Voltage drop

[reppy007]

Can anyone remember your largest voltage drop out in the field without a loose connection or a bad connection....4-7 volts?OR more?

[Pootnaigle]

ummmmmm i had one that drops from 126 to116 here ..... the problem was there wasnt enough fault current available to blow a fuse in the event of a fault, so the voltage on that entire feeder dropped when there was a fault of anykind The corresponding phase dropped radically.

[HookinAintEasy]

We had a voltage reader on a guys meter one day.... on the other side if town we had a squirrel take out a fuse when we checked the recorded voltage from the mans house his voltage at the time of the fault dropped to 73 volts

[reppy007]

I had one which I will never forget,this was my nightmare...concerning urd...first at the house I found a difference about 4 volts between legs....at the pedestal/handhole it seemed ok...going back to the house a few minutes later one leg had close to 230 volts....the urd drops were bad and as you have now guessed ,things in the home were trashed...they were customer owned urd drops .....but weeks later the company payed for the customers drops and the things that were damaged.:nightmare:

[T-Man]

Reppy, how do the customer URD drops get energized at close to 230 volts on one leg? I'm having trouble seeing how that could happen. I can only referance the way the system I worked on is.

We owned the URD services here and a residential customer had a 120/240 volt service. I can see unbalanced load and high and low voltage but 230 is pretty high for one customer without having transformer windings screwed up which would give the same to others on that section unless this tub only had one customer. Just wondering.

[reppy007]

Well T....I have seen thousands of differences in voltage,due to bad connections,a bad neutral,ect....but this far out of balance floored me.I dont know what they did inside the home for it to change that fast.I was using a digital voltmeter,they werent new,but that was the period when I didnt trust them too well.So yea...I had to take another look,thinking that I was seeing things......the only way I can describe the feeling is that up there in my mind,it was yelling (oh $hit)....never seen that before or after.And like I said,it was a nightmare type of feeling.....but I will never forget it.:(

[T-Man]

The neutral of the service could be bad, and the ground at the residence not good either, then one phase could have gone to ground(could have been the cause of the ground burning open) then if you took a phase to ground reading on the other phase you could get a near 240 volt reading. The other phase would be a zero to ground because there would be no reference to ground or neutral. I wasn't there, just trying to figure that high voltage out.

[reppy007]

Just in case anyone is wondering,I did double check the pedestal/handhole...underload,I believe there was one other house feeding out of it...large houses..not that it made a difference....theres nothing worse,,,well I shouldnt say that...but when a guy says the drops are bad and its actually the urd secondaries it is fustrating...so I knew the urd service was bad,but getting a 4 volt difference in legs....then getting that higher voltage on one side was a first.....I refered it to a two man crew...they ran a temp bypass...costing around 100 bucks...it was then the customers job to find a electrican. Later the people called in,by that time a damage report was filled out and Downtown.....Claimes talked to me at least 3 or 4 times...saying that they were not going to pay for the damages....that should have been the end of that......but we had a dip-$hit area manager that knew nothing about linework and he winded up paying for the damaged equipment and new drops too....even though it was owned by the customer......how he paid with company money,when the people at the so called Headquarters denied it is beyond me.....now Ive seen some services with a 30 volt difference...maybe a 70 volt difference.But never a difference like that one....Its one of those experiences that you would have to go through to fully understand....even if you dont understand....but I wouldnt wish that on anybody...except..... kidding :D.

[Orgnizdlbr]

Open neutral, one bad leg, large appliance on at the house hogging load, absolutely can read voltage like that on one leg. No city water ground, bad house ground, bad recipe. Had some plumbers killed here replacing cu water services when they cut the pipe, bad house grounds......

[T-Man]

Yea Org, I was thinking a water heater

[thrasher]

Tman not sure I was reading you right. I have always seen the big unbalanced voltages with a bad/open neutral and no 240 volt loads running. Usually if the there was a 240volt load the legs came back closer to balanced. When we look for a bad neutral I usually have the consumer turn-off their 240 breakers and then ask them to turn on the microwave with a cup of water inside. That tends to show a bad neutral.

[reppy007]

Open neutral, one bad leg, large appliance on at the house hogging load, absolutely can read voltage like that on one leg. No city water ground, bad house ground, bad recipe. Had some plumbers killed here replacing cu water services when they cut the pipe, bad house grounds......

I bet that happens more than we think,back in the 70s I had some type of reitive that went under a home that was built on blocks,wooden house..He was trying to repair a plumbing issue.He also was electrocuted I assume by the pipes.....I wonder who has the job of crawling under a home like that to investigate....would most even know of the hazards even when looking right at it?

[reppy007]

Tman not sure I was reading you right. I have always seen the big unbalanced voltages with a bad/open neutral and no 240 volt loads running. Usually if the there was a 240volt load the legs came back closer to balanced. When we look for a bad neutral I usually have the consumer turn-off their 240 breakers and then ask them to turn on the microwave with a cup of water inside. That tends to show a bad neutral.

Microwaves have worked good for me too,or an iron, which I never cared for.....

[reppy007]

I will add this much.....when a lineman gets 230 volts on one leg....the thought of checking the other leg never occurs.:nightmare:

[T-Man]

That's right Thrasher. A bad neut will give imbalance. I'm just trying to figure out how the one leg with 230 volts occurs as Reppy states.


Reppy did where did you test to get the reading? In the breaker panel? Or meter socket?

[reppy007]

Its been so long ago T....Im not 100% sure now....If I were to guess it would have been @ the breaker panel.The question Ive asked myself is why the voltage went berzerk at the time when I was there....or its possible that the trashed equipment was trashed before I arrived.I cant see why it would happen at that moment if their was a neutral problem before I arrived.The occupants never said much......their daughter did.And Im sure she was the one that kept calling the service center area manager....bugging him until he understood that paying up would be the only way to stop her from calling and calling and calling.

[reppy007]

The 230 figure is high....Very high....but thats what the voltmeter read.And thats when my eyes were good....not that they are bad now...just not as good.

[T-Man]

Tman not sure I was reading you right. I have always seen the big unbalanced voltages with a bad/open neutral and no 240 volt loads running. Usually if the there was a 240volt load the legs came back closer to balanced. When we look for a bad neutral I usually have the consumer turn-off their 240 breakers and then ask them to turn on the microwave with a cup of water inside. That tends to show a bad neutral.

That's right unbalance load indicates a bad neutral. I was just wondering how one leg could be almost phase to phase voltage. How and where was the test made. There was indication the service was bad. . . .burned open? Neutral open? You need both phase legs to get voltage above 120 readings.

[reppy007]

I can only speak for this area....is it ground conditions...bad ground rod connections...not enough ground rods @ the house installed/deep enough...ect...People will sometimes say to check amps on your ground rod if there is a neutral problem.I understand that and have checked before....and there has been many of those befores....only a few times did I get any amps .....In this area most overhead service is feeding older homes,and pipes can serve as a ground also. With underground,the homes are newer.and the pipes are pvc...if that underground neutral goes south....from my experiences....the ground rods helped very little if any.....time after time I have seen burned up equipment on those types of services.....as far as the answer to as how the voltage can be that high on one leg....I can just say that without the neutral....it can go out of control/no telling/the skys the limit.

[Divemaster]

Approximately 90+% of the residential services in our territory are burried. We've seen 200+ volts phase to ground at residences that had a bad neutral before. Variables like soil types, moisture, and grounding all make each one different. I personally don't like digital multimeters for trouble shooting (a low battery can waste your time and have you chasing a ghost). I still like my old Simpson, it hasn't lied to me yet!

[reppy007]

Hey Dive....did you see that program a couple of weeks ago on people free diving,going 400ft-500 ft under without any tanks....they say its becoming popular.

[Divemaster]

No I didn't but hopefully I'll catch it in the future. Something I would've done 20 years ago.