-skilled DIY, so if that turns out to be the case, I'm certainly willing to assist there. (Don't let yourself think that means it's easy though. It's a PITA.)
Wow. You guys were right. I called the poco and timed them, he was here in 15 minutes!

He said there's no problem on the poco side. So I'm not sure how to proceed, but would like to take a shot myself.
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Old 12-14-2010, 03:47 PM   #24
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Remove all loads (unplug what you can, turn off what you can't), turn off outside disconnect, unhook water heater.

For all neutral connections from outside disconnect all the way to the main panel: loosen screw, remove conductor, tighten screw then re-loosen it, (goal is to clean out the threads), clean off any corrosion. If aluminum wire (likely), apply noalox or similar anti-oxidizing chemical. Reinsert conductor, tighten screw to torque spec written on label somewhere in the box.

Turn outside disconnect back on, verify that the problem has gone away. Assuming it has, you're done, reconnect water heater and enjoy a beer.
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Old 12-14-2010, 03:50 PM   #25
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Note that, even with the outside disconnect turned off, the meter side of it is still live. Take extreme precautions to ensure that neither unhooked neutral wires, nor tools, nor you come in contact with either of the hot conductors. The overcurrent protection on that side is either 1,000 amps or nonexistant (depending on who you ask), and the result of a short there will be a nice hot shower - in molten metal, which is slightly in excess of any temperature any human being stands a chance of surviving without hospitalization.
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Old 12-14-2010, 03:51 PM   #26
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And again, let me reiterate, there is nothing to test. You could use a voltmeter to verify that the problem is gone, but you'd still need a load to do so - and you can get the same effect by seeing how much the lights dim when you turn stuff on/off. In this case, the symptom IS your test.
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Old 12-14-2010, 06:21 PM   #27
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The neutral functions a return path to the PoCo for "used" electricity. You have two incoming hot legs with a combined potential for 240V, with one neutral leg returning. The potential for return on either of the hot legs through the neutral is 120V. When the neutral fails, the returning current from one of the hot legs will attempt to divert through the electrical ground, but if the ground cannot sustain that amount of current, the current can attempt to return via the remaining hot leg, causing an imbalance in the voltage of the two hot legs. This results in the dimming/brightening effect you have described. The dimming/brightening effect will most likely occur when a high-current 120V appliance (microwave, vacuum cleaner, power tool, etc.) is turned on and the high amount of current cannot successful return through the neutral.
Your whole write-up is incorrect.
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Old 12-14-2010, 07:37 PM   #28
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It's worded poorly... VERY poorly, so bad as to be confusing, but what he's trying to get at is valid.

If the neutral is loose or disconnected, most likely the return current will find a way through the ground wire (through metallic water pipes underground and back through the neighbors' neutral conductor is a common route) instead. If the resistance of this path is also high, some of the current from the heavier-loaded side will go through the loads on the lighter-loaded side and to the other hot conductor.

I'm sure his post confused the op but it's not altogether wrong.
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Old 12-14-2010, 08:10 PM   #29
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It's worded poorly... VERY poorly, so bad as to be confusing, but what he's trying to get at is valid.

If the neutral is loose or disconnected, most likely the return current will find a way through the ground wire (through metallic water pipes underground and back through the neighbors' neutral conductor is a common route) instead. If the resistance of this path is also high, some of the current from the heavier-loaded side will go through the loads on the lighter-loaded side and to the other hot conductor.

I'm sure his post confused the op but it's not altogether wrong.
As to clashley's post, I asked the poco guy to explain what he was doing, and he said he checked the two hot wires to see if there was a voltage difference (such as 114 on one and 130 on another, for example) and in order to do that he had me turn on a high voltage appliance (used a 1200W space heater). This seems to be what clashley was saying.
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Old 12-16-2010, 09:35 PM   #30
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Remove all loads (unplug what you can, turn off what you can't), turn off outside disconnect, unhook water heater.

For all neutral connections from outside disconnect all the way to the main panel: loosen screw, remove conductor, tighten screw then re-loosen it, (goal is to clean out the threads), clean off any corrosion. If aluminum wire (likely), apply noalox or similar anti-oxidizing chemical. Reinsert conductor, tighten screw to torque spec written on label somewhere in the box.

Turn outside disconnect back on, verify that the problem has gone away. Assuming it has, you're done, reconnect water heater and enjoy a beer.
I disconnected WH, unplugged everything and opened all breakers. There are 2 main neutral wires at my inside box, both under the same set screw. I took them out and saw no corrosion on them or the connection. There is one main neutral from the outside box into the conduit that goes to the inside box. Problem is it's under a very large allen screw and I don't have a wrench big enough. There seems to be some corrosion but it may be a while before I can get it loose.

With the WH disconnected but all circuits back on I found that where I have a heavy duty extension cord that leads to my computer and a lamp, if I unplug that cord, I get very erratic power - some light bulbs dim almost completely out, the fridge stops, the AC stops. When I plug it back in, the power seems to be more evenly distributed, but with the WH disconnected, I still get a large power drop when I run a large appliance. Then, when I reconnect the WH, everything is fine. Any suggestions?

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