bad neutral help

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Praedatus1

Praedatus1

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Portland, Oregon
i need to know if someone else can confirm this test:

I find, on a service call, bad voltages when a 120v load is put on either phase: 200v phase A, 40v phase B... I know I have a bad neutral, so I brainstorm and since I only have a meter I perform this test:

I plug in a hairdryer at the washer outlet, (unplugging all electronic stuff), turn it on, which immediately changes the voltages at the panel (the hairdryer running at 40v, I didnt want to destroy it with phase A 200v) and then RUN outside, up a ladder, and test the overhead wires at the drip loop: bad voltages here too.

So, my question:

If my neutral was bad in the house (say in a crawlspace j-box or something) would the voltages be correct at the drop and then "change" at the fault?

PS as it turns out, I was right and it was a bad transformer at the pole, which PGE changed that day
 
Praedatus1 said:
If my neutral was bad in the house (say in a crawlspace j-box or something) would the voltages be correct at the drop and then "change" at the fault?
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No, the break must be on the line side of wherever you read the imbalance.

PS as it turns out, I was right and it was a bad transformer at the pole, which PGE changed that day
Click to expand...
See? ;)
 
maybe im not asking it right.
I know why it measured bad in my scenario, but lets say the fault was NOT in the xformer, but rather a bad splice in some crappy j-box in the crawl. Would I read good voltage outside all the way up to the fault and then bad voltage from there into the panel?

I cant tell if the 1st response answered this.
 
except that when I remove the 120v loads, the voltage goes back to normal. Although I see your point: I could pull the meter, tap in a pigtail outlet off line side meterbase, and try 120v load there (hairdryers work good for that sort of thing, Im sure all of you know). That is probably the best "basic" test. Poor people blew up 2 computers over 1 weekend.
 
Praedatus1 said:
(hairdryers work good for that sort of thing, Im sure all of you know). That is probably the best "basic" test.
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I've never used a hair dryer for that.

Did those folks lose one computer. Then got an other one and said, hey lets try this one, too.
Hmmm. They should have used the hair dryer. It seems more durable.
 
well i think one was regular desktop, the other was laptop, but i told them *maybe* *hopefully* just the transformer/converter went out for the laptop (but probably not).
It sucks because it can happen to anyone. My $2900 65" 1080i samsung baby could go up in smoke. I would cry like a baby.

Its funny how PGE argues with me *every* time, and this is the third one I've found in 8 months. Two underground neutrals went bad, and this xformer. They had to dig up one guy's prize flowerbed.
 
buckofdurham said:
I've never used a hair dryer for that.

Did those folks lose one computer. Then got an other one and said, hey lets try this one, too.
Hmmm. They should have used the hair dryer. It seems more durable.
Click to expand...


Don't laugh I had a guy with an open neutral blow up 3 tvs in a row, the first one blew so he got the one from the bedroom and plugged it in it blew then he gets a third one from the kid's room, plugs it into the living room, it blew. Must've been a damn good game on.
Then he noticed the refrigerator was sounding weird so he called me.
 
Praedatus1 said:
I know why it measured bad in my scenario, but lets say the fault was NOT in the xformer, but rather a bad splice in some crappy j-box in the crawl. Would I read good voltage outside all the way up to the fault and then bad voltage from there into the panel?
Click to expand...
No, you'd read good voltage from the transformer to the meter to the panel to the J-box, and bad voltage beyond that point. The line side of the problem reads right; lhe load side reads wrong.

Your last question almost sounds like you mean a crappy J-box in the service cable, between the meter and the panel. If so, then the meter would read right but the panel would read wrong.
 
I don't have a hair dryer, nor does the wife, but not a bad test load. I usually use a few of my own 500w halogen shop lights. (I think I have only had one ever blow during a hi/lo, and the bulb cost a few bucks) I find it best NEVER to use any customer anything as a load - next thing you know that hair dryer is some sort of family airloom once it has melted Salvador Dali style into a puddle on the priceless carpet. Or worse, go into a dead short while doing so, melting premis wiring insulation in the same way.

FYI - a great way to fry GFI's and AFCI's is to have them even in the panel during a hi/lo.
 
Praedatus1 said:
well i think one was regular desktop, the other was laptop, but i told them *maybe* *hopefully* just the transformer/converter went out for the laptop (but probably not).
It sucks because it can happen to anyone. My $2900 65" 1080i samsung baby could go up in smoke. I would cry like a baby.

Its funny how PGE argues with me *every* time, and this is the third one I've found in 8 months. Two underground neutrals went bad, and this xformer. They had to dig up one guy's prize flowerbed.
Click to expand...

They need to go after the poco for the damages along with your bill.
 
Jim W in Tampa said:
They need to go after the poco for the damages along with your bill.
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I agree. Most (all?) electric utilities have a Claims Department for just that reason. Call them to get their forms, fill them out and provide documentation. You may get some argument but most will respond favorably if you prove your case. They will have records of the situation and even what crew was there and who took the call (which was probably recorded) from the person who called to report the imbalance. :smile:
 
thanks I will let them know. Esp. thanks LarryFine, you always seem to have the answer (but thx to everyone else too). I carry my own hairdryer 1875 watts of testing power!
 
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