Extentions from ungrounded receptacle circuits

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steve66

steve66

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Illinois
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Engineer
Did the NEC ever allow the addition of 120V, 15 or 20A grounded receptacles to a ungrounded receptacle circuit without providing a ground connection?

In other words, an existing 120V circuit with 2 prong receptacles was extended. But the new receptacles were 3 prong, and the ground prong was just left unconnected.

If this was ever allowed, then my understanding is that it should be allowed to remain. If not, then the 3 prong outlets would have to be replaced with 2 prong outlets, or a ground would have to be provided.

Thanks:
Steve
 
rcarroll said:
To my knowledge, it was never allowed. You do have the option of installing 3 prong receps on a 2 wire system if they are GFI protected.
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Good question. I thought I remembered something like GFCI receptacles without a ground, but I can't find it now. I've been looking in 250.130(C). I just had another thought. If the original receptacle was fed with EMT, could the new receptacles just be grounded by connecting to the original metal receptacle box? (The extension was done with wiremold, and the original receptacle was feed within a masonary wall, so I didn't get a chance to look at the feeder conduit.)

Steve
 
OK, I found it now. 406.3 (3). It looks like you are right. A grounding receptacle can be fed with an ungrounded circuit from a GFCI if the receptacle is labeled "GFCI protected", and "no ground".

Steve
 
Steve,

My recollection is, that the only way the receptacle EGC terminal could be left disconnected from some form of an EGC was if GFCI protection was provided for such a receptacle. Cold water pipes might be used, in lieu of an EGC, until the early '90s.

Before GFCI protection, for extensions as you describe, one either installed two-prong receptacles or one added an EGC or a connection to a cold water pipe.
 
406.3(D) used to be in 210.7 in the 1999 and earlier, right on back to 1962.
 
Extentions from ungrounded receptical circuits

Extentions from ungrounded receptical circuits

250.130(c)
 
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