I have several outdoor “water features”, controlled by a double paddle switches. Purely mechanical. old skool. They are behind outdoor waterproof covers. Similar to this
Twice this week, my wife was working out there and one turned on all by itself. Last night I was out there at midnight, turning off the other pumps, not standing near this switch at all, and it turned on.
I tells ya, it can freak you out!
The switch seems fine, it doesn’t feel “soft” like a broken spring or anything. So, ruling out ghosts, has anyone ever seen mechanical switches activate themselves? Or turn themselves off?
Beowulff might be on to something with debris inside the case. While it is in a weatherproof cover, it’s still outside in AZ. It’s been in service nearly 20 years. I may just replace it anyway, and not disassemble it to see.
I don’t find it that surprising. My wife and I have a couple wall switches in our house that we can turn “on” or “off” without QUITE flipping the switch entirely up or down. Closing the adjacent door roughly will sometimes cause the switch to move. Depending on the internal mechanism, I can certainly imagine a switch being “on the cusp” and then slipping one way or the other.
As far as switches failing, my grandfather once had a '56 Ford ex highway patrol car. They were in front of a restaurant at a wedding reception when the car began cranking its starter and slowly pulling out into the street (manual transmission). He ran over, popped the hood and then gave himself a pretty good burn yanking the battery cable off. In the end, the solenoid (a magnetically actuated switch) had failed.
Not sure if this has anything to do with it or not; it’s just an FYI. But standard switches are rated for 15 A, and are designed with the assumption that they’re controlling lights. If a switch is to control something other than lights (e.g. garbage disposal, power to a receptacle), I highly recommend using a switch rated for 20 A, especially if a motor is being powered.
To address all the comments: the switch is actually in the on position. So not a short (though we did check for that). Until I replace it,w e are making sure (push extra hard) that it is in the off position and so far we haven’t has a recurrence.
But that would still mean it was moving from (almost) off to on without any input. No animals, no birds, no intense ground vibrations. Still weird.
While the switch box is outdoors, it is not getting direct intense Arizona sunlight. Nothing looks distorted.
And yes there are ants there. But they have not exhibited any evidence of rapid evolution or aggressive anti-human behavior.
Ants invaded my well pump. They were crawling inside the pump relay so that the pump would not turn on. They are apparently attracted to electrical current, like the relay closing. If your switches do not close a relay, I don’t believe ants will be the cause.