I get these, but frequently they are not useful. “We’re aware of a power outage” 45 minutes after it’s gone out, “it will be back in 2 hours” 30 minutes after it’s come back on, and my favorite “sorry about the outage” when it’s working fine. I appreciate the effort, but they’re not quite there yet. Fortunately outages in my area have are very rare.
I’ve guessed it is something like that, but I just don’t know.
Our cat detected this arcing, but we’ve exceeded the cat’s service life, so hopefully the Ting will detect any future events. Astute readers will notice the color of the wires, and be able to predict the likelihood of future arcing events.
When I bought my house in Arizona, I quickly noticed some odd electrical behavior (lights flickering, etc.). After some exploration, I found that I had aluminum wiring, and spent $1,500 (which was real money at the time) to have every outlet and switch terminated with CopAlum wire pigtails (the only UL-approved system at the time). The electricians saved some outlets with the wire insulation burned back and inch or so to show me. Since then, I have had no issues, but I have to insist that when I have remodeling done, the copper pigtails are not cut off to make the electrician’s job easier.
FWIW, the house across the street from me burned pretty good due to an electrical fire in the attic.
That reminds me of something that happened in one night in June. I got a txt from the power company at 8:30pm saying “your electricity will be temporarily shut off”* beginning 30 minutes later and lasting until 2am. It didn’t wind up cutting off until 9:30 and I hightailed it out of there to my parents’: it was super hot that day and I’d only just turned on the AC for the first time all summer that evening. I later got a message pushing the re-enable time to 7:30am! But I think it was on before 10:30, barely an hour. I’ve never received messages like that and assume it’s part of the smart grid they keep charging us for. The messages included the street address and a number to call the company. I live in Chicago and our power is very stable.
*I appreciate the plain talk, not a service interruption, not a click here for your message. Sign up for our app!
Traditional circuit breakers look for current overloads and short circuits. These usually originate somewhere beyond the receptacle or junction box, like inside an appliance, or a crushed extension cord. They usually don’t originate inside the walls or inside the junction boxes. Because of that, and because it is often a “hard failure,” it’s usually pretty easy to identify the culprit for a current overload or short circuit.
Arcing is more insidious and harder to troubleshoot. For one thing, it’s often intermittent. Secondly, it can occur inside junction boxes, like a copper wire under a screw head in a receptacle. Lastly, some loads have arcing under normal conditions, and AFCIs might interpret the voltage & current signatures as a “bad” arc.
Our house in Arizona was built with paper insulation in the ceiling, fire-rated for something like 5 years. After the neighbor had the attic fire, my dad went up and cleared the insulation from around the stove vent, and replaced it with glass insulation.
I just happen to be a (fairly) accomplished TDR operator, with five or six units in my possession. The problem with using a TDR is that they are very sensitive to the distance between the conductors, which shows up as a point or area of high impedance. This really complicates analysis because your typical house wiring has loads of splices and device connections where the conductors are separated from the overall sheathed cable.
I generally find high-voltage insulation testers to be more helpful. If you get one of the old-fashioned crank units, you can get a lot of satisfaction from cranking them up and seeing the needle climb, climb, climb, and then fall abruptly as you overcome the resistance.
TL;DR: TDRs (good units, not the cheap ones) are not that helpful for this purpose.
Arcing should cause a fairly distinct form of broadband electromagnetic noise. Seems like someone could build a directional antenna, or even an omnidirectional one (where you play a game of hot-and-cold), that looks for this particular kind of noise.
Intermittency would still be an issue, but a device like that could narrow faults down to particular junction boxes, etc.
Our local utility seems to be both. When someone reports an outage, it puts a little dot on the map. When the power company’s systems figure out that a particular line has gone down, it draws a polygon around the areas served by that line.
The map updates every 15 minutes.
I got VERY familiar with that map about a month ago. A nearby town blew a transformer in a substation. They shipped in a temporary replacement transformer, but they didn’t have enough power to restore service to everyone. So they tried to shift the load to another substation near where one of my sons lives. That substation overloaded and two transformers caught fire. Then they tried to shift some of the load over to the substation near me. And they overloaded that substation and one of its transformers caught fire. By trying to restore power to one small town they ended up making the outage area at least 10 times as large.
That map was very active for a couple of weeks. And I got a lot of use out of my portable generator.
I wonder if whoever decided to do the load shifting is still employed by the power company.
Did the 3rd substation burn down, fall over and then sink into the swamp?
Here in the UK I usually get a text within a few minutes of the power going off. But sometimes I get the text and my power is still on, but next doors isn’t. So they haven’t quite narrowed it down to which phase is out.
Mesa electric has a similar map but I have no idea where the data comes from. A couple years ago at about 7pm during a summer thunderstorm there was a loud crash and the lights went out. After about a half hour I called the map up on my phone and there were spots allover the city. As the evening passed they disappeared except the one in my neighborhood.
By morning the power was still out so when I took DR to work we diverted to the next block where the pole line ran. There were not only city utility trucks but also contractor trucks there and they were not only restringing the power lines but also also at least two pole transformers. Power was back about 5pm so 22 hours out all together.
They brought in a new transformer this week, and managed to screw up traffic through every town along its path for a couple of days.
They used bucket trucks to “adjust” traffic lights so that they didn’t knock them completely off of their poles, and they used special dollies to widen the trailer load across several bridges, so the transformer didn’t catch fire, fall over, and sink into the swamp creek.
Since everything went so well, I’m guessing that the folks who originally tried to route power to different substations weren’t involved in the movement of the new transformer.
