Ground wire size

Old 03-28-04, 07:37 AM
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Ground wire size

I am in Chicago where it is customary to use EMT conduit that also serves as the ground.

As an extra precaution, I have thought about grounding my receptacles & switches to the metal boxes.

My question is this:

Since my circuits are already grounded via the conduit, if I also use a ground wire does it need to match the size wire used on the circuit? Primarily, on my 20 amp circuits that use #12 wire can I get away with #14 wire for the ground?

I already have #14 green wire.

Would this pose a hazard?

Old 03-28-04, 02:20 PM
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Yes, you could have a hazard develop.

Let's say that the conduit becomes dosconnected somewhere along the way. The circuit will remain grounded because of the wire you add. That's a good thing. However, any current that does flow on that ground wire will flow only on that ground wire, instead of being split between the ground wire and the conduit.

Spend the few dollars for a roll of 12 gauge wires and do it right, or don't do it at all.
Old 03-28-04, 05:55 PM
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20A circuits require #12 CU ground.
Code requires the switches and receptacles be connected to the metal boxes.

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