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#167605 - 08/16/07 07:48 AM Over/Under voltage problems  
kenny2656  Offline
Junior Member
Joined: Mar 2004
Posts: 7
lake charles, la usa
Customer with serious over /under voltage problems .Local POCO has been less than helpful.Customer wants me to try to solve the problem.This is a residence-600 amp single phase service (3) 200 amp main breakers) 50KW generator w/auto transfer switch.The problem is the incoming voltage (240)gets out of balance example:(phase a =180 vac to ground, phase b =60 vac to ground. We know its a POCO problem, because when the customer has problems, others within a 2 block area have the same problem.I am considering installing a voltage relay with over/under voltage adjustments connected to a capacitor trip device connected to shunt trip main breakers.Has anyone here tried anything like this?
Opinions welcomed.


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#167611 - 08/16/07 11:21 AM Re: Over/Under voltage problems [Re: kenny2656]  
earlydean  Offline
Member
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
Sounds like classic open neutral.


Earl

#167619 - 08/16/07 04:15 PM Re: Over/Under voltage problems [Re: kenny2656]  
mxslick  Offline
Member
Joined: Oct 2004
Posts: 803
Atomic City, ID USA
Originally Posted by kenny2656
Customer with serious over /under voltage problems .Local POCO has been less than helpful.Customer wants me to try to solve the problem.This is a residence-600 amp single phase service (3) 200 amp main breakers) 50KW generator w/auto transfer switch.The problem is the incoming voltage (240)gets out of balance example:(phase a =180 vac to ground, phase b =60 vac to ground. We know its a POCO problem, because when the customer has problems, others within a 2 block area have the same problem.I am considering installing a voltage relay with over/under voltage adjustments connected to a capacitor trip device connected to shunt trip main breakers.Has anyone here tried anything like this?
Opinions welcomed.


Sir, don't waste your time or the customer's money rigging up any fancy stuff. DEMAND that the POCO get their trouble guys out to find that open neutral before your client's house and the others go up in flames...you may also want to have the others experiencing problems also jump on the POCO about it.

This situation is very dangerous..let us know the outcome...


#167624 - 08/16/07 06:01 PM Re: Over/Under voltage problems [Re: mxslick]  
techie  Offline
Member
Joined: May 2005
Posts: 246
palo alto, ca usa
If the local POCO drags their heels, invoke the magic words
"Public Utilities Commission" (or equivalent for your state). If they still drag their heels, file a complaint with the PUC.


#167625 - 08/16/07 06:15 PM Re: Over/Under voltage problems [Re: techie]  
techie  Offline
Member
Joined: May 2005
Posts: 246
palo alto, ca usa


#167627 - 08/16/07 06:23 PM Re: Over/Under voltage problems [Re: techie]  
RODALCO  Offline
Member
Joined: Dec 2005
Posts: 854
Titirangi, Akld, New Zealand
That is an open neutral problem there and can cause fires.
Most appliances, lights, TV's, electronic eq. don't like it and will burn out.

Demand that the POCO checks it's connections, at the TX, cables, and also the meter terminals.

Then the cables and terminations to the main distribution board have to be checked by the electrician (yourself).


The product of rotation, excitation and flux produces electricty.

#167631 - 08/16/07 06:53 PM Re: Over/Under voltage problems [Re: RODALCO]  
Rewired  Offline
Member
Joined: Jan 2006
Posts: 558
Hamilton, Ontario, Canada
Hust for ha'-ha's, what is the voltage line- line when this happens? if its steady at 240 then its almost guaranteed its a bad neutral.
My former employer had a problem identical to this. the problem was found to be a bad connection between right at the transformer bushing... One thing that tipped it off was we did an amprobe check at the main ground where it connects to the water line, zero amps was flowing.. If it were to have been a break elsewhere in the neutral you might see current flowing in the ground, taking a path through the water piping in the street then back through another ground in another building or through some other path back to the center-tap bushing of the transformer...

A.D


#167674 - 08/17/07 04:56 PM Re: Over/Under voltage problems [Re: Rewired]  
kenny2656  Offline
Junior Member
Joined: Mar 2004
Posts: 7
lake charles, la usa
Thanks for the replies. We have already determined the neutral problem is the fault of the POCO, but it has to be happening somehow on the primary side because many transformers are involved. They claim to be working on the problem.My customer is is not willing to wait for them to fix it.He wants protection on his side of the meter. Money is not a big issue, results are.


#167706 - 08/18/07 07:46 AM Re: Over/Under voltage problems [Re: kenny2656]  
Obsaleet  Offline
Member
Joined: Apr 2003
Posts: 362
Pa
I would contact the POCO and give them 24hrs to straighten it out, or I call the PUC. I would also contact the nieghboring homes/business and urge them to contact POCO. Make lots of noise about the situation! Remind them if any equipment gets damaged you have instucted everyone concerned to call there insurance co. and lawyer up.


Choose your customers, don't let them choose you.

#167708 - 08/18/07 12:09 PM Re: Over/Under voltage problems [Re: Obsaleet]  
George  Offline
Member
Joined: Feb 2002
Posts: 375
Often a problem takes a while to fix.

---

I guess the Power Company could disconnect power until they find the problem.


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