electrical hell #1

Things are actually progressing on the remodel. My current item of lovely joy, however, relates to our house’s electrical feed.

Last Saturday night, as I’m up late playing Ratchet and Clank: Up Your Arsenal, I notice that the lights start dimming and brightening in a weird way. Not like when the fridge turns on or the dryer starts, but worse.

As I’m a bit of a computer person, I have a few computers in the house, and a few of them are on UPSs. One of the UPSs lets me graph the voltage coming into the house; I’ve been doing this for a few years now over here. I look at the graph, and boy is it wacky. Power drops down to 105 volts from 116 volts where it usually hovers. And it flickers up and down.

But most everything seems to be okay with running at a reduced voltage, so I figure it’s just the power company doing something goofy, and ignore it for a while.

Finally at 4:30AM, I decide that it’s been going on a little too long, and call the power company to file a report, just in case it’s an actual issue. I call them, and explain to the person that the lights have been dimming funny, and that I’ve got a UPS that lets me measure the voltage, and that the voltage has been dipping down and up, and I wasn’t sure if it was an issue, but that I wanted to tell someone. So the person on the phone takes the report, and tells me that people first start going around at 6:30AM, and that she’ll pass my report onto an engineer to look at at that point.

At this point I decide to go to bed and try and get some sleep.

At 5:00AM, I get a call from someone who tries to explain to me that 117V is normal for electricity. I cut the person off and explain that I know this, and that the reason I called in is because the voltage was dipping down to 105V.

Then, at 5:30AM (this is after I finally fall asleep once), there’s a knock at the door. The dog goes nuts, of course, and I go out to the door in my underwear and open it, trying to both hold the dog back and not reveal that I’m entirely in my skivvies to the person at the door.

It turns out to be someone from the electric company who came out to look, who immediately launches into a diatribe of questions. “I’ve never seen a residential meter spinning that fast. What are you running exactly?” As I get the third degree, I get the feeling this guy must think I’m running some sort of farm inside the house. Sleepy and slightly indignant, I explain that I’m a computer person and have several computers running in the garage, as well as an electrical heater, and this is why the meter is going so fast. (Yes, my electric bills are somewhat large, unfortunately.) Somewhat satisfied with this, the engineer then explains that well, the transformer on my block was just recently replaced, and that this sort of thing can happen during christmastime with all the christmas lights and such.

(And later that day, I do some calculations to double-check, and my electrical usage is what it normally is each month; I may be using more than a ‘normal residence’, but it’s not all that much more.)

At this point I’m just tired, so all I really want to do is to go to sleep. I accept the guy’s answer, since I didn’t really have any knowledge to argue with him other than a hunch that something wasn’t right.

The power goofies, dips, spikes, and brownouts continued the next day and the next. Finally I go looking to see if I can find someone else who had this problem. For once, I put the right search terms into google, and come up with this page as the second link.

According to a few of the entries in the Mike Holt thread, the weirdness I’m experiencing might be due to a bad neutral. The way to measure this is to start at the service entrance, and measure from each phase to neutral. If the voltage on both sides is equal, it’s somewhere in the house. If the voltage on both sides is different, it’s upstream and the electric company’s problem.

This makes sense from what I remember from my Kirchoff’s Law stuff in EE classes, too; if the neutral is good, and exactly the center tap of the upstream transformer, the voltages from neutral-to-phase on each side should be +V and -V, with the neutral being at 0. If there’s a resistance in the neutral wire, it will act as a resistor, and the neutral on my side can float away from 0 up to a few volts in either direction, effectively making phase-to-neutral voltages of 105 volts on one side and 125 volts on the other.

I’ve not had to really make use of my multimeter for a long while on higher voltages — the black wire for the multimeter ended in a bare, stripped wire that I held against the one connection with my finger, which wasn’t really an option here. So after a couple of more days of these dips, I’m able to go buy a pair of new test leads, all the while hoping that the issue will be on the electric company side of things.

I go outside (it’s 45 degrees), open up the main breaker panel, and continue to hope. I take off the cover, prop up the multimeter, and hold my mag-light between my shoulder and neck like a phone. I hold the two test probes and hope one final time, and measure.

Eureka! It’s probably not my problem! I measured 122.8VAC from one phase to neutral, and 111.1VAC from the other phase to neutral. This is at the line side of the main breaker (so it’s not an issue with the breaker) and at the main neutral busbar. I can’t measure any closer to the electricity provider without breaking into the meter can, and I’m certainly not going to do that.

Just to be sure, I turned on more loads (the dips seem to get worse with more power consumption), and found 126.0VAC on one side and 107.8VAC on the other. Both times the phase-to-phase voltage stayed at 234VAC, so the issue wasn’t voltage drop on the hot lines.

So it seems like there is indeed a bad neutral between the service entrance and the local transformer. Tomorrow I’m going to call the electricity provider and ask that they send someone out to fix the issue. I’m hoping I can just explain this to them and they take care of the problem. I’ll post an update when I know more. And at some point I’ll post more on the remodel.

4 thoughts on “electrical hell #1”

  1. Ugh, I know the feeling.

    I live out in the middle of no where in England and we have to deal with a dodgy power suply. In the UK we’re supposed to sit at about 230V (“in harmony with europe”, ours goes from 225V to 240V.

    I don’t know if we have two phase into the house in the UK. All I know is it aint stable, I might have to have a look at the phases. I know the frequency isn’t stable either :/ 49.8 as opposed to 50.

    After seeing your voltage graphs a few years ago, I decided to do something similar:

    http://www.cw9.co.uk/ups/

    If ya look, have a quick gander at the last graph, it’s the view of the voltage over the past 24 hours. :/

    Doc.

  2. Yikes. I hope ours is what you said it would hopefully be, D. Doc, have you thought about using alternative power? D and I worked out that at least solar would cost more than it’d be worth, but if there was more room, wind would be tempting…

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