Washing machine causing lights to Dim

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crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
I had a call come in and the customers washing machine was causing the lights to dim a bit when the machine was agitating. I checked the connections in the panel and meter socket and everything seemed fine. I hit them with infrared and no hot spots. I noticed that one leg had 130 volts and the other had 118 at the meter base. I tried moving the washer off of the leg that had high voltage and no change. I noticed that the terminations at the weather-head were still the temporary type made by the electrician who installed the service. I called the poco to finalize the connections and to also reseal meter socket. Anyone ever encountered something like this before? It was a simple domestic washer 120v. I was concerned about a loose neutral but didn't find anything, I also tried a new breaker and no change. The washer was drawing between 3 and 6 amps when it was going through this cycle. Any suggestions on other things to check?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
With one leg at 130 and the other 118 there is a neutral problem. It sounds like you pulled the meter to measure the voltage with no load? POCO problem. Don't know if it's the temp bugs or something else.

-Hal
 

kwired

Electron manager
Location
NE Nebraska
sounds to me like it is probably a neutral issue. connect a heavier load like a hair dryer or electric space heater (120 volt), if the voltage to neutral goes off balance while loaded then poor neutral is likely what you are looking for.

Extremely long small conductor runs or too small of supply transformer can cause similar issues, but those are more rare and you are probably looking for a neutral issue.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I had a call come in and the customers washing machine was causing the lights to dim a bit when the machine was agitating. I checked the connections in the panel and meter socket and everything seemed fine. I hit them with infrared and no hot spots. I noticed that one leg had 130 volts and the other had 118 at the meter base. I tried moving the washer off of the leg that had high voltage and no change. I noticed that the terminations at the weather-head were still the temporary type made by the electrician who installed the service. I called the poco to finalize the connections and to also reseal meter socket. Anyone ever encountered something like this before? It was a simple domestic washer 120v. I was concerned about a loose neutral but didn't find anything, I also tried a new breaker and no change. The washer was drawing between 3 and 6 amps when it was going through this cycle. Any suggestions on other things to check?

I had this exact issue with my own washing machine at my previous residence. The machine was at the opposite end of the house from the service, and each time the agitator reversed direction the lights would dim. The current draw was sufficient to drop the voltage on the entire circuit. The solution was a new panel (for other reasons as well) and a dedicated circuit for the washing machine. No problem after that.
 

kwired

Electron manager
Location
NE Nebraska
I had this exact issue with my own washing machine at my previous residence. The machine was at the opposite end of the house from the service, and each time the agitator reversed direction the lights would dim. The current draw was sufficient to drop the voltage on the entire circuit. The solution was a new panel (for other reasons as well) and a dedicated circuit for the washing machine. No problem after that.
You apparently had lights on same circuit as the washer and were just experiencing voltage drop on that circuit.

OP has 130 and 118 volts to neutral on ungrounded lines (presumably at service) which seems to indicate a problem upstream from the branch circuit with the washer on it.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
You apparently had lights on same circuit as the washer and were just experiencing voltage drop on that circuit.

OP has 130 and 118 volts to neutral on ungrounded lines (presumably at service) which seems to indicate a problem upstream from the branch circuit with the washer on it.

The OP says "causing the lights to dim". If he clarifies that they pulse in time to the agitator, I'd suggest my observations are closer to his issue.

He may also have a neutral issue, but I don't believe it's related to his observation. Or more correctly, his customer's observation.
 

kwired

Electron manager
Location
NE Nebraska
The OP says "causing the lights to dim". If he clarifies that they pulse in time to the agitator, I'd suggest my observations are closer to his issue.

He may also have a neutral issue, but I don't believe it's related to his observation. Or more correctly, his customer's observation.
130 to 118 volts is a fairly significant imbalance. If it drew one leg down to 118 but other one remained fairly steady (probably about 124 in his case) then you would be looking for poor connection on ungrounded conductor, voltage drop because of conductor length, etc. Even with a poor neutral the light dimming will still pulse in time to the agitator as that is causing a load change that results in voltage change also.

If I were him I be starting at service equipment and applying an unbalance load there to see how voltage on service conductors responds. If that throws off the balance there is problems upstream toward the source - and if something that just suddenly started to happen - about has to be in the neutral. Undersized transformer or extremely long service conductors would have done this ever since they were installed.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
All sorts of ways to see if its the neutral or just voltage drop.

Best is more than one meter connected. Three is best. Two will work, as will simple test lights that Gar has suggested numerous times.

Turn off all loads:
Connect meter line A to neutral. Record V1 (124)

Connect meter line B to neutral. Record V2 (124)

.Connect meter line A to line B. Record V3 (248)

V1+V2=V3 Your meters may not be calibrated so minor deviations may be expected.

Turn on loads.

V1 = 118
V2 = 130
V3 = 248
Neutral problem.

V1 = 118
V2 = 124
V3 = 242
Voltage Drop.

Typically with a poor neutral you will see lights in part of the house go brighter as others go dim. I do not know how LEDs with the universal power supplies are affected. May not be at all.
Loading up one line with a hair dryer or similar will help pinpoint the problem
 

growler

Senior Member
Location
Atlanta,GA
With one leg at 130 and the other 118 there is a neutral problem. It sounds like you pulled the meter to measure the voltage with no load? POCO problem. Don't know if it's the temp bugs or something else.

-Hal

Had one just like this about a week or so ago. Funny what caused the customer to notice the problem was that a handyman had tried to trip a breaker ( short circuit ) to located the breaker to turn it off to replaced a pull string type fixture (keyless). He got the breaker tripped but it would not reset. Just about the same voltage measurements.

I knew it was a bad neutral so I called the power company and they found it. Bad crimp at a pole between the weatherhead and transformer. Thing is that crimp been bad for maybe 20 years and just showed up all at once. The linemen were taking it back to show it off because it was so unusual. One side of the crimp splice hadn't even been crimped ( who would have thought it would last so long).
 

crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
Thank you for all the insight and testing procedures, really can't thank this forum enough it is such a great resource. POCO just left, neutral connection was bad on the pole. Issue is gone. Have a great weekend everyone!:)
 

crispysonofa

Senior Member
Location
New England
Occupation
Electrical and Security Contractor
Had one just like this about a week or so ago. Funny what caused the customer to notice the problem was that a handyman had tried to trip a breaker ( short circuit ) to located the breaker to turn it off to replaced a pull string type fixture (keyless). He got the breaker tripped but it would not reset. Just about the same voltage measurements.

I knew it was a bad neutral so I called the power company and they found it. Bad crimp at a pole between the weatherhead and transformer. Thing is that crimp been bad for maybe 20 years and just showed up all at once. The linemen were taking it back to show it off because it was so unusual. One side of the crimp splice hadn't even been crimped ( who would have thought it would last so long).

I had this exact scenario earlier in the season too! Pole had been replaced and conductors spliced in the gutter that POCO installs going up the pole. Asked them to remove the gutter so we could try and move the wire as the ground was frozen and what do you know? Bad splice. Can't hurt to have them take a peak.
 

kwired

Electron manager
Location
NE Nebraska
Had one just like this about a week or so ago. Funny what caused the customer to notice the problem was that a handyman had tried to trip a breaker ( short circuit ) to located the breaker to turn it off to replaced a pull string type fixture (keyless). He got the breaker tripped but it would not reset. Just about the same voltage measurements.

I knew it was a bad neutral so I called the power company and they found it. Bad crimp at a pole between the weatherhead and transformer. Thing is that crimp been bad for maybe 20 years and just showed up all at once. The linemen were taking it back to show it off because it was so unusual. One side of the crimp splice hadn't even been crimped ( who would have thought it would last so long).
Barrel type crimp device? Here would never last 20 years on most service drop situations. Between snow, ice, wind something would eventually pull the conductor out of the device. If the thing were fairly secured so it can't move it has a chance though.
 
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