Sorry, yes, see my edit.
We have AFCI breakers in all bedrooms. I have never tripped one with vacuums or power tools.
My understanding is that new motors have a regular pattern that the breaker is smart enough to recognize, but old motors, with worn brushes, can have a less regular pattern and trip it.
My vacuum cleaner worked okay, my cleaning lady’s didn’t.
Certain AFCI brands/models are more prone to false trips than others. So, not only can it be particular motors, it can also be particular AFCIs that are more sensitive as well.
Unfortunately, I don’t have a list of the bad ones.
That’s an NEC requirement since somewhere around the year 2000.
GFCIs in bathrooms (and other “wet” locations) dates to the mid 1970s.
There is no requirement to retrofit them, but if your home was built after those dates, it will have them.
Motors can trip GFCIs too. Again, some brands/models are worse than others. In general, these have improved a bit over the years.
That’s the kind of situation where you do want arc-fault detection. It runs a lot of current, and if there is a wiring fault in your house wiring, it can run a high-power arc inside your walls.
While I’m here: power tools and vacuum cleaners used to have motors with commutators which used brushes and sparked at a multiple of the RPM frequency.
Modern equipment uses Brushless DC, or AC induction motors, which are not commutated, do not have brushes, and do not spark.
I think that AFCI circuit breakers will have passive, non-linear, “analog” filtering to reject one-off arcs like the arc you get every time you open a light switch. Depending on the filtering, the AFCI circuit might be more or less sensitive to old power tools and floor polishers. I imagine that different brands might react differently.
We do not use AFCI in Australia. There is less problem because there is less current. I expect that AFCI will be required for DC solar panel installations. I don’t know what the state-of-play is with that.
I never popped one of them by turning on a light, so yes, they are smart enough to ignore that.
Although there is a lot of information about digital algorithms available, and your Solar Power controller may even use some sophisticated digital arc detection system, circuit breakers in your home probably use a passive, non-linear, “analog” filtering system.
The position is just called “trip” or “tripped”. “Trip-free” is a description/property of circuit breakers, which means that the internal trip mechanism can open the circuit when a fault occurs even if the handle is unable to move for some reason. For example, it is routine to padlock fire alarm system and fire sprinkler pump circuit breakers into the “on” position so that unauthorized personnel cannot turn them off. A trip-free circuit breaker (which all modern ones are) will still be able to open the circuit on overload (like a nail shorting the conductors) even if the handle is unable to move at all.
About 2010, I was rewiring my hundred-year old house, removing knob-and-tube wiring. I had a friend who was a professional electrician and gave me lots of good advice, and I have BSEE degree and access to the code, so I was confident in my abilities.
I used AFCI breakers in the bedrooms as the code was asking for then. I had two separate circuits, each with their own AFCI breaker. One of those breakers (I’ll call it A) would occasionally trip, with nothing really on the circuit or anything turning on or off.
I finally swapped the two AFCI breakers to the other circuit, and the A breaker still kept tripping intermittently, even on the other circuit. I was confident in my wiring, and my electrician friend didn’t know what to do. I finally did an internet search on that company’s AFCI models, where I found that model and date code was under recall. I printed out that page and took the breaker and my receipt back to Home Depot, where to their credit they immediately refunded my purchase, even though it was several months after I bought them. (I returned both of them, just in case.) I bought and installed two new ones and never had a problem after that. My electrician friend congratulated me on my debugging skills, and I passed the city inspection with no issues.
I don’t like very much about Home Despot, but they are very good about returns
So it’s been nearly three weeks. What did the professionals say?
My assumption is that they simply turned the breaker fully off and back on again, at which point it stayed on because there was never actually an issue. But I’m curious if that assumption is false and there was actually an issue the electrician found.
Inquiring minds would like to know! 
The technician just came and did something to fix the lack of hot water, and now it’s hot again. And now the breaker switch is in normal position. But I don’t think he did anything to investigate what caused the switch to flip to the Tripped position to begin with. Well, it’s been 18 days and I’m still alive, so…
Well, thanks for the update!
Right.
I’ve
Count me as one. I have a room that was renovated, professionally, under permit. Even with everything turned off and unplugged in that room, we would get nuisance trips. The electrician’s response was that they get this all the time with AFCIs. I’m a pretty good amateur electrician myself, and both the electrician and I were confident we did not actually have any arcing going on. So now it’s a regular old-school breaker.
In addition to remotely tripping the breaker if the cleaning lady tried to plug in her vacuum, i also got some completely random “nuisance trips”. I was also told that that’s common.
I bought a Ting to feel a little better about returning to (mostly) old-fashioned breakers. It’s supposed to tell me if it sees arcing, etc. Of course, that doesn’t help if your house catches on fire before you can do anything about it. But I’ve now had it for several months, and so far, it’s only notified me of thunderstorms and a brief power-outage. No arcing. And my wiring seems to be in good shape.
I was a little skeptical about Ting until State Farm decided to send me one for free, covering the annual service costs as well. Big insurance companies are not known for doing things out of the goodness of their hearts, so there must be real value they see in their customers using the service.
I’m an engineer and can’t think of a way to easily make a sustained arc using typical household items outside the microwave oven that even I don’t want to mess with. Bug zapper? Hack an old CRT? Neon lamp transformer?
I’m not following you. Why would you want to create an arc? Just for fun or experiment or? Or are you questioning the need for arc fault detection as a household safety feature? Or some third thought I don’t get?
Two nails in a damp piece of wood.
This one, I think. I couldn’t make an arc if I wanted to. Being that they falsely trip a lot, what are the detection devices trying to catch?
Warm wood?