I thought I’d start this new thread with all the new info.
This morning I read 6.5 to as high as 9.5 volts from the cable shielding to the ground wire that is attached to the water pipe. It fluctuated. I next went into the main elec panel and measured the voltage from each lug of the main breaker to the neutral. On one leg I got 132v and the other was around 112 to 115 and fluctuating. It got as low as 109v on that same leg. Perplexed by such differential I suspected a transformer issue. To rule it out I then turned off the main breaker and all branch circuits. I read the voltage between the two entrance conductors and read between 121 and 122 v on each leg. That ruled out a transformer issue and told me that the problem was clearly within the circuits of the house itself.
Here is where it gets interesting. I next began to turn on one breaker at a time and measured voltage between each main lug to the neutral. I wanted to find out which breaker(s) caused the variance. With each breaker conming on I stayed around 120 to 123v between each main lug to neutral reading. BUT….I found one breaker that shot me up to 125 to 128v. I turned that one back off and proceeded to continue to check breakers to see if there was more than one culprit. There was, I found a total of 3 breakers (Homeline series) that caused one leg of the main lug and neutral to read at 125 to 128v and a lower volt reading on the other main lug. I turned all 3 of those breakers off and reconfirmed that I was getting a good consistent 121v between both main lugs with all the other breakers on.
It gets more interesting. I’ve identified one ckt in particular, a SP 15A that guarantees a spike in voltage on the one leg to at least 133v while at one point dropping the voltage in the other leg to 109v. What is on that ckt is 3 window AC units, one of which is plugged into a power strip and the others direct into wall outlets.
The one window unit, when I turn the breaker on I can hear the AC unit come on. It starts out fine, but a few secodns later you hear something kick on inside it, I assume the compressor and when it does come on the lights on that ckt noticably dim and you hear a really low electrical hum sound inside the unit while it’s dimming the lights. It doens’t sound like a normal hum of an AC unit. It sorta sounds like one of those Tesla coil arcs or whatever they’re called that you see in Frankenstein movies of old. At the same time this happens I get a spike on the one leg up to 133v and stays current around 128v. while the other leg measures 115 to 117v. When the compressor goes off I get a voltage reading of 123 to 125v on the one leg and about 118 on the other. So it seems this window unit has some sort of problem developing. Additoinally, when I’d run this unit the compressor would come on for a few seconds, dim the lights, spike my voltage reading and 5 secodns later it’d turn off again (the compressor, not the whole unit), my voltage would drop and lights would brighten back up, adn then a few secodns later again it’d try to come back on and do the same thing. Like it wants to come on but cant’ but after cycling a few times it finally does.
To find out if it was one particular window unit I shut all 3 off and started off clean. I turned one on which caused a spike to 128v and settled down to around 125v. I turned that one off and turned on another. Same thing. I turned that off and turned on the problematic one and got my 133v spike and lights dimming. I then turned all 3 on and am reading between 128v to 133v on one leg and 112v to 117v on the other leg.
THis 15A ckt runs everywhere and happens to be the one wire I felt last week that was quite warm. I put a clamp meter on it and read 7amps with all 3 running. However, not all the compressors were running , just the fans, thus the reason for the lower amp reading. I suspect the ckt is running dang well near 15a when all 3 are running full blast. This ckt also appears to be junctioned in multiple places as well.
To add further confusion to this, assuming these window units are dumping current onto the ground wire or neutral, then how did the current get to the cold water pipe only to go thru the cable ground wire and then fry the coax when the elec panel was not bonded to the cold water pipe, something I remedied last week by bonding it properly. This happened 2x before I bonded the elec panel to the water pipe.
Any further thoughts on what I can check? I never saw this before, voltage variance between legs. Would a loose neutral still do that?
If at first you don’t succeed, try using a hammer next time…everything needs some extra persuasion from time to time. -ME
Edited 7/29/2008 1:53 pm ET by WillieWonka
Replies
I had a similar situation in my house some years ago. Every so often, if I turned on certain lights or appliances everything else in the house on the same side of the breaker panel would quit. If I went to the panel and turned the main breaker off then back on again, everything would be fine again for another couple weeks.
It took several calls to the local utility (who initially claimed it wasn't a problem on their side) but eventually they figured out there was a bad connection on one of the hot wires at their transformer out on the pole. They repaired it, and everything's been fine since.
I once found a similar situation in my sister's house, except in that case it was a loose connection where the service wires came into her breaker panel - it was so bad, the insulation on the wires was starting to melt. I called the power company (on Christmas day, no less; we were there for Christmas dinner and I was wondering why all the lights dimmed when her furnace came on), and they came out and temporarily killed power at the pole while I cleaned up and tightened the connections inside the panel.
You have a bad neutral connection, plain and simple.
It can be anyplace from the panel, through, the meter, connections, the connection at the weather head, the connects on the drop at the pole and the connects at the pole to the transformer neutral.
And many of those connections are the POCO's.
The resitance is high, maybe 0.5 ohms or so.
You have to have a much larger load on one leg than the other and right now that is the AC's.
Most likely what is happening on the AC is that voltage drops enough that the motor overheats and they have internal, self reseting thrermal overload.
My guess is that hair dryer was on one of the circuits with an AC unit.
Now my this was affecting the cable BEFORE you bonded the panel the water line there are two possibilities.
1. You have 2 separate unrelated problems.
2. You have some "hidden" connections.
Ones that I can possibility think of is a that there;
A bootleg receptacle (no ground wire and the ground terminal connected to the netural) that feeds the cable box or some piece of equipment that is grounded to the cable box via the interconnect cables.
EDIT - it does not have to be a bootleg receptacle. With the neutral bonded the egc at the panel it will have the same affect if you have a band neutral. And even with a "good" ground electrode the resistance is often high enough that it won't carry much of the current.
A ground wire that was added to the nearest cold water pipe to ground an ungrounded receptacle and later that ground wire was ended up also being connected to other grounds that go back to the panel where they are bonded to the neutral.
There is a cable that has worn through and in contact with a water pipe.
It has an electric water heater and grounded through that. Possibly through other appliacnes.
There is an unknow connection to the water pipe, possibly on the outside underground.
From your description I gather that this is an old house and thus a good possibility of having many changes over the years and any of these could have happened.
This isn't the house with the circuit with the ground problem that you had a couple of eyars ago is it.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Edited 7/29/2008 4:58 pm by BillHartmann
Bill, stop it, yoiu're supposed to be making this easier on me, not more complicated. LOLNot sure which house you're referring to that I had a grounding issue before, I worked on so many they run together after a while. This is the first time I worked electrically on this house, though, so it's not the same house. Before I saw your post I became more convinced it's a neutral problem. I get this sinking feeling that I'm going to have to go into every light switch, outlet and fixture and check every connection til I find the culprit. Quite an arduous task to say the least. Yes you are correct, this is an older home and remodeled a number of times and has a mix of old and new wire. No K&T that I can see and much of it was upgraded to romex. Here is another tidbit of info. The prior tenant I learned was frequently having to change light bulbs as they'd burn out more quickly. That tenant never complained, thinking that since they came from the dollar store they were just cheap. I learned also the present tenant is having to replace bulbs also. Of course I see why, a bulb isn't designed to take 133v and with 133v kicking on one leg for a bulb made for 120v then sure, they'll pop. And they're probably blowing on fixtures that are on the 133v leg. This is frustrating, thinking I had it figured out only to find out it may not be the AC units after all. As to the hair dryer running slow with no heat, I'll bet that outlet is on the leg that dropped down to 109v. As to a possible bootleg given what I've seen it's entirely possible. If I go around to every fixture, switch, etc, I may find the bootleg if it exists. I took today off my other project to work on this project. I have to resume my current project tomorrow. I'm not inclined to believe there is an immediate danger to the occupants. Would you concur? I mean we're talking an 10 add'l volts on a leg. If you disagree then maybe I need to stay on resolving this now. By the way, I read NO voltage on the ground wire to the ground rod. Nothing. 0. More muystery.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
"As to the hair dryer running slow with no heat, I'll bet that outlet is on the leg that dropped down to 109v.""On Saturday the tenant was in their 3rd floor bathroom using a hair dryer. The tenant said when they turned on the dryer it was barely blowing air and it wasn't even warm air. Sorta running like an ultra low speed. About a minute later a breaker popped. They reset the breaker and the dryer behaved normally, blowing hot air as if there were no problem at all prior to."That could be read several different ways.If the blower was on the same leg as the the AC it would be slow and little heat.If it was on the same leg and same circuit as the AC then it would stop when the breaker tripped.I am am guessing that there was not a common problem with the breaker tripping and it was the combination of the dryer and the AC trying to start on reduced voltage that cause the breaker to trip.However, that is just speculation and really an immediate concern."Before I saw your post I became more convinced it's a neutral problem. "IT IS A NEUTRAL PROBLEM.Let me clarify. The problem with meausring a high and low voltage at the panel with changes in load is a neutral problem.A PROBLEM BETWEEN THE PANEL AND THE TRANSFOMRER. MOST OF THE CONNECTIONS ARE POCO. I DON'T KNOW HOW MANY TIMES THAT i HAVE TO REPEAT THAT.It has nothing to do with any individual circuit.AND IT IS A SERIOUS PROBLEM. AT THE CURRENT LEVEL IT IS MARGINAL. BUT THAT HIGH RESISTANCE MEANS THAT IT IS GENERATING HEAT. HEAT THAT CAN START A FIRE OR CAUSE IT TO GET WORSE.All of the other things that I mentioned are only possibilities of how the water pipe might have been affected before you bonded it.But you need to get the neutral connection fixed, first. Then worry about the rest..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Edited 7/29/2008 4:55 pm by BillHartmann
ok ok, it's a neutral problem I get it :)I already have a trouble ticket with POCO created. I expect them to look at it soon. I asked them to please be sure their connections are correct. I am hopeful maybe tomorrow they'll check it out. I believe you when you say you think it's likely a POCO connection. That would certainly explain why after I turned off the ACs I still had the different readings after I had thought it was the ACs. I didn't mean to marginalize the seriousness of this. I've known for years that a loose neutral is a bad bad thing. I've just never come across one before, this is my first time of facing something like this so I'm trying to digest all of these symptoms and understand and make it make sense with all the info you've given me. When I was downplaying the seriousness I was only meaning that I didn't see an immediate danger to the tenants and that I recognize a problem still exists and must be addressed because it IS as serious issue. I just didn't believe there was any immediate danger at this point to the occupants. As much as I've been baffled by this I"m glad I'm experiencing this issue, I'm learning an awful lot of new things as a result of this and it's a bit refreshing to have something new and challenging and educational. When I saw the melted coax today I was like "wow" never saw such a thing or ever considered it ever happening. Then to see it, it makes me quite resolved, and thankful for you advice, to get it fixed. If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Neutral is meant to be at 0 volts, if the connection is "poor" somewhere the power takes the easy route and you get "odd" voltages.
Take it all the way out and you could get 240 at the socket!
Yes its a pain but check all the neutral connections in the main box. Check all the connections on the circuit showing trouble. I'm sure your find a poor connection.
POCO just called, they went out and checked all their connections. Had the tenants put it under full load and he's measuring ONLY at the meter base and getting steady 122/122 each leg. So I guess that means something is wrong with the neutral between meter and panel. The run from the meter to the panel is about 35ft. It's 100Amp SEU cable. My connectoins are tight at the panel I know as I checked all of them. I did not check it at the meter base, it may be loose there but I did do a visual of it today and it appeared to look fine inside the base. So with the POCO saying they're getting no fluctuations, but I am at the panel, it's got to be between the base and panel, that's all that's left.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
I was helping when a friend of mine had her service changed out and upgraded to 200 amp.Don't know what the orginal service was. It has 100 amp panel and it had been changed out at one time and there where sizes of overheating. And the meter had been replaced with a 200 amp meter.But the SE was probably still the orginal from the 50's.When he started to move the old meter to the side and setup a temporary connections the insulation started cracking and the wire arcing..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
"When he started to move the old meter to the side and setup a temporary connections the insulation started cracking and the wire arcing."Really? I guess I should not be surprised. I just replaced an old 200A SEU last month. It was a 50' run. Owner kept complaining of water pouring into his elec panel. I could not find how or where water was coming from. Until one day Iwent over as it was raining and discovered water dripping out of the SEU from the top of the meter entrance. Puzzled I reasoned water was blowing in thru the weatherhead. I get up on ladder to look at weatherhead and look down and lo and behold the insulation on the SEU was brittle, cracked and peeling like potato chips. Rain was getting inside the SEU jacket and filling the wire with water and the water was pushing all the way to the meter entrance. Anyways....sounds like you're agreeing with me, that I likely have a problem between meter and panel in the SE cable. It is old cable, looks very weathered and worn. I think we may be on to something. I'll find out tomorrow morning.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
If you did not do so then check the voltage right on the neutral wire at the lug on the panel.Most unlikely that there is a problem with the lug/bus and if so you should have seen it. But just to eliminate that possibility.I suspect that the old SE is OLD and thus is probably best just to replace it..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
What Bill said.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
Bill,
For all that are interested, we FINALLY located the problem. You may want to refresh up on the thread in case you forget what this was all about.
It's been about 6 weeks since this melting coax problem occured and I was pulled in on it. I am not the most experienced electrician and so I eventually had to call in a master who was willing to show me and teach me how to properly troubleshoot the issue. The problem turned out to be the neutral is going bad somewhere from the service head to the electric panel. Some water is likely in the line, or moisture and corroding the aluminum reducing conductivity. All the stray voltage was going straight to the ground, 13 Amps worth !!! It would only happen under heavy load.
We proved it was this becasue the POCO bugged a wire onto their neutral ahead of the owners side and ran it to the panel. The voltage imbalances were fixed and no more voltage to ground occured. Visual inspectoin of the SEU Neutral shows it looks perfectly fine at every connection point. However somewhere somehow there must be deterioration of the neutral inside the jacket rendering it unseeable.
As to how current was getting on the cold water pipe BEFORE I provided a bonding means to the cold water pipe (recall the panel was not bonded to the water pipe at all when I first arrived) and then frying the coax cable, we have the answer.
The answer is as follows: The hot water heater. The bad SEU neutral was causing current to be thrown over to the grounding wire and since the grounding wires are bonded to the neutral at the panel, and since it couldn't get back to the transformer thru the bad SEU neutral like it should otherwise do, it was instead following a path thru the grounding wire at the HWH, which is connected with 1/2" copper to the plumbing system of course and from there it jumped onto the grounding wire from the cable companies coax, pushing well over 13 amps thru the coax frying the #### out of it. The cable company has a bonded connection on the pole to the transformer ground wire coming down the pole and it was finding it's way back to the transformer that way. In other words, the electricity took a rather leisurely scenic route back home instead of the shortcut (SEU Neutral).
I'm replacing the SEU tomorrow. It's about 75' of 100A SEU so there's plenty of places the aluminum could be bad along the way. This house had other problems we found along the way, scary ones. We fixed them all. If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Thanks.That is kinda what I suspected..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Well I realize you suspected that. To the extent that it was a neutral problem that is. You may have suggested the SEU Neutral as well but some of the diag testing I did I interpreted as it was ok. Regardless, the issue is fixed, and like most posters who replied to me, including yourself, you all were correct.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
I guess I'm a bit stupid. On post #8 of 21 of this thread I deducted it was a neutral problem between the meter and the panel. I don't remember what i was thinking at that time but whatever it was I was hot on the trail to finding it. Somewhere I got sidetracked. I will attribute that to my level of inexperience. The master electrician I got to work with me took me under his arm in this case and taught me a LOT and even pushed me to learn to where he had me working on live connections with the RIGHT tools of course. He showed me a number of tricks of the trade he used over the years, and showed me the invaluableness of buying a Fluke 87 and Fluke 97 for that matter. The amountof knowledge I gain is priceless. So while I was stupid, ignorant, whatever you want to call it, I am now all the more wiser and will be able to help someone else, perhaps on BT. I feel rather blessed to say the least that a man would take me under his wing like that and spend the time to teach me vs. just show me and move on.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Well it is about time! Ihave been biting my nails for weeks! LOL!! Congrats!
"It is what it is."
You gonna open it up and show us the bad spots?
What the SEU cable jacket? Hmmm, never thought of it. I may do just that. I could see it furthering my education even more because seeing adds to understanding.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Like I said, bad neutral connection from the power pole. Everything you measured is consistent with that.
I wasn't disagreeing at all with you nor not trusting your advice. This is something I'm realy "green" on and so I been trying to digest it all. In my one post I mentioned the POCO cameout, said all their connections are tight. That leaves it only being from the meter to the panel. I will attempto to prove this Wednesday morning.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
I hear you - but your description matches our experience with a loose pole neutral to a 'tee'. We had to really pester the POCO until they fixed it. Once they did all problems went away. Older house too.
Jeff
Any new developments with the coax mystery?
"Preach the Gospel at all times; if necessary, use words." - St. Francis of Assisi
Other than what you read in this thread so far, nothing new. I won't get to go over this weekend as planned but I will sometime in next few days.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME