A month or so after C & L arrived and we wired the studio for an outdoor kitchenette, they reported that one of the four duplex sockets we put in had failed. Naturally, it was the one that was powering their refrigerator, so food was lost.
This is strange to begin with. Usually, problems with electrical systems manifest right away (during initial testing) or within a day or two. If stuff works for a few weeks, chances are it will continue to work until it hits senescent failure (old age). Working fine, then failing after a month, is pretty unusual.
It turned out that the GFCI had tripped. Permanently. That’s frustrating, in that it was brand new, but those things are mass-produced and sell for quite low prices (about $6) so it isn’t too disappointing, but still a hassle.
I had another new-in-box GFCI in the parts bin, so we put it in. It worked when we wired it up and tested it, so we buttoned up the box and then… it failed. We opened the box again, and I noticed that one of three wires in a wirenut appeared loose. We tightened it up, tested again, and it now worked. Thinking that might have been the only problem (though the symptoms didn’t really fit), we put the original GFCI in but it was still broken. Back to the replacement, which still worked. Then I put a multimeter on it, and it read 83 volts. What. The. Heck. The meter got the same reading at other sockets, which all tested fine. Maybe the power was failing under load? So I plugged in the toaster oven that they’d been using, but it wouldn’t even turn on. Everything else, though, was working fine.
I went back up to the garage and got my backup multimeter, which I had used only a week earlier when the electric gate batteries failed. Its battery was dead. It was in a rubber case, which was so old that it was nearly impossible to remove. I had to use some special tools to get it off. I opened the meter and replaced the battery, but the meter would only flash some numbers for about half a second every time I turned it on, and was otherwise dead.
I was dubious, but everything seemed to be working correctly, even other high-draw cooking appliances we plugged in. So we decided to just keep an eye on it.
Two days later, that duplex outlet died again, as did the other one in the same outlet box. We opened the box again, and the wirenut that had come loose before was now melted. I re-wired the box without using any splices, and everything came to life and has been working fine since. But it’s kind of weird that we had these failures all at once:
- a brand-new GFCI
- a high-end multimeter
- a replacement multimeter is on its way
- a toaster oven
- the toaster oven is waiting on my new workbench to be dismantled and diagnosed
- a wirenut
- a low-cost backup multimeter
I have no reason to think these might have been cascade failures (for example, the bad wirenut somehow causing the GFCI to fail). It was just a pretty darned bizarre coincidence.
—2p