Sunday, December 19

Flickering lights, loose neutral, unbalanced power

I post this in hopes that it's indexed into the interwebs by Google and the like and it might be found by someone else who needs the information.

Over the last several days the power in the house had been flickering when appliances came on.  We had gotten used to the slight momentary dimming when the furnace or the fridge came on.  On Friday it got much worse.  The lights would get dim and really bright, sometimes rapidly for seconds at a time.  At one point it was like the house lights were like a strobe light going dim then bright repeatedly for 10 seconds or so.

I did my best to test and debug.  I did some research on the internet and dreamt of the problem all Friday night (when I actually could sleep).  On Saturday I put a couple other projects to the side so I could concentrate on the power.  I had to run to town to get a new volt meter, the last cheapy I bought stopped working.  I was shutting off various circuits to see if I could isolate if a single appliance was causing the problem.  I shut off the circuits to the water heater, the furnace, the refrigerator, the deep freeze, in various permutations but the problem continued.

I called a friend who has done some electrical work for us recently (that's another story, remember: cable rated for direct burial doesn't mean it's rated for rock), but he couldn't make it until Saturday afternoon.  I went on with other projects having exhausted my knowledge.

When John did arrive, he did his best to test it all out.  We were seeing unbalanced power in the breaker box of the house. We were expecting to see about 125 volts from each phase of the hot wire compared to the neutral, but we were seeing wide and changing ranges.

We moved to the main breaker under the meter on the pole.  We opened it up and saw the neutral lug was literally glowing hot!  We shut the power off immediately, the area around the lug had started to discolor and a mounting screw had welded it self to the fixture.  We let it cool and shut off various circuits in the house and the barn to try and determine what was going on.  During our testing we were seeing that there was 10 volts from the box to the neutral.  You should expect to see no voltage between the box and the neutral.  In laymens terms, the box it self had a charge and could shock you...  not good.

John tested the voltage on each leg of the hot wires and saw that each phase was moving from at lowest 13 volts to 130 plus at the highest.  Also not good.  We consulted with his trade-school electrician teacher and some research I had done on the internet and it pointed to a loose neutral on the power company's side of the equation.

After about 3 hours of waiting in the dark with no heat the on-call line crew of Southwest Electric Co-op showed up and fixed the problem.  They replaced the neutral from meter to the box and tightened everything down.

The lights no longer dim even when a space heater or the furnace is turned on.

Jennifer and I slept so much better last night.

3 comments: said...

Three hours isn't so bad - you could be waiting days some places! I'm glad it is all fixed. Good debugging by your sparky.

Teresa said...

That is so scary! Glad you got things figured out and fixed. Glad to know you are still alive and well! Have a Happy New Year!

Duane Keys said...

wobbly: no three hours wasn't so bad in the whole scheme of things! :)

Teresa, we're sill kicking, hope you have a happy new year as well!