Voltage drop

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  #1  
Old 06-03-03, 10:30 AM
marseattle
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Exclamation Voltage drop

Hello! I'm new to this forum as of today. Pardon if I break protocol I don't know about, in advance!


HERE'S THE BACKGROUND:
I purchased my house in 1999, and since I've moved in, have noticed occassional dips in the current, via the lights dimming, or the ups on my computer alarming me to that fact. The inspector (who hadn't seen these 'dips') told me I should really replace the electrical panel (it was original equipment to the 1975 house, made by Zinnser). I did this myself, replacing with Square D panel. I still get the occassional dips.

They've become more severe as of late (within last 5 months). Three months ago, I was watching tv when it occurred, and the picture on the tv turned to a rainbow and disappeared. I'm hoping it's the power supply on the tv, but haven't repaired it yet. A small surge suppressor, only 3 months old (the strip type with six outlets and a switch), which I had on another television (which was replacing the original) failed yesterday. The suppressor smelled with the acrid smell of something gone wrong electrical. Maybe it was just doing its job, but I think my situation is an undercurrent, not an overcurrent, one.

I thought I'd isolated the event to be something with the water heater (it's electric), but this morning when the dimming thing was occurring, I went and switched off the water heater at the breaker, and the dimming continued.


AND NOW MY QUESTIONS:
I'm wanting to know how dangerous my situation is, and what I should do to trace it to its source. I've asked two neighbors (I'm in a cul-de-sac with six other homes, and we share a transformer for underground supply), and they say they aren't experiencing anything like what I'm describing here, so I don't think it's from the supply. Maybe I'm naive or ignorant, but I'm thinking that if something within the house is drawing the current and reducing the voltage, it would trip its breaker if this continued very long (the duration of these lags is about 4 seconds tops).

I'd appreciate any insight into this dilemma. Sorry for the essay!
 
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  #2  
Old 06-03-03, 11:58 AM
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Did you replace the meter base when you replaced your main panel? You could have a corroded conection in your meter base that is causing the problem. There is good chance that you have an underground wire that is failing. The insulation could be damaged just enough to allow ground moisture to make contact with the conductor and allow voltage to "leak" into the ground. Do you notice the problem more after rain? Have you noticed worms coming out of the ground? If you haven't already, you should contact your power company and explain what is going on. They can come out and "meg" the wires and find out if there is a problem.

Or, you may need to call Ghostbusters.....
 
  #3  
Old 06-03-03, 12:06 PM
marseattle
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I didn't replace the meter base. The power company came and resealed the meter box. Don't know if they inspected it then, they just sent me a $37 bill to reseal it. ;-) I didn't see any bad looking connection there.

It does feel like I need Ghostbusters. So, is my logic correct that is isn't something in the house drawing the current, since no breakers are tripping? All the breakers are correctly sized for the wires they protect.

We've had dry weather last few days here. I did water the plants around the house perimeter yesterday.

I'll call them immediately and have them come verify it isn't them, or fix it if it is.

Any other troubleshooting you or anyone can suggest would be appreciated.
 
  #4  
Old 06-03-03, 12:19 PM
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$37 to reseal the meter!!!! I'm assuming that when you installed the new main panel you cut the tab on the meter base and pulled the meter to kill power to the main panel. Then they came out and charged you $37 to put on a new plastic tab. As far as I know, they haven't started charging for such a service in my area.

When you experience the dimming, the entire house is affected, correct?
 
  #5  
Old 06-03-03, 12:35 PM
marseattle
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Yes, I 'see' it in the lights immediately. My computer is on a separate circuit from the lights, and the ups it's connected to alarms when this condition is occurring (it goes to battery delivery instead of line, and alarms when the switch occurs). I do see it also in a lamp at my bed, which is on a third circuit, I believe.
 
  #6  
Old 06-03-03, 12:45 PM
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Other possibilities:

The circuits you have described are all fed out of a subpanel where a bad connection exists.

Your 200A amp is not adequate and every time your 5-ton A/C compressor kicks on your already overloaded service experiences a voltage drop with the resulting dimming of lights.

You have a "bad" neutral somewhere in your system (probably power company side) that when it arcs and crackles actually sends an overvoltage to your circuits - the "dimming" you are seeing is actually a pulsing voltage.
 
  #7  
Old 06-03-03, 12:51 PM
marseattle
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No 5-ton AC going on here (we usually don't need to do AC in Seattle, I don't even have one ;-)).

I am 99% certain no device within my home is activating and causing the flickers. Water Heater was the only thing I thought could be it, but when I turned off the breaker to it this morning, and the flicker continued, I figured that eliminated it as a source.
 
  #8  
Old 06-03-03, 12:57 PM
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Water heaters don't usually create the type of problem you are describing. The start-up torque of a motor is usually the culprit on dimming lights on an undersized circuit or service.

Since you just replaced your main panel, I would look from the meter back to find the problem. If the problem is in the meter base, it is your responsibility to fix it. If it is between your meter and the transformer, it belongs to the power company. The power company should be able to determine if the problem is theirs.
 
  #9  
Old 06-03-03, 12:58 PM
marseattle
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By the way, thank you so much for the replies thusfar! I appreciate the flow of information. I've been worried a bit about this situation since I first experienced it.

Called the power company. They're going to send a crew to check out my service, and the meter base. So, what does 'meg' mean? Since this is an intermittent issue, is there a way they can know for sure that all is ok?

Also, since i've lost two surge suppressors now, maybe overvoltage is indeed what's occurring.
 
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Old 06-03-03, 01:16 PM
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Megging a cable is done using a high resistance meter to test the cables insulation. It will reveal if there is a flaw in the cables insulation (i.e. a rock has pierced through the insulation of one of your underground cables).

Your situation sounds like a classic case of a bad neutral. Either the neutral wire underground has a problem, or the connection of the neutral in either the transformer or the meter base is faulty. If the connection totally broke down then your current flowing through your 120V lines would not have a return path to the transformer and would find another route back through the other 120V phase via a water heater element or some other 240V circuit. The result would be 240 volts across your light bulbs and televisions which cannot handle the overvoltage. When you have a corroded connection, you have intermittent arcing which causes fluctuations in the voltage. When the neutral is the corroded connection, the voltage pulses above 120 volts.

Do your light bulbs tend to burn out quicker than they should?
 
  #11  
Old 06-03-03, 01:39 PM
marseattle
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Bulbs go quicker than I'd expect. Those fluorescent bulbs which have their own ballast (and screw into a socket) never last the advertised timeframe. Can't say honestly if the others go faster, as it always seems too fast for me (I don't keep good track of that). I have halogen screw-in bulbs in most of the house, some on dimmers. The dimmed ones seem to live quite a while, but maybe the dimmer is isolating what's going on there.
 
  #12  
Old 06-07-03, 08:04 PM
Snapper6356
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sounds like a problem i had once. Finally got worse then went out all together one night. Turned out one of the wires up on the pole was messed up and not contacting good. It acted just like you described, lights would dim for no reason. finally one night over half the house went out while the rest were on. Only one leg went out on mine. so i bet it is something on the company side.. Hope this helps..

snapper
 
  #13  
Old 06-09-03, 09:26 AM
marseattle
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Well, the power company came out, and knew in ten minutes that it was something in the feed to my house. So, ha!, it was them!!! It was good to know that it wasn't within my house, as I was really out of ideas on what it could be.

They hooked me to the neighbor's feed temporarily, and said they're going to re-run the whole neighborhoods feeds (seven houses). The line is 28 years old to these homes, and they think they're due, I guess.

I'm going to file a claim to get my satellite receiver and tv repaired/replaced, since they have identified their service was at fault. We'll see where that goes.

Thanks again mcjunk for all your suggestions and comments. You were right on the money with the problem, and I'm glad to finally have it known and soon to be resolved.
 
  #14  
Old 06-11-03, 06:03 AM
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Did the power company tell you the exact nature of the problem? Not that it really matters, but did they say if the problem was in one of your feeders underground or in the transformer itself? Also, was the culprit a "phase" or "neutral" wire? My guess would be the neutral wire because as I believe I went into above, a faulty neutral creates problems with overvoltage whereas a faulty phase wire usually creates problems with undervoltage. Of course the arcing and intermittent voltage created by a bad phase conductor can wreak havoc on electronic equipment as well. A bad transformer can create all kinds of problems.

Glad to hear you about have the problem resolved.
 
  #15  
Old 06-11-03, 10:37 AM
marseattle
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The power was in the feed to my house, not in the transformer. I didn't get from them if it was the neutral or a 'hot' line, so don't have those specifics.

The other neighbors weren't experiencing any issues, so I had eliminated the transformer as the item (all seven houses are fed by one transformer).

If I'm around when the come and do the work, I'll enquire what the specific problem was.

Funny, but when they tapped me into my neighbor's feed, they must have bumped into my gas meter, and tripped the earthquake valve. I realized yesterday I no longer had gas service. That was an easy fix, though.
 
  #16  
Old 06-11-03, 11:11 AM
marseattle
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Oops, a typo. I meant the 'problem' was in the feed. The power should be in the feed.
 
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