House voltage varying up and down

   / House voltage varying up and down #1  

BeezFun

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Location
IL
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Strange problem started today. I turned on coffee pot (1500W) and lights over kitchen sink dimmed slightly. Plugged the coffee pot into a different outlet in kitchen and turned it on, this time lights got slightly BRIGHTER. Went and got my voltmeter, voltage measures 130v without the coffee pot plugged in, drops to 115v and rises to 145v depending on what outlet I plug coffee pot into. Tried same experiment using a small space heater (1500w), same results. I haven't tried every outlet in the house, but I've tried this in 3 rooms and get the same result. Any thoughts what's going on, and where I should look next?
 
   / House voltage varying up and down #2  
Beezfun I am not an electrician by trade, but I am sure one will chime in soon. In the meantime if it were me I would check the voltage at the main feed coming into the house to see if the problem is outside or in the house. Please be careful in the box!
 
   / House voltage varying up and down #3  
Usually the problem is a bad common wire connection in the service panel.
 
   / House voltage varying up and down #4  
I would check to be sure you haven't lost power on one of the two incoming hot leads. It sounds to me like you have and power may be back-feeding. The utility co should dispatch a lineman if it turns out the problem is outside of your responsibility.
 
   / House voltage varying up and down #5  
Is the voltage at the outlets varying? Or is it the main panel that is varying?
 
   / House voltage varying up and down #6  
Usually the problem is a bad common wire connection in the service panel.
Yes, the neutral splice at the service entrance or pole splice is likely bad. I have
had this problem before. It was caused by the electric company failing to use
dielectric paste at the meter connection. Our overhead wires are aluminum around here,
and you can expect problems with these connections in 5-15 years, if no anti-corrosion
paste was used. I made the utility redo all the service entrance connections and splices.
 
   / House voltage varying up and down #7  
Beezfun,
Is it windy in your area? I have had trouble here with the wind shaking wires, branches, etc which caused the voltage to fluctuate. I called the local power company and it took them two or three tries to finally eliminate the problem. Never did get find out what they fixed. My voltage would float from 96 to 125 VAC with out any load change. Like you likes would dim and go bright etc...

They checked my service to the house and it was coming from there line.

good luck
 
   / House voltage varying up and down
  • Thread Starter
#8  
I think I figured it out. On one hot leg in the service panel I have 105v, the other leg 135v. Went over to the neighbor's house, he has the same problem. We both hang off the same transformer on the pole out front, so I'm guessing that could be the problem. It's also been very windy around here the last few days (thanks oldnslo), so it's possible that's causing some of the problem. I called the power company, they're going to send someone out to check on it.

I still need someone to explain how turning on the coffee pot can cause a light to get brighter...
 
   / House voltage varying up and down #9  
Like dfkrug said, the problem could be with "aluminum" wire connections. Depending on your power suppliers, they may come out and check it of fix it. Then again, they may say that their responsibility ends at the splice at the weather-head.

Regardless, the connections need to be checked and this usually requires pulling the meter and this usually requires the power company.

I have seen this before and most of the time it is these types of connections.

However, has it been unusually dry in your area? I have also seen a case where the ground rod had to be watered to correct a power problem since the ground was too dry to give the house a ground. They even drove the ground to 24' deep, but since the house sat on a "sandy hill", when the weather got really dry, they had to water the ground rod.
 
   / House voltage varying up and down #10  
There is a problem with the neutral.
I had something similar when I lived in the city. I had 119 V on one leg and 126V on the other.
I called power company and they sent out 3 trucks that evening and changed my service line in the pouring rain!!
They seemed to think it was urgent, I guess there is some danger to the homeowner when this occures.
 
 
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