electrical hell #2

So it’s time for my 3-monthly blog post. }:>

This one’ll be a follow up to my last post, electrical hell #1, in which I discover wildly different hot-to-neutral voltages on each side of the phases of my electrical service.

The next day, the power company sends an apparently normal person (who was extremely nice in comparison to the Sunday morning at 5AM person) to check things out.

This person measures at the meter and sees what I’m seeing at first, then starts tracing everything back to the transformer. At the transformer, voltages are fine. And then, when he measures back at the service entrance, voltages are fine again! The issue had gone away in the time between his measurements.

A bit befuddled, but still wanting to help, he measures a few more times but can’t find the problem. He does replace the meter, pointing out that the existing meter (with a kH of 2.7 or 3) is quite worn out and wobbly. The new meter runs more slowly, with a kH of 7 or so. (kH is the number of watt-hours of energy that pass through the meter for each turn of the big El Machino tortilla wheel.) I’m not sure whether I should be impressed or appalled that my old electric meter was worn out.

So the electric company guy heads out, I thank him, and try a couple of measurements on my own, including at the UPS. Sure enough, the issue appears to be gone.

Things go well enough for about a month, at which point the issue comes back. Once again, one leg of hot-to-neutral measures a different voltage than the other.

I finally go buy an ammeter like I’ve been wanting for a while (a Fluke T5-1000 open-jaw current tester), and measure around the two hots and neutral conductors. Sure enough, the two hot lines are carrying current, while the neutral is carrying zero.

So I try to figure out where the issue might be. I start by tightening the terminal on the neutral busbar where this wire connects. A little tweaking (the terminal won’t actually turn), and all of a sudden the neutral’s current jumps up to a real value.

Aha! I say to myself. I try and loosen and tighten this terminal, but it just won’t budge. I was to the point of worrying if forcing it would actually break it, and it still wouldn’t move.

So I sit and think about it for a minute, look closer at the terminals, and realize that the wire is actually aluminum. Yuck. (The wires inside the house are copper, thank goodness.)

I had a bit of NoAlOx, the conductive grease that you have to squirt on aluminum conductors when putting them into a terminal. So I squirt a bit of this into the terminal, tweak the screw back and forth a little more, and hope for the best.

At some point we’re going to have to replace the electrical service entrance to get rid of this issue; it seems to work OK, but it is getting old. But for now, it’s been almost two months since the voltage issue last surfaced, and if it shows up again, at least I know where exactly to go with my well-insulated screwdriver.