unstable, fluctuating house current?

[David Fraleigh]

My house has been plagued by dimming lights for quite a while and finally yesterday I decided to explore the situation and came up with some results that have me stymied. I put a voltmeter into the various outlets throughout the house and saw that the voltage would read at

118v for a while and then would suddenly shift to reading 127v. When this happened the lights in the room would either brighten or dim. This would alternate every few minutes.. I then went to my breaker panel and shut off my main breaker and checked the voltage situation on the lead in wires and saw that it was a steady 240 between tge two lead-ins but that the same instability occured between the individual leads and the ground/neutral.. (It would be 118 to ground and then shift to being 127 to ground every few minutes with the other wire reading the opposite at the same time). I went to a neighbor who comes off of the same transformer and asked him if he had the same light dimming problems and he said he hadn't noticed it but he said that his light bulbs were always burning out after just a short while... Anyway I am assuming that the problem is with the utility transformer but just wanted to know if this fluctuating current is typical of a bad transformer or could my ground connection possibly be causing this to happen... Thanks for your help. David

[Stu]

Call your REC. They will check it out. I had the same problem several years ago. Turned out to be a loose connection behind the meter.

[Joseph Meehan]

That sounds like a floating ground. It may well be in your home. Do you, by chance, have aluminum wires? If you have aluminum wire, it is likely your neighbor also does. You don't need aluminum wire to cause the problem, but it is often the problem. I suggest you consider this possibility first. Next step would be to contact the utility company.

[buffalobill]

and your neighbor's voltage is______?

[Neon John]

This is usually an intermittent neutral problem. When the voltage goes up on one side of the line, the voltage dips on the other. The voltage changes as loads vary if the neutral is disconnected, high resistance or intermittent and can't carry the neutral current.

You can check this with two meters. Connect one meter to one side of the incoming power and neutral and the other meter to the other incoming line and neutral. Then turn on and off 120 volt loads around the house, the larger the better. If one meter goes up and the other goes down, then the neutral is bad somewhere.

You need to get this checked right away, as when the neutral finally opens up completely, destructively high voltage will appear on the lightly loaded side of the box. Poofed appliances and even fire is possible.

The problem is usually with the utility equipment so I'd place an immediate call to the utility and report the problem. Utilities tend to jump on these kinds of problems quickly because of the potential liability. If their bad hardware causes a fire, especially after it's been reported, they get to pay. I bet they'll have someone out within an hour or two of you calling it in.

John, retired utility dude

[ds549]

you probably have have a bad connection on the ground (nuetral) wire. ive seen it many times. i bet your getting shocked quite a bit to touching metal things in your house too. usually the electric company will disgnose and fix that for you. lucas

[Louis Boyd]

Sounds like the neutral (not ground) between the the utility companay transformer and your breaker panel has a poor connection. Check it at your panel and if that's ok if it is call the power company to check at their transformer. The fluctuations come when the load within your house isn't equal on the two 120 volt phases. That's likely to happen when a load changes, such as your refrigerator turning on and off automatically. This needs to be fixed immediately as devices on the more lightly loaded side can by damaged by the overvoltage.

Your tests were good. Without knowing the 240 was stable at entrance panel there would be other possibilities. I'd repeat the tests at the te breaker panel and confirm with the voltmeter that phase A to neutral plus phase B to neutural voltage is approximately equal in magnitude to phase A to phase B voltage withing two volts and that Phase A to Ground minus phase B to ground is larger than about 2 volts. If that's true it confirmes the above suspicion of a loose or open neutral. By code both the neutral at your entrance and the neutral at the transformer are grounded, but if there's not a good metallic conductor (the third wire) between them any current unbalaance will show up as a difference in phase voltages. Earth grounds usually have several ohms of resistance, possibly a lot more depending on soil conditions.

[Bob_W]

I'll vote along with Neon John based on the information you have provided. The problem could be on either side of the meter. (Yours or the utility company.) One thing that is almost necessary to isolate this problem is a solenoid operated voltmeter (Wiggy). The high impedance of a conventional VOM (analog or digital) can really lead you down the wrong path.

Bob

[crmay]

Don't play with high voltage unless you have an ugly wife or a leprotic dick.

Call an electrician

[Don Bruder]

You've got a potentially serious electrical problem. Right now, it's

*RELATIVELY* minor, but if it's what I think it is, it can quickly go from minor to catastrophic, and do so with little or no warning. Sounds to me like your neutral is "floating". If you're not up to dealing with electricity (Sounds like you've at least got a clue), now's the time to call in somebody who is - PRONTO. As in "before it starts eating electronics, or worse, burns the house down."

Assuming my diagnosis based on your symptoms is correct, you need your neutral line tied together solid from end to end. Could be as simple as twisting a screw in the breaker box, or might need new wiring run - No way to be certain from this vantage point. Whether you take care of it yourself, or call in someone to do it, it's something that needs to happen ASAP if you don't want to come home to discover you're the proud owner of a brand new computer, complete with blown motherboard, or even worse, a smoldering pile of rubble.

[John Hines]

It is a loose neutral connection at the transformer. Call the utility company and report the problem of "open neutral" at the transformer, with voltage fluctuations affection both you and your neighbor.

The possibility of it being your problem is negated by it affecting your neighbor.

[Larry Caldwell]

Bad neutral. It's a dangerous condition. Fix it.

[Larry Caldwell]

Fortunately, there are no high voltages in house wiring.

[CJT]

Everything's relative. They're high enough.

[Pop]

[myself]

Ask your neighbor to meter his voltage. That should tell you more. There could be a bad transformer or a loose neutral at the pole.

[Don Bruder]

Maybe not relatively speaking, but 120 is more than plenty to punch your clock permanently...

[Edwin Pawlowski]

Larry may very well be correct. Have you checked any of your neighbor's voltage though? I had a problem with fluctuating voltage in the morning, hitting 135. Power company had a problem at a sub station.

[Moe]

I had the same problem at my house but didn't now it. I thought I had a bad washing machine because it would not spin dry. The cable TV service would also go fuzzy. I was checking the cable and learned that when I tightened the cable connection near the entrance to the house it would clear the cable picture, and finally once when I went out to tighten the cable connection it was warm to the touch, bingo! I called the electric company, they came right out didn't see much wrong but redid the service connections and that fixed it, the washing machine worked properly also. It was a bad neutral connection, barely noticeable, made just a spot on one of the bale connections. My house has a grounding rod, but I'd built a carport and it covered the area where the grounding rod is and the ground had dried out enough that it no longer provided enough ground. The TV cable had become the main neutral/ground path, and not a very good one.

[mm]

I'm pretty sure most people have never heard them called solenoid operated voltmeters. .If you want people to understand, I'd either explain what I meant, or call them mechanical voltmeters, (or electromechanical, or wire coil, or moving needle VOMs)

What is Wiggy?

Remove NOPSAM to email me. Please let me know if you have posted also.