Green wire

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jwax
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Green wire

Post by jwax » Tue Apr 21, 2020 4:29 pm

Maybe too much time on my hands, but.....
In house wiring, why is the Green wire usually the same gauge as the current-carrying wires?
The green should never have current, right? So why don't they save copper and make it a smaller gauge?

dyarker
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Re: Green wire

Post by dyarker » Tue Apr 21, 2020 4:58 pm

The green wire is never supposed to have current. But it is there to protect you from problems like hot coming into contact with metal case of appliance. Then it needs to be at least same size as hot to carry current to ground.

Smaller could cause dangerous voltage on case. If really small it could burn out before breaker trips, leaving full line voltage on case.

For those reasons (and maybe more) it is in the building code in most areas.

Cheers,
Dale Y

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jwax
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Re: Green wire

Post by jwax » Wed Apr 22, 2020 5:03 am

Makes sense dyarker! Thanks!

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dacflyer
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Re: Green wire

Post by dacflyer » Wed Apr 29, 2020 7:28 am

in my house i have some old wire, where the ground is thinner than the mains.. I do not know the reason of this back then,, but all house wiring grounds is the same size now days..

but for reasons ( usually leakage) , there is some current on the ground conductor, like milliamps, usually a low reading.
to find it, you usually need to check circuit or see if it goes away when unplugging an appliances.
Start at the ground of your house , then breaker box, then work your way in...

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haklesup
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Re: Green wire

Post by haklesup » Tue Jun 09, 2020 3:57 pm

older codes allowed for cheaper wire including the notorious Copper - aluminum

Think of the safety ground like a safety rope, when climbing a mountain, one does not want the safety line to be a string, if needed it will do all that the main rope is called upon and more.

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