Is is safe to only use a gfci with no ground wires downstream?


Tester101 nailed the question, so I'll cover another option.

Depending on your situation, it is often possible to retrofit ground. Normally, wires in a circuit must be kept together for good reason. Ground is a special case, it can be routed separately from the other wires in a retrofit situation.

That is because ground is not used to flow current except in a fault condition (when a breaker is about to trip). The job of the ground is to give a nice easy path for the fault current to flow back to the service panel (breaker box) and trip the breaker, without passing through any humans or setting anything on fire.

Does a GFCI make an ungrounded circuit safe? The GFCI is comparing the current on "hot" and "neutral". If they are the same, all the current is accounted for, and none of it is shocking anyone. The issue is whether the GFCI is precise enough to detect a dangerous current - this varies. 10ma is enough to knock someone out, and that is fatal in some...

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What you have done was recently made legal under NEC 2014.

The only hitch is that a 20A circuit requires 12 AWG ground wire. So if the circuits were 20A, they are now 15A.

A ground is nothing but a safety shield. No appliance should be flowing current to ground, not even the GFCI.

You may have already had a ground fault

If a device flows current to ground and the ground is not hooked up, it will "float" the ground to a potentially hazardous voltage, energizing whatever part of your grounding system does exist, e.g. Chassis of equipment, coverplate screws on outlets, etc. However no current will flow unless there's a path back to source.

Suppose you already a GFCI in such a situation? Since no current is flowing, it would not trip a GFCI. This is safe because if you did get shocked, then current would be flowing and the GFCI would trip.

By adding the ground, you created the path back to source, which is assuring that the GFCI...

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I got shocked.

It was over 10 years ago but I still remember the jolting feeling.

If you’ve seen Back to the Future you probably know how Doc Brown got his white hair.

Well I felt how he looked.

Why is this so dangerous? It’s simple: the human heart has electrical impulses and that rhythm, if interrupted, can be deadly – especially for children.

Certain rooms in your house are required to have GFCI outlets so that you won’t be shocked.

Knowing where they need to be and how to install them can save you a ton of dough. And allow you to sleep a lot better at night.

GFCIs are required by electrical code (I’m talking about the states here) in bathrooms, kitchens, outdoor spaces, and in garages.

These are places where moisture creates electrical hazards and you need protection.

Why all this hubbub over an outlet?

Here’s the deal, GFCI’s detect even the tiniest leak in electrical current, and they immediately shut off...

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