Two wire outlet need three wires for new outlet


Old 09-26-05, 09:56 AM
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Two wire outlet need three wires for new outlet

Old house and want to add an outlet in bedroom. Existing outlet only contains two wires.
Can I add a three (grounded) outlet to this old two wire outlet?
Or do I have to locate a three wire (grounded) outlet to tap into?
Or do I have to get rid of the two wire in the old outlets with three wire (grounded)?

I am sure this question has been asked many times, but I have not been able to locate past thread.

Any help would be great.
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Old 09-26-05, 10:05 AM
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You may not extend an ungrounded circuit to add a new receptacle. However, you may replace an existing two-hole receptacle with a three-hole receptacle in two cases only: (1) You have or provide grounding all the way back to the electrical panel, or (2) you replace the receptacle with a GFCI receptacle.

Which of these you might want to do depends on why you want (need?) to replace the receptacle. What do you intend to plug in here?

Note: There's a lot more on this subject, but let's start slowly until we understand more about what you are doing.
Old 09-26-05, 10:08 AM
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What you are talking about is grounding. Here are the basics:

You cannot extend an ungrounded, two-wire circuit. If you remodel any part of an old ungrounded circuit, the whole circuit must be brought up to code by rewiring it with 3 conductor cable. The best course of action with ungrounded circuits is to leave them be.

The best thing for owners of old homes to do is to add new grounded circuits in the rooms or areas where you need more power. Taping into existing grounded circuits is troublesome, because older homes typically only have grounded outlets in the bathrooms and kitchens. Neither of those circuits can be legally extended outside the bathroom or kitchen.

Therefore, the best thing you can do to get grounded receptacles is to install a new "home run" circuit from your breaker/fuse box and use that to power three prong receptacles where you need them.

It is legal, by code to replace two prong receptacles with three prong receptacles if the circuit has GFCI protection and you place the "NO EQUIPMENT GROUND" and "GFCI PROTECTED" stickers on the affected receptacles. This provides protection from electrocution, but does not provide the grounding required for computers or other machinery that requires a ground.
Old 09-26-05, 10:28 AM
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Thanks for the information!!
It is an upstairs bedroom and only has one outlet.
All the upstairs outlets are two prong, actually all the upstairs lights and outlets are on one circuit.

I guess this leads down the path of rewire the upstairs. Maybe I should call an electrician.
Old 09-26-05, 10:31 AM
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"existing outlet has only 2 wires"-----

The presence or absence of a Grounding path depends on the Wiring Method used to route the conductors between outlet-points.

It's possible the W-M is Armored Cable, which is a "metallic" type of cable fastened to metallic boxes. this is best determined by the type of outlet-box, and the type of cables that extend from the fuse/C-B panel to the interior outlets.

If you determine that the W-M is Armored Cable, you can test & measure the resistance of the Grounding-path between to outlet and the "source",i.e, the panel where the fuse/C-B for the circuit is located.

Good Luck & Learn & Enjoy from the Experience!!!!!

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