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Piedmont 11-08-2007 03:36 PM

200 amp service, someone explain what may have happened?
Seeing the other 240v post, maybe someone can explain what happened to my house. Just 1 month within moving in I had lights periodically going dim, or extremely bright on occasion. I don't mind them going dim, but having a 65 watt light go to the brightness of about a 100 watt light then back scares me. Called in an electrician, who looked at my current 200 amp service said I'm not touching that first thing is a new service.

I got electrician #2 who does services and my old panel wasn't made for decades, was rare brand, main breaker lever was broken off, the breakers were dripping with water and he told me he can't be sure with all the water in them that they will trip when they're supposed to. We also could not find new main breaker for that panel (not even used one on e-bay) so decided replace whole thing. He replaced everything from the connection & wires at my roof, new wire to meter, new meter, new wire to panel, and all new breakers.

Afterward my lights going bright & dim still occurred. I brought him back, he went up to the pole and measured the lines coming into the house and said something like two of the wires are supposed to measure the same but they aren't (I have 200 amp service) and told me the electric company has to be called. I called electric company they were there within an hour said oh my god. Then, replaced my wires from the roof to the telephone pole and I've not had a problem since.

Now that I understand some, anyone want to take a stab at explaining what was likely happening?

goose134 11-08-2007 04:40 PM

When you say the electrician said that two wires didn't measure the same, what were you referring to? Voltage? Size? Amperage?

Stubbie 11-08-2007 06:05 PM

Most likely you had an issue with the neutral in your overhead drop maybe about to break or something. In a triplex overhead drop the neutral is bare and it looks like wire rope ( called a messenger cable). This bare cable *neutral* regulates the voltage on the two hot wires by referencing them to earth via the center tap of the pole transformer keeping the voltage on each at around 120 volts. If that bare neutral in the drop corrodes, has a loose connection at the xformer or drip loop crimps or the strands break leaving in essence a much smaller wire the impedance increases on the return current and the voltage on both legs begins to float above and below 120 volts as the earth reference (120 volts) of the electrical system is beginning to be lost. High voltage (bright lights) then low voltage (dim light) this continues until the neutral opens entirely then you have bursting light bulbs and destroyed televisions etc... due to the high voltage created by the system not having a earthed reference back to the transformer. Many times this intermittent brightening and dimming occurs on windy days for the most part as the swaying of the overhead drop will aggravate any loose you have neutral now you don't. The whole house is affected as the service neutral is common to the entire supply to the home.

If this occurs on a neutral of a 240 volt multiwire branch circuit serving 120 volt loads then only the branch circuit is affected as below

Hope this helps


frenchelectrican 11-08-2007 07:26 PM

Stubbie :

I did see one case i was working on one commercal location which it have 600 amp overhead cable run from one building to other building and one of the connections on the netual line went bad on the cinqplex overhead cable [ basically the same as reg redental cable but much bigger in sizewise]

and the netural connector got funkey and got it pretty hot the point where it is dark outside if you look at it right you actally see it glowing red hot !!

that how hot the connector was and they called me the first thing i did spot i say shut off the power now and i went back to my shop and get the big diesel genny to run the power during the repairs it was pretty good mess there.

it the same idea with resdental area too with ACSR cable when the alum strands break off only steel strand still holding up the OH drop and you can see how much current it can run thru and it will build up heat fast too.

Merci, Marc

Stubbie 11-08-2007 08:10 PM

Oh Yeah....been there let me tell you. Had an office type come in one night and wanted to know if any of us in the shop would be interested to now that something was glowing red coming into the building. Sorta looked at him like he was jerkin us around. Bout that same time one of the maintenance guys came in like :eek: :help:. At that we climbed on the taylor cart and got out there let me tell ya. It was the neutral messenger at the weathermast drip loop connection to our pump house and you didn't have to look right to see how hot it was. The insulation on the ungrounded legs was a smokin big time...whew... that was a close one. Would have been a phase to neutral short pretty soon. Turned out that a hi-lo hit the overhead the evening before and jerked the wedge clear off the messenger. Hi-lo Driver was to worried about losing his license so sneaked away. Damn hi-lo drivers....:)

Andy in ATL 11-08-2007 08:56 PM

It's always a "Thank God it's not my FRIKKIN neutral" moment for me.:laughing: ALWAYS better when it is the POCOs fault!

Piedmont 11-09-2007 08:13 AM

Thanks! I actually understand! After understanding he more than likely told me what he measured was supposed to stay the same (not be the same as I originally posted). He was probably watching the voltage cycle up and down when it should've been a constant 120v, now that I understand. :) Glad I got that fixed after hearing what will eventually happen if I didn't!

jogr 11-09-2007 10:29 AM


Did you ever find the source of the water that was getting in your panel and get that fixed?

Piedmont 11-09-2007 11:25 AM

Yes. At first he thought it was the rusty meter, and water was going inside the meter then getting inside the cable which ran to my panel. My panel is in a bad location it's connected directly underneath the meter, below ground in my basement, no room for a drip loop. After he was done putting in the service water was still running down my panel when it rained.

I called him back, he just couldn't believe it was still happening. He then made sure it was especially sealed up. Still happened next rain. He said, it's impossible it's the work he did and then tried to find other causes and found the phone line goes into my house over the panel and dips touching wires that go into the panel. That must be the culprit and he sealed up the phone stuff. No more water.

I felt bad for him, he explained to me what was the true cause and wasn't anything to do with what he did but still nonetheless he is one that really takes problems to heart even if it had nothing to do with him. He's a guy with his own business trying to support his family (his wife stays home raising the children and does the billing for him) and he's trying to make his business start. My father the same way (carpenter). I understood completely, he explained the service was still needed since the main breaker had no lever (who knows if it would even trip) and I sleep at night knowing I have a new service but the electrician left beating himself up running it through his mind a billion times that the service didn't fix my electrical problem and didn't fix the water coming in, and in the back of his mind wondered if I felt the service was necessary... as I've seen my father do countless times (for different situations). So, I felt bad for him cause he did a phenominal job. When I remodel my kitchen he'll be doing the electricals.

Ended up being leaky telephone wire penetration, water followed the phone line in, and from there diverted to other wires that went into my main panel.

Billy Bear 12-11-2007 11:01 PM

can anyone tell me why the ground did not pick up the earth ground for the netural i think they are bonded at service entrance. thanks just wondering

Speedy Petey 12-12-2007 06:11 AM


Originally Posted by Billy Bear (Post 79981)
can anyone tell me why the ground did not pick up the earth ground for the netural i think they are bonded at service entrance. thanks just wondering

This is very confusing question but I'll try.
The reason is because that is not the "ground's" job. The earth does NOT provide or make a neutral OR a ground. At least in the sense of carrying regular OR fault current.
If you loose a neutral and all you have left are your grounding electrodes all you are doing is dumping current into the ground. The earth does NOT conduct very well.

Piedmont 12-12-2007 03:50 PM

That's exactly the reason that's been beat into my head lately.

Grounding rods can't dispense of a lot of juice. Think of the typical circuit with a power, switch, wire and light bulb. Flicking the switch the bulb should turn on and shine nice and bright. Now, remove a small piece of wire and replace it with earth... now flick the switch on/off it'll be pretty obvious earth is no replacement. Sure some current should flow through it, maybe you'll be lucky and have the bulb somewhat lit but it ain't a neutral/ground wire connection back to the power. But, does follow the same principle that with grounding rods in moist earth will be more effective than those in dry. And, pretty much a grounding rod in dry earth may even be useless. I believe the grounding rod need be long enough to be driven in moist earth but don't quote me on that and, hope that helps explain why one can't depend on the earth... although it can't dispense of much current, what it can take may just be enough that saves ones life or property.

Andy in ATL 12-12-2007 04:22 PM

Groundrods are worthless.:laughing: :wink:


Stubbie 12-12-2007 05:39 PM


Your making a critical error in your analogy. Grounding rods can put hundreds of amps or more into the ground if you have enough voltage pushing those amps. The grounding electrode system for a dwellings electrical system was never intended to be equated with ordinary residential voltage levels of 120/240 volts. Low voltage is considered around 600 volts or less. Lightning is easily 25,000 volts DC or much more... simply apply this to ohms law and you will see how earth conducts current by varying your resistance levels and voltage levels. Also remember that neutral current has little or no voltage pushing it. Grounding rods can dispense many hundreds of amps and this depends on how deep they are in the earth, the deeper the less resistance. NEC only requires 8 feet... it will be rare you will have 25 ohms or lower with a rod that shallow but that is what we put them at to satisfy the nec. Remember it is a minimum requirement to be supplemental to the water pipe which is connected to every water pipe under the ground so it essentially is one giant electrode based on the surface area in contact with the earth. Rods are not the best electrode ... rebar in the concrete foundation is much better. Not every one has rebar (ufer) grounding so rods are the most common supplemental electrode. They are far from worthless. Btw when you drive a ground rod make freakin sure your underground lines have been located if you penetrate a service lateral your going to find out how good of a conductor they are...:)

joed 12-12-2007 05:55 PM

If all your water lines, the city's water lines and your neighbour's water lines are metal the ground bond to the plumbing can act as a neutral feeding the current back through your neighbours neutral wire and you probably never know it.

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