Bathroom lights are dim, voltage is low?

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Mar 8, 2012
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MO
Could cold temperatures cause dimming lights? We were going to bed last night and the 4 sconces in our master bath were noticeably dimmer. They have led candle base bulbs in them. I have a Kill-A-Watt that I plugged into the outlet and was showing 108 volts. I am pretty certain it used to show close to 120.

The meter was replaced a week ago with a smart meter by the power company but I never noticed any issues before last night. Checked voltage this morning in the bathroom and am getting 109.5 and those bulbs are still dim.
 
I’d chase it out. LED has low draw, something is loose.

But check some outlets, make sure your house is getting 120V. I can’t imagine the drop to your house is low, but it’s someone else’s problem if so.

These on a switch? Id start there, see if it maybe went bad. Then check outlet wiring, then start tracing back to the panel.
 
Just a homeowner here.
I would be worried more about the voltage going to:
► Furnace
► Refrigerator
► Sump Pump
Check the voltage at various outlets to see if it's a 'whole' house issue.
 
Just that one receptacle seems to be effected?

I've gone through a few candle base LED bulbs in our one bathroom. They dim when the drivers in them are dying. If all of yours went out at once, it's probably not that.
 
Thanks for all the quick replies. I checked other outlets around the house and am getting 109-111ish everywhere. I know the Kill A Watt EZ isn’t some super accurate piece of equipment but feel like it’s probably close enough for this purpose. The bathroom lights are definitely dim, that also the furthest distance from the meter.

The house is 8 years old, fwiw.
 
If you’re taking a volt meter to stuff, make sure it’s at room temperature. It’s rare, but they can explode when very cold and exposed to voltage. Without going into meter ratings and such, extreme cold will cause condensation inside the unit and it could go boom.

I agree with the others on checking other circuits first, but since you just noticed it in the bathroom, I’m betting it’s just that.

*Just saw the above reply.
 
Definitely too low, but not a Christmas Eve emergency.

Id tell you to start at the lugs on the panel next if you’re comfortable with it. Wear safety glasses.

Seems odd this all happened after the meter replacement. With it being a smart meter, you can’t just pull it unfortunately to check the power in from the utility. If your panel’s main lugs are low as well it could definitely be the power companies issue and is worth calling them today. Maybe they can read your voltage with the smart meter. I’m not sure.
 
I doubt that the problem has to do with the recent meter change. With the current temperatures, a lot of heat pumps can't keep up and are using heat strips. The excessive demand can cause voltage drops. Since you didn't notice the problem until the arctic express hit I would bet that is what you are experiencing. Check the voltage again after temperatures warm up.
 
Could be sagging voltage on the grid.


That was it. Just got off the phone with Ameren, hats off to them for the quick response on Xmas Eve. The guy flipped a switch at the substation and that got the voltage up to 114. He said my neighborhood is at the end of the line from the substation and to keep an eye on it. They can come out to record the voltage over time if it continues to be a problem. 114v is the minimum that they tolerate, as I type this it’s drifted back down to 112.0.

I texted a neighbor who had the same issues, so it’s not something internal to the house. Hopefully it doesn’t trash any circuit boards.
 
Ask a neighbor that shares you transformer - unless you have your own transformer - ask them anyway to get an idea on if there is a sag on the grid - sounds extreme though. I Never saw ours below 117at the house, the grid has compensators to maintain voltage.

Can you meter the 240v power right at the main panel?

I was wiring a generator into an old water heater circuit two days ago, I had 240V exactly through 30 feet of (32y.o.) copper romex 10/2 from the main panel.

I don't like the smell of this situation.
 
I’d chase it out. LED has low draw, something is loose.

But check some outlets, make sure your house is getting 120V. I can’t imagine the drop to your house is low, but it’s someone else’s problem if so.

These on a switch? Id start there, see if it maybe went bad. Then check outlet wiring, then start tracing back to the panel.
I had that issue in my first house. neighbors kept having appliances go bad too. I checked and everything had low voltage. I had the electric company come out to check the power and it was a problem at the poll and many houses issues were fixed at that point
 
Ask a neighbor that shares you transformer - unless you have your own transformer - ask them anyway to get an idea on if there is a sag on the grid - sounds extreme though. I Never saw ours below 117at the house, the grid has compensators to maintain voltage.

Can you meter the 240v power right at the main panel?

I was wiring a generator into an old water heater circuit two days ago, I had 240V exactly through 30 feet of (32y.o.) copper romex 10/2 from the main panel.

I don't like the smell of this situation.

I don’t have a voltmeter with a good battery at the moment. I was just using a Kill A Watt EZ to measure a normal outlet. My neighbor has the same issues as me so I think we’ve narrowed it down to the incoming power after speaking to the power company. Hopefully none of my appliances or furnaces are impacted and this is a short term thing with the extreme cold we’ve had. They did say I could make a claim if something is damaged, but that doesn’t do me any good when it’s single digits.
 
Just diagnosed my neighbor...same issue. Turned out that the ground was bad causing low voltage on the 120 circuit. Pole was replaced but the ground rod was loose in ground along with dry dirt it was in. The ground by the box in basement was rotted off and the pole trany is a long way away. If the 240v is good it probably is the ground. Check for 240v..that will tell ya..
 
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Just diagnosed my neighbor...same issue. Turned out that the ground was bad causing low voltage on the 120 circuit. Pole was replaced but the ground rod was loose in ground along with dry dirt it was in. The ground by the box in basement was rotted off and the pole trany is a long way away. If the 240v is good it probably is the ground.

A bad ground will NOT cause wandering voltage on the 120V legs.

A bad neutral WILL.
 
A bad ground will NOT cause wandering voltage on the 120V legs.

A bad neutral WILL.
Yea...its been awhile...the neutral and ground are one when they enter the box..with a ground near box and one at the pole. If the ground between pole and box is poor..or should say neutral/ground....also the pole with trany is blocks away..

Our electrical grid setup is over 100 years old. Codes might be different elsewhere..
 
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