[lb1lf]

-During the annual EE safety refresher course I take at work, the instructor makes a point of the fact that during domestic work, the electric shock is often merely the trigger for the real injury; you get zapped, then fall from the ladder you were on or whatever.

(We have 240VAC mains, but I guess an unexpected jolt of 110VAC would be sufficient to make me jump...)

[Klathmon]

I was messing with some DIY generator wiring when I was younger and ended up getting a bite from 110.

My hand was in a shitty position kind of around a table leg, and the shock caused me to clamp down with my hand and kind of "chokehold" the table leg. It took me a lot longer than I thought it would to even register what was happening, and then to kind of throw myself away. I'd been shocked before, but this just kept going after I realized that it was happening and I just didn't know how to process it.

I ended up with some nasty burns on my hand, a really sore whole arm, and a scary realization of how it could have been a lot worse if just one or 2 things were slightly different.

[jjeaff]

110v or 240v will kill you dead where you stand. But it's not really about the voltage. The higher the voltage, the easier it is for the electricity to ground out through you. But it only takes a few milli-amps across the heart to kill you. A household line can deliver 10-20 amps.

Luckily, human skin is not highly conductive and neither are rubber soled shoes.

So if you are taking proper precautions and not kneeling on a wet floor while using all metal tools on bare wires when someone flips a breaker back on, then your risk is rather minimal.

[michaelt]

> 110v or 240v will kill you dead where you stand.

In my experience, when encouraging people to follow safety rules you get better results with true examples that justify the rules than with exaggeration like this. If you tell a person one thing they know isn't true, they're liable to start thinking the other things you tell them aren't true.

240v might kill you if you're up a ladder, elderly, have an undiagnosed health condition, or are just plain unlucky. But it's not the guaranteed instant death that, say a 25kV shock is.

[dsfyu404ed]

>In my experience, when encouraging people to follow safety rules you get better results with true examples that justify the rules than with exaggeration like this. If you tell a person one thing they know isn't true, they're liable to start thinking the other things you tell them aren't true.

As someone who comes from a compliance/human factors background I absolutely hate internet discussions of safety. They are chock full of people exaggerating everything for up-votes/likes/virtue points and while within a given community that may increase compliance it is the exact wrong way to increase compliance from people who are working under a different set of incentives.

[jjeaff]

>guaranteed instant death that, say a 25kV shock is

Also not true.

You can safely hold a metal rod into the air as a 20,000 volt tesla coil fires lightening bolts through the air and into your body then to the ground, because the coil is built in such a way to induce very little amperage across your body.

My point being, it's not just the voltage.

I was just imprecise with my language. What I should have said is "110v or 240v could kill you dead". And that is why the following sentences qualify what I was saying.

Household voltage is plenty to kill you, assuming the factors are aligned.

I have been shocked multiple times with household 110v and it was not pleasant at times and others it was barely a twinge. It all depends on how well you are grounded.

I had a very unpleasant shock once from a 12v car battery because I was sitting on the ground in shorts and fiddling with it somehow.

[ttsda]

It's impossible for a 240V outlet to deliver 10A through your body. Unless you're made of metal or something.

[jjeaff]

But you don't need 10Amps to kill you. Just a few hundred milli-amps is enough to kill a human.

[duckymcduckface]

Think the point is that the voltage won't collapse under the load.

[taneq]

Exactly, you can get zapped by tens of thousands of volts from a van de Graf generator and be fine, and you can die from 110V mains. The difference is the importance of the supply.

[LeifCarrotson]

I was working with a circular saw and extension cord on a ladder in light rain Monday night (gotta get that roof up before snow settles in!) and got a moderately bad hit of 110. I didn't drop dead where I stood nor was I thrown off the ladder. Don't exaggerate.

I did retire the extension cord, though.

[jjeaff]

You misunderstand my comment. And you misunderstand how electricity works. Had you been well grounded, you could have easily died. It only takes about 200 milliamps to kill a human.

110v/10amps is plenty to kill you. It's not the voltage that kills you, it's the amps. That is why you can touch a 20,000 volt tesla coil and barely feel a tingle.

[6nf]

> But it only takes a few milli-amps across the heart to kill you. A household line can deliver 10-20 amps.

10-20 amps? Not across your skin!

Usually a 220V zap at home won't cause instant death.

[wlesieutre]

That's the point made in the line after your quote

> Luckily, human skin is not highly conductive and neither are rubber soled shoes.

Could also note that depending on your circuit breakers, a short circuit will continue delivering higher than its 20A rated capacity for some time until the overcurrent protection goes off.

Thermal breakers won't react as quickly to overcurrent as thermal magnetic breakers, so it depends on what kind of protective equipment is installed.

EDIT: some reference on circuit breakers https://www.se.com/ww/resources/sites/SCHNEIDER_ELECTRIC/con...

> For example: based on the curve on page 3, an iC60 circuit breaker of curve C, 20 A rating, will interrupt a current of 100 A (5 times the rated current In) in: 0.45 seconds at least, 6 seconds at most.

6 seconds is a pretty good chunk of time for a 20A circuit to happily be delivering 100A of current.

[jjeaff]

You should read the whole comment before contradicting someone. It really wasn't that long of a post.