3 of 7 Preventing Electric Shock (3min:59sec)

[@guitarone71]

what about residual current circuit brekers? do they really work and prevent from electric shock?

[@bearplayz2312]

Educational video

[@bryanz5904]

Thanks, Mike. Sharing my experience, After I move to Canada from China. I designed a lighting project. If the single-phase to-ground shot current happened at the very end of the circuit, and if the fault current(back) to the breaker was smaller than the breaker's instantaneous tri current. The breaker would not trip. When the circuit length was too long, the impedance was too big to make the coming back fault current too small. So I calculated the Vd and Single-phase to Ground shot current(3-phase short current is bigger than 1-phase), then the wire should be changed even if the Vd was ok. But, when I asked my colleague, he did not support me. One suggestion: only consider the Vd. I am so confused. How about America? Really doesn't matter?

[@MikeHoltNEC]

Please post your questions to MikeHolt.Ai.

[@bryanz5904]

@@MikeHoltNEC Thank Mike, bless!

[@james77011]

At time :33 do u mean to actually turn off the circuit breaker?

[@MikeHoltNEC]

I mean having the circuit protection device automatically open during a short-circuit, ground-fault, or overload.

[@james77011]

@@MikeHoltNEC oh ok... Like having it trip?

[@MikeHoltNEC]

@@james77011 Correct

[@RekkabitesThirteen]

I thought the only way to shut off a ground fault is with a GFCI. Why do you say an overcurrent device can turn off a ground fault?

[@MikeHoltNEC]

Please watch kzbin.info/www/bejne/o6HKcol7abqqfNk (which contains parts 1 - 7).

[@d.militomilito2002]

very good explanation on how to prevent electroshock but i am confuse: why the voltage is 120v? because i see that the load is connected to Line (black) and Line (red) and therefore there must be more voltage across the load. i am right??

[@MikeHoltNEC]

The electric shock is between one hot wire and the enclosure, not between the two hot wires.