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Grounding single outlet in home

Posted by donscampin (My Page) on
Sun, Jan 2, 11 at 18:56

Can I gound one outlet (in an old home that has no ground system) by running a wire from that outlets' ground to the recently installed outside AC units' ground in it's electrical box, which is just a few feet outside the window next to the outlet?


Follow-Up Postings:

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RE: Grounding single outlet in home

Absolutely no (:

You will have to run a new cable, (hot, neutral, and ground) from the receptacle back to the electric panel.


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RE: Grounding single outlet in home

"You will have to run a new cable, (hot, neutral, and ground) from the receptacle back to the electric panel."

While not completely accurate, this is the best method.

The ONLY alternative to running a new circuit is as follows:




(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions. The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:
(1) Any accessible point on the grounding electrode system as described in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
(4) For grounded systems, the grounded service conductor within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar within the service equipment enclosure


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RE: Grounding single outlet in home

Can't accurately picture the OP's setup w.r.t. to how a 120V INterior receptacle has access to an EXterior 240V HVAC service =:O , but...

... does Code still allow that UNgrounded recep to simply be replaced with a GFCI recep, thereby addressing the safety issue, without adding a 3rd conductor?


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RE: Grounding single outlet in home

Two more layman questions:

1) Is it allowable to run a new cable from another grounded outlet. In addition to 2-wire circuits, we also have some grounded circuits for window AC's and wonder if we could tap off them for one or two nearby outlets.

2) If a two-wire outlet is supplied by BX cable, and the metal outlet box and cable are actually determined to be grounded, can a 3-prong outlet be grounded to the metal box?

Thanks.


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RE: Grounding single outlet in home

NO to both question. Petey gave the right answer. Short of running a new cable for the entire circuit, you can run a ground to one of the points in the part he posted. NONE OF THOSE rare the grounding conductor of some "other" circuit.

It matters not if that circuit is fed by a real grounding conductor (which by the way "BX" is NOT). You can't bootleg the ground off another circuit.


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RE: Grounding single outlet in home

BX was an actual type of cable a long time ago, but most of what folks describe as 'BX' is MC (Metal Clad) or AC (Armored Cable).

MC normally has a run ground wire and AC has a bonding strip that allows the armor to act as a ground conductor (BX has no bonding strip and is NOT a suitable ground).


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RE: Grounding single outlet in home

Thanks for the clarification.


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RE: Grounding single outlet in home

A lot of home things only even have a 2-wire cord, so not having the safety ground is not a big deal.

Electronics (TVs, computers. etc.) that have any type of surge protection DO need a grounded circuit to help with the protection.

In many older houses you can simply run a few new branch circuits and locate receptacles as desired for more sensitive electrical equipment.

A GFCI will protect people without a ground (better than having a ground in most cases) and that is why it is an allowed replacement for a 2-prong receptacle.

The only time a GFCI would NOT provide protection is if you are between the hot and neutral after the GFCI device AND no current leaks onto ANY other path.

Possible but not very likely.


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