Negative Pf residential Home

[Rock86]

Issue is still on going. Many developments, but no problems solved.

I would like to share with everyone... I went for the first and actually got hands on with the house. After everything, i had measured values of the following...
L1 22.6A, L2 22.1A, N 5.0A. This does not make sense to me.

I checked for continuity between every neutral and EGC, and neutral to other neutrals. Found the dryer was wired incorrectly, so i fixed that. Nothing other than that.

Any ideas?

 

[ptonsparky]

Issue is still on going. Many developments, but no problems solved.

I would like to share with everyone... I went for the first and actually got hands on with the house. After everything, i had measured values of the following...
L1 22.6A, L2 22.1A, N 5.0A. This does not make sense to me.

I checked for continuity between every neutral and EGC, and neutral to other neutrals. Found the dryer was wired incorrectly, so i fixed that. Nothing other than that.

Any ideas?

5 amp on the neutral indicates you may have flow from a neighbor that shares a transformer with you. I will need to go back and reread.

 

[Joethemechanic]

5 amp on the neutral indicates you may have flow from a neighbor that shares a transformer with you. I will need to go back and reread.

Maybe a neighbor who has an open or high impedance neutral. Some of the neighbor's neutral current could be flowing on the water service or some other bonded shared utility. Maybe amp clamp all the grounds and bonding conductors??

 

[ptonsparky]

Apparently I've reread it several times now.

OP: Shut the main off and amp clamp your neutral and all GECs. Are there other customer owned buildings or loads on the property? Cycle them until you can find the source of the that neutral current. It could be nearby POCO lines but you need to verify that you or customer is not the issue.

 

[Rock86]

5 amp on the neutral indicates you may have flow from a neighbor that shares a transformer with you. I will need to go back and reread.

I told the guy in the beginning that it was most likely utility related. His utility company came out and put a metering device on their meter but never gave them the results.

 

[Rock86]

Apparently I've reread it several times now.

OP: Shut the main off and amp clamp your neutral and all GECs. Are there other customer owned buildings or loads on the property? Cycle them until you can find the source of the that neutral current. It could be nearby POCO lines but you need to verify that you or customer is not the issue.

Its a residential single family. The utility company had to 6 people on a transformer when he moved in, and then changed it to 2 homes on one pot.

 

[ptonsparky]

Its a residential single family. The utility company had to 6 people on a transformer when he moved in, and then changed it to 2 homes on one pot.

Community based water service with metallic lines?

 

[Joethemechanic]

Its a residential single family. The utility company had to 6 people on a transformer when he moved in, and then changed it to 2 homes on one pot.

Pots all have their secondary neutrals connected to the MGN

 

[Rock86]

Community based water service with metallic lines?

Well water.

 

[gar]

230627-0920 EDT

If you have a center tapped single phase transformer with the same magnitude load current on each half of the secondary this does not mean the neutral current is ZERO. No other connections to the secondary. Think about this to figure out why the neutral current may not be ZERO.

To work on analyzing this problem look for either a voltage or current variation on your power wires that is sufficient to sync the scope from the change. Try to sync on a current variation that appears to link with the light variation. At this sync point look at how both voltage and current vary. Then what do you have to do to make a change.

..

 

[ptonsparky]

You neutral current should be close to zero. 5 amps, IMO, is not.

 

[Rick 0920]

Maybe the house was built on an Indian burial ground.

 

[gar]

230627-1031 EDT

ptonsparky:

I would agree with no other information, but one can not rule out any particular problem without more information..

.

 

[Rock86]

230627-1031 EDT

ptonsparky:

I would agree with no other information, but one can not rule out any particular problem without more information..

.

I would love to give you more information, but its a single family dwelling unit, not a hotel in Vegas . I do not know how exactly the electrician wired between each device, but from what I am reading at the panels, I cannot find a discrepancy. That does not mean one does not exist within walls.... but from the various tests i have performed, I can't find an issue which would cause 5A extra on the neutral.

If the system was un balanced say 30A on L1, and 15A on L2, sure 15A on the neutral back to the source would be acceptable, but that is not what we are getting.

"When you have eliminated the impossible, whatever remains, however improbable, must be the truth." I'm going with its just magic

 

[tortuga]

Co-worker has been complaining that the lights in his newly built house keep flickering. He has had the utility company out there, 3 or 4 electricians, and has asked us EEs in the office what could cause it.

What kind of lights and how many circuits are involved?

 

[tortuga]

Also does the power company use TWACS metering by chance?

 

[Joethemechanic]

If you kill the main breaker, is there still current on the neutral?

 

[zbang]

Count another as "Find that current". Might take a lot of metering around- GEC, all bonding jumpers, utility neutral, each branch circuit, etc; anything you can fit a meter around, get a reading and log it.

Be quite careful when you disconnect things, with 5 amps flowing there have to be at least a little voltage involved.

 

[ptonsparky]

How good are your bifocals? (5. Or .5)

 

[gar]

230627-1226 EDT

Lets go back to light flickering. On a incandescent it takes several volts change at 120 V to see much flicker.

So go to a remote outlet some place. Connect a digital meter to the outlet, use a 3 1/2 dight meter on about a 200 range. You will be able to read 0.1 V changes.

Plug the meter into an outlet. Then switch a 1500 W 120 V heater on and off at this outlet. What is the voltage change? Next replace the meter with a 15 W 120 V bulb. Now how much does the bulb appear to flash? Put the digital meter on the phase line that the heater is on at the main panel on the incoming main service wire. How much is the voltage change at this point?

Report back.

.l