black phase down

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swat45

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I rewired a kitchen dining room and living room. Besides the abandond circuits, only one existing circuit was touched/ (changed switchbox location). I got a callback saying the power on the lights, laundry and garage went out two nights in a row around 12am. My first thought was a timer, dusk till dawn sensor, or motion light. I triple checked all my wiring and it was fine. When the circuits are down, the main panels Black phase is reading around 28V. The Red phase is fine? It's hard to chase when it all working fine. Today it was on in the A.M. then went off at 10 on the dot. I checked panel while everything was working and it read 120V across Red and Black. Is this a power company matter? thanks to anyone who could help me save some time.
 
Phase down.

Phase down.

I don't know? The customer states it just started. Either way it seems random and is off for extended hours. It is Santa Clara Power Co. so I wander if they have a phase issue or lugs are loose. That's my next check when it happens again. Every breaker in the main is a quad 20/ 30 30/20 plus one two pull 40. That would make sense, but once again....it just started 2 days ago.
 
PetrosA said:
Is there any chance this panel is being fed by an off-peak meter? They cut off one leg to shut down 240V appliances.
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An off peak meter would be more likely to be on during the night, but it is possible that it has an internal time clock and pulling the meter or other action stopped the clock temporarily. If so, the power company may have to come out to reset the time on it.
But even then, unless you moved load circuits from one phase to the other (to balance the load?) there should not have been a problem.

"It seems random" suggests a POCO wiring issue, but doing it at exact hour times does not.
Other possibilities are that the meter has been misconfigured for remotely controlled load shedding or is just defective.
Is this a smart meter with built-in disconnect contractors?
Measuring 120 from black to red is consistent with the phase wire being completely open on the line side and held to neutral by the connected loads.
 
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phase down.

phase down.

I moved two breakers, one spot down to add the 100 A sub breaker. The phases stayed the same. The meter wasn't pulled. and the 100 A was not turned on. When it (goes out) no breakers are tripped either. As normal, there is some funky wiring from the last electrician... But I did not mess with any of the existing? Weds will be my 3rd try. (if it's off) I was told to check voltage coming off the meter to confirm..... I hope it that.
 
swat45 said:
it is a smart meter.
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I don't think Santa Clara power has smart meters. Are you sure it is Santa Clara Power and it is smart meter?

For how long does it stay OFF? Is there a pattern to it?

What kind of load did the customer have ON when the power went OFF?

Plug in (2) hair dryers on "A" leg and let it run for 2-3 minutes and put on "B" leg and let it run for 2-3 minutes and see if you can duplicate the problem.
 
I had a customers home doing the same thing. It would drop one leg for about 30 min. then it would come back on. POCO found a bad crimp on the service riser.
 
We were having a problem where I used to work, that would spike the power in the computer room and trip the main. The problem would happen around 2 AM when there were really no other loads in the building.

Don't know the exact explination, but it had something to do with the POCO switching something every night and when we notified them, they said thank you, like they do, but the problem went away.

If it's a true smart meter, they can be shut off at their "office". With it being exact times I would think that it's a POCO issue.
 
If it is a smart meter and is shutting things off it should be opening both lines. If customer is current with bill payments it is not likely they are even being told to be shut down and if they are it is malfunctioning if only shutting off one line.


My first guess is you are losing a line, could be anywhere from the main or subpanel all the way to POCO transformer. I would start by putting some heavy loading on this service, like at least 1500 watts per line, but more is better. The more load you have the faster any weak connection will heat up. You probably have a condition where failure happens, then when things cool down it starts working again. If you have such a connection it will get worse over time and will happen more frequently and eventually maybe will remain in an open circuit condition indefinitely.

When you read 120 volts from red to black it was because there was 240 volt load connected, like maybe a water heater. Check voltage from line to line as well as line to neutral, both with circuits on and off. With no connected load you will not have 120 from line to line, you will either have 240 or nothing (or at least a very low value, but not 120)
 
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kwired said:
If it is a smart meter and is shutting things off it should be opening both lines. If customer is current with bill payments it is not likely they are even being told to be shut down and if they are it is malfunctioning if only shutting off one line.


My first guess is you are losing a line, could be anywhere from the main or subpanel all the way to POCO transformer. I would start by putting some heavy loading on this service, like at least 1500 watts per line, but more is better. The more load you have the faster any weak connection will heat up. You probably have a condition where failure happens, then when things cool down it starts working again. If you have such a connection it will get worse over time and will happen more frequently and eventually maybe will remain in an open circuit condition indefinitely.

When you read 120 volts from red to black it was because there was 240 volt load connected, like maybe a water heater. Check voltage from line to line as well as line to neutral, both with circuits on and off. With no connected load you will not have 120 from line to line, you will either have 240 or nothing (or at least a very low value, but not 120)
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I didn't explain it very well, but that's kind of where I was going. if you have a meter you could just unplug the meter and hook it up to the line side and see what happens, that would narrow it down on which side the problem is, but it could still be a bad meter, you could simply call the POCO and ask them to replace it and see what happens. KISS, easy stuff first.
 
cowboyjwc said:
I didn't explain it very well, but that's kind of where I was going. if you have a meter you could just unplug the meter and hook it up to the line side and see what happens, that would narrow it down on which side the problem is, but it could still be a bad meter, you could simply call the POCO and ask them to replace it and see what happens. KISS, easy stuff first.
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Ahh, but that is theft of services, even if you only used 50 cents (or less) of energy while performing your tests, every last watthour is precious:happyyes:
 
kwired said:
Ahh, but that is theft of services, even if you only used 50 cents (or less) of energy while performing your tests, every last watthour is precious:happyyes:
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Is kind of going that way, isn't it?

I think they would understand especially if you start bugging them to come out and perform the test themselves.
 
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