Crazy power fluctuations in the house! Weird.

[Ballvalve]

Help. I am a contractor and have done much complicated wiring but I am stumped. Lights flickered in the house [ 20 years old, no previous issues] for a few days then resolved. Now again power is variable on the 2 hot lines. sometimes 120v and others 105 volts, you can see the lights at a low power indicating low voltage. But it is not consistent, one leg lower than the other higher. Okay, went to the meter, its a "smart" meter and it is blank for the first time ever. Gave it the hammer, no improvement. So here is the bizzare part: 120V to ground both hot legs at the 200 amp main breaker. Then 11 volts between the two hot legs. 3 different test meters, all agree. Transformer? Meter? California mountains, recent massive rain and snow, 5 power outages, surges, lightening storms... ran on a genset for a week. Before I call big brother, could it be on MY side of the meter? Thanks.

 

[John Gayewski]

I'm not electrician nor do I have a good amount of experience with electrical work. But I do have experience with goofy electrical phenomenon. In my case the transformer lugs were loose. It took several trips from a union electrical contractors to figure out what was happening because the problem appeared intermittent. Not sure if that helps but in a lot of cases in my area it's free to call the utility and have them isolate your problem.

 

[Sponsor]

 

[Reach4]

"So here is the bizzare part: 120V to ground both hot legs at the 200 amp main breaker. Then 11 volts between the two hot legs."
11 volts between the two hots at the incoming wires, and you don't have access to a more-upstream point. Time to call for help. You have done all that you could do.

 

[wwhitney]

So here is the bizzare part: 120V to ground both hot legs at the 200 amp main breaker. Then 11 volts between the two hot legs. 3 different test meters, all agree.

One possibility here is that one of your hot legs is out from the utility and you are using a high impedance meter (typical). Then you are reading 120V through some of your 240V loads. You could try turning off all the double pole breakers in the panel to see if your readings change.

Of course, in this scenario half of your 120V loads should be out as well . . .

Cheers, Wayne

 

[Ballvalve]

One possibility here is that one of your hot legs is out from the utility and you are using a high impedance meter (typical). Then you are reading 120V through some of your 240V loads. You could try turning off all the double pole breakers in the panel to see if your readings change.

Of course, in this scenario half of your 120V loads should be out as well . . .

Cheers, Wayne

Reading the main breaker at the entrance panel with all loads to the house off, it is 82 volts to ground on one leg and 120 volts on the other. Transformer seems only issue... [?]

 

[Reach4]

Measure voltage from each hot to neutral.
Measure voltage from neutral to ground.

 

[Bannerman]

Your utility crew will likely pull the meter to disconnect your 'load' before measuring the voltage directly where the power enters the meter base. While the meter is removed, they will also inspect for evidence of overheated connections within the meter base which you will not be able to see while the meter is in-place.

 

[WorthFlorida]

If it is an aerial mask service entry, a poor connection from the house wire to the service line is bad. If there is one, the wires may be swinging from the wind. Either way the electric company has to be there to check there end first.

With all the storms and outages, a good chance it is the power company's problem. A tree down somewhere, flooding, etc.

 

[Fitter30]

Call your utility start there.

 

[Afjes]

Another vote to call your utility company.

Tell them you either have one leg out or a loose neutral. The service call will be free and they will make it a point to get out there quickly. This is the first place you should start.

 

[Ballvalve]

To conclude this, the power company saw 240 volts at the transformer and 215 and 145 volts at the meter and between the hots about 5 to150 volts. Pulled the 500' of underground wires in conduit. wires missing insulation and burnt for about 5 feet in one section and water in pipe. Lightening or fault in original wires and conduit. Done in 3 hours and all is fine.

 

[Fitter30]

My vote fault in the wires. Water in the pipe isn't anything unusual. If it was lighting think the wires would of been melted not just one and the meter would of been damage at a minimal.

 

[shieldcracker]

To conclude this, the power company saw 240 volts at the transformer and 215 and 145 volts at the meter and between the hots about 5 to150 volts. Pulled the 500' of underground wires in conduit. wires missing insulation and burnt for about 5 feet in one section and water in pipe. Lightening or fault in original wires and conduit. Done in 3 hours and all is fine.

Thanks for wrapping things up.