[throwaway0a5e]

>Touching the circuit breaker handles on the service panel is a "competent adults, paying close attention, only at need" activity.

Kindly screw off with the FUD peddling.

You should be able to flip breakers all you want without doing anything more than annoying people by interrupting whatever those breakers were powering.

A breaker panel is designed so that you need to get out a screwdriver and remove fasteners to get near anything that might hurt you.

Unless someone is actively working on a circuit <insert a bunch of low effort comments about the virtues of lock out tag out here> you shouldn't be able to hurt anyone or anything by flipping a breaker on or off. Breakers protect the wires. Devices are responsible for their own protection. Incomplete circuits get capped to prevent shorts to ground or elsewhere.

[serf]

>A breaker panel is designed so that you need to get out a screwdriver and remove fasteners to get near anything that might hurt you.

you hope.

zinsco breaker panel boxes are still commonplace in the united states on older properties; they require no fasteners to open up and are (mostly) bussed in such a way that they're extraordinarily dangerous when open.

Still, I agree with the spirit of your message -- but let's be clear, household electrics are dangerous, and not every breaker panel is going to be designed with safety in mind.

[galangalalgol]

Two of the last three houses I've lived in had front panels that no longer fit, so you needed to take care when operating the breakers. In the older one, we tripped a breaker and about half the lights in the house went out. I went hunting for it and eventually went to flip off the main to start a more thorough check, only to find that is what had tripped, leaving half the house on... About half my 120 and all my 240 breakers were wired direct to the bus bypassing main. I'd love to hear a pro's stories. I bet they see really weird and terrible stuff.

[quesera]

FWIW: Poorly-fitting panel covers would never pass an inspection and are inherently dangerous. It's really important for the panel to be enclosed. Humidity, dust, vermin, and fingers get in. Sparks get out. Your home insurance would be worthless in case of a fire. Never mind the risk to irreplaceables.

But re: tripping the main -- this is likely a fault in the breaker itself. It's not likely that a faulty line breaker allowed enough current to trip the mains breaker (though it does happen, but see below). Of course several overloaded lines can trip the mains, but this is exceedingly rare. A fault in the mains breaker is a serious problem for sure. However, unless you inspected the wiring yourself, I'd hesitate to assume that it was miswired as you describe.

In standard US residential service, you get two 120V lines ("legs"). If the mains breaker failed, it's possible to lose one of those legs to the buss that supplies the line breakers (and the house fixtures), while the other leg stays up and powering the "other half" of the house. In this case, 240V appliances will appear to be "out" because they are only getting partial power (240V is really just two 120V services, 180degrees out of phase).

So I'd guess the cause was a failed/fatigued mains breaker. That's a job for an electrician, regardless, who would surely notice miswiring if present, and the other code violations that you definitely had.

[galangalalgol]

The inspector did fail it, and has failed every house I've ever had inspected. The inspectors for my buyers also failed it. People just kind of live with it on old houses. Never thought about it making an insurance claim fail. So the main breaker only turns off one leg? Why wouldn't you have one for each.

[quesera]

The mains breaker controls both legs, but they are separately protected. So if a protection sensor fails, it might only interrupt one leg. The switch controls both legs though.

I've done a lot of electrical work in old houses, but only in big cities where a failing inspection is just not tolerated. I've seen old country homes where regulation is ... less strict. This might not be an urban/rural divide, but that's my experience having lived in both.

I'm amazed that you were able to buy or sell a house that did not pass inspection. If the buyer was financing, the mortgage would require insurance, which would require inspection. In a cash sale, the buyer should be sophisticated enough to take responsibility for the repairs.

I think (in my high-regulation states) it's actually not legal to sell a house that does not pass a safety inspection. At least not without surrendering the certificate of occupancy until repairs are completed and inspected.

[galangalalgol]

These houses have all been in the DFW metroplex, so low regulation TX. The people that bought the terrifying breakerbox had a first time homeowner loan and the lender complained about some of the vegetation being too close to the house, but somehow the box was ok. I turned the main breaker on and back off, and half the lights were still in. Weird one. All the outlets that had a ground hole were actually grounded, most of my friends have houses with fake grounds, knob and tube or worse, aluminum wiring. Regulations are sometimes a good thing. Its probably why our houses are cheaper though.

[mindslight]

Couldn't it also be a really old style of panel without a singular main breaker, either falling under the "rule of 6" or perhaps dating from before it?

[quesera]

Some Zinsco panels do require fasteners.

The faultiness of Zinsco panels are not a special concern with flipping the breakers. They're just faulty. And you don't even need to open them to be dangerous, they have corrosion and heating problems.

> not every breaker panel is going to be designed with safety in mind.

Well, to be fair -- of course they were designed with safety in mind. They just failed.

But yes, replace any Zinsco panels! Also some Federal Pacific and Challenger/GTE-Sylvania panels. This should be caught in a home inspect, and most home insurance companies will make it a requirement of coverage.

[bell-cot]

At small scale, either living alone or with a few other responsible adults, you're pretty much correct.

But you've never had grandkids who got interested in playing with the breaker panel, have you? Nor almost gotten yourself electrocuted, when you trusted a "not quite so sharp as they once were" older relative to turn off the specific 20A circuit that you were working on?

Also worth noting - residential circuit breakers, even new (vs. decades-old plastic that's getting kinda brittle) are often rated for vastly fewer on/off cycles than even the crappiest old wall-mounted light switch.

[Ensorceled]

I agree, kids and senile seniors should be kept away from the breaker panel.

But that wasn't your original assertion, stop moving the goal posts.

[quesera]

Well, if you're working on the wires, lightswitches can be just as dangerous as breaker panels.

Don't ask incompetent electricians to help you with electrical work. Check!

[rootusrootus]

> lightswitches can be just as dangerous as breaker panels

That's very much not the case. A light switch, at least in the US, is just 120V. Sure, it could kill you, but 99.999% of the time it'll just annoy you if you touch the hot wire inadvertently. You can easily get 240V inside the panel, however, and on top of that you can easily get it at 200A. I'm a lot more careful when I've got the panel cover off for any reason.

[tlb]

There isn't 240V to ground, which is the usual path for shocks. To get 240V through your body, you'd need to touch two hot wires at the same time. And you feel it when you touch the first one, so I think this is rare. You should be working with one hand most of the time.

The 200A is a danger. A direct short from a bus bar to ground can peak at 1000s of amps before the main breaker blows.

[quesera]

True, and of course it only takes a small fraction of one amp to cause harm to a human, if the path of the current crosses your heart or lungs.

240V at 200A would burn you crispy, but it's a bit challenging to get to.

120V at a fraction of 1A can disrupt/stop your heart, and it's easy to get inside a service panel.

[quesera]

OK, but no one is talking about working on the inside of panels.

It's been clear throughout the thread, but yes -- don't open breaker panels and work on them casually.

Flipping a breaker in a closed, code-compliant panel is exactly as safe as flipping a lightswitch in a closed, code-compliant wall box.

[rootusrootus]

> OK, but no one is talking about working on the inside of panels.

I must have misunderstood, then -- you said light switch wiring is as dangerous as breakers, and breaker wiring can only be found inside the panel.

[quesera]

It won't be particularly rewarding, but if you go back through the history you will see the full context.

It involves the safety of requesting an inexperienced person to flip breakers.