OT: Power problem in my house

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dave_r_1

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I've got an older house, built in 1961, w 50A 2 phase power (2 hots, and a neutral) from the power pole.

For the past year or two, the APC UPS (battery backup power supply) has regularly been trigger, either from low or high voltage (drops down to below 90V or goes up to 140V or so), and sometimes will go back to 120V after a short time, and sometimes it'll just stay there until I turn something like a space heater on the other phase.

i finally got out a clamp-on ammeter to try to figure out what is going on.

i clamped it on each of the wires going into the house, got about 20A and 10A on the two live wires, but 0A on the neutral.
Inside the house at the main fuse box, there's the main fuse/shutoff, then all the smaller fuses below, with cables connecting the two areas.

for the two live wires, they are again 20A and 10A, but the neutral within the box is odd

neutral to power meter (power meter is between outside connection and fuse box) 3A
ground wire; 7A
neutral cable from smaller fuses to upper panel connection; 10A

these 3 wires are all screwed down together in one spot in the middle of the panel

Am I right in thinking that it shouldn't be working like this, in that somewhere between the fusebox and the power pole in the street, there is a broken connection on the neutral, and when fixed, it should carry roughly the difference between the 2 live wires and that almost no current should be going through the ground wire?
 
Your thinking is correct. The neutral should carry the difference in current. You do have a broken neutral outside your house. At least your ground is good enough to carry the current.

Call the power company to fix it.


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I had a cooked crimp connector on my neutral once, showing similar systems. When I called the PC, they were out within an hour. Seems they thought it rather urgent.

On another occasion, a limb brought down my service drop, but it only interrupted the neutral (completely) and this resulted in all sorts of electronics getting cooked throughout the house. I was home at least, and was able to rush and shut off the main. I don't know what, if anything, that saved, but I believe that when you lose your neutral, you also get a voltage change, depending on what load is on each of the two hots. Some of it may see upwards of 200 V......not good for 125 V appliances, etc.. I guess my ground was insufficient. I hadn't thought about whether it should have been able to provide a return path. Guess I was assuming it was not for that purpose and therefore would not have stabilized the voltage.

I'll second the call to the power co.....get them on it, and the sooner the better.
 
I was told by an electrician that the neutral is supposed to be grounded at the pole, so yes yours seems to be floating or poorly grounded
It's time to call the power company
Good detective work
Mark
 
Definitely not a fun way to start the week.
I've got the supplies to redo the ground on ours to a copper rod outside. Brought it all almost two years ago.
After reading Tony's reply, I'd better get on it. The ground wire is currently running over to the incoming water pipe...
 
My 100+ Y.O. house was wired in the 50's. My service came from the distribution transformer to the meter head on my barn and from there, overhead about 100 yds. to the house. They ran only the two hot wires, using the galvanized pipe running from the house to the barn for the neutral. The service was grounded to earth at the meter and at the main fuse box in the barn. At the house, ground leads were run to the cold water line and to an earth ground.
Some time in the sixties, the house to barn water line was replace with polyethylene pipe, thereby eliminating theprimary neutral return path. Any neutral current ws now through the earth. Need less to say, under certain conditions, one could get a tingle while doing dishes. The measured potential on the neutral leg could be as much as 40 volts with respect to earth. Light bulbs would glow brighter when something on the opposite leg was turned on and their life was noticeably shorter than normal.
That's all been replaced with buried service now.
 
middle.road said:
The ground wire is currently running over to the incoming water pipe...
Click to expand...
I was going to say I hope no one has redone the water pipe to PVC somewhere. Also moist ground would give better grounding in that case.
I have 2 grounds on my house, and the connection to the main power ground,
 
Up until 1986 the house I live in had two 30 amp fuse to the meter. We updated to 100 amp service on both sides doing the wiring our selves with still knob and tool wires in one run. All before I got stuck in the wheelchair. I grew up building houses we did it all. I'd say you should get some upgrades on your electric . New leads in and breaker box minimum . To much draw on light wiring causes melt down and fire. My duplex is all I have for three daughters and my wife. YUPP no fires here.
 
Just to put a cap on this, phoned the power company, they came and replaced the crimp-on connectors on the wires on each end of the power line between the house and the pole (the covers over the old ones were disintegrating), tightened the wire connections in the meter housing and may have replaced the meter itself. I asked them to check that current was flowing through the neutral, and it was, I also checked in the house, had 120V on the UPS while turning a heater on and off and no significant change for it, so the problem is fixed.

Thanks for everyone's help.
 
Nice semi-easy fix. (sort-of...)
Shouldn't deteriorate like that over 50 years. In my book. But the problem is solved!
 
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