I pretty much had the same thing happen in my garage. This is a farm,
I have a main disconnect on a pole,and have numerous triplex cables
overhead going to different buildings. One of the connectors on a
secondary pole corroded on the neutral. Tthat feeds the garage and
one of the barns. I learned of the problem when I walked in the
garage and plugged in a small electric hand drill. The drill was
really slow. After screwing around with it, I decided the drill was
dying and went to get another one from the back room. That room is
dark so I flipped on the lights. They were real dim. That's when I
realized there might be an electrical problem. I took that drill to
the house and it worked fine. I went back to the garage and plugged
it into another outlet. As soon as I turned it on, those dim lights
in the back room got real bright, and a few seconds later they went
out (they were CFL bulbs). thats when something smelled hot, and I
found smoke around one of those CFL bulbs. I shot off the switch to
those lights and got my test meter. I got odd votages all over the
garage. I flipped on a light on another breaker and it flashed and
burned out immediately. At that same time the radio in there which
always comes on when I turn on the lights, got real loud, then quit.
I flipped on my 240V welder and it worked fine. At the same time I
noticed the outdoor flood light came on. With the welder on, I
flipped on soem more lights and they all worked normally. When I shut
off the welder some lights got real dim, others real bright.
Suspecting the neutral, I got a 100ft spool of #12 wire and ran it
from the neutral bar at the main disconnect to the neutral bar in the
garage box. Everything measured out perfectly, but most lightbulbs
were burned out, as well as the radio. The drill worked fine. But at
the same time, the barn had no power at all. Sure enough, the neutral
connector cables were all corroded up on the pole. Someone had used a
splitbolt labelled for copper wire, and used it on the aluminum
triplex. Thus it corroded. While I was up there I redid all the
connections, and replaced all the split bolts because they were all
the wrong type. Everything has been fine since, I lost 5 CFL bulbs,
one flood light outside, several more standard bulbs and my radio. A
vent fan in the barn died a few days later so I suspect the motor got
zapped with 220 and weakened it.
On Thu, 26 Jun 2008 19:00:48 -0500, "S. Barker"
Post by S. BarkerI can answer this with experience. A long long time ago, (about 1987) we
experience some weird happenings with our lights and whole house fan. The
whole house fan is what tipped us off to the problem initially. It all of a
sudden just slowed down. Some lights were bright, some were dim. The TV
would not come on. After poking around a bit, i got out the (analog) meter
and found some outlets had about 80 volts and others had about 144. Then,
some how, i had the brilliant idea of turning on the oven. When i turned
the oven on, the fan went back to normal, the lights normal. The 240v load
apparently balanced the system. I was at somewhat of a loss at that point.
I was not near as experience in electrical things at that time. I called an
electrician friend of mine, he came down, poked around in the box some and
decided to loosen the ground on the buss. "OH! GUESS WHAT? Fire on the
ground" he said. I'm like "what's that mean"?. He said "well even though
i've never seen this before, it sure looks like an open neutral. So i get
on the horn with the power company. FYI, it was Kansas City Power and
Light. They come out, and basically look at what i'm experiencing and the
first thing the guy does is pull the meter. Then he measures the voltages
on the incoming legs. All is equal. Then he tells me the problem must be
on the inside. Puts the meter back in and the imbalance returns. "yep , he
says, problem is on your side". So at this point, i'm at wits end, not
knowing what to do, so I calls the fire dept and they say 'do you have a
fire'? I says no, but I will, if someone does not fix this power imbalance.
So that prompts a little higher level of action from KCPL, and they come out
again. The service guy makes all his checks and then talks on the radio for
a while. His supervisor says "you know that sounds like an open neutral".
The guy comes back and says they suspect an open neutral. At that point, I
explode. I said "NO SHIT SHERLOCK" I told you guys that 3 hours ago. They
ran a bare wire from my meter can to the service box on the street and lo
and behold, all becomes normal again. (did i mention i have underground
service?) They came out the next day and started digging. About a foot
from my water meter, at a depth of about 16" the neutral wire was corroded
clean in half. Apparently it had been nicked by the backhoe putting in the
water line 10 year prior. Well anyway, they fixed the wire, and all was
good for exactly a year to the day. It was so weird, one year later, HALF
the stuff in the house quit working. I had a dead leg. When they came out,
i explained what had happened the year before and so they dug again. Sure
enough, about 2 feet from the neutral problem, one of the hot legs had
corroded in half.
Well anyway, that's my long and drawn out story of an open neutral. I
forgot to mention, I took all the documents from the open neutral service
down to the KCPL office in downtown KC, Missouri and collected a check for
one TV and 2 VCRs. They were fried.
steve barker
Post by BillI've seen "loose neutral" connections on electric service panels, but
never a fully disconnected neutral with the two hots remaining connected.
So I was wondering what exactly would happen if a residential electric
service (3 wire 240/120 with neutral) lost just the electric company
neutral connection but had a good ground to the neutral bar in the main
panel?
Would current flow to the ground connection?
If the load was not balanced between the two hots (only every other
breaker in use at the time [extreme situation]), could the ground wire
potentially carry say the full amperage of one of the hots?
Or in other words, should the ground wire in the main electric panel be
sized to carry the full load of one leg of the service should this
situation happen?