Need to change 2 prong outlet to 3 prong outlet

[Dr. Ugs]

High all!
Great little forum. Hopefully you can help me out with a little problem i got.

Recently bought a house and the room ill be using as a living room has only one outlet(that aint the problem), problem is, its a 2 prong ungrounded outlet. All my entertainment toys are 3 prong plugs....(they all hook up to a surge protector power bar(which has 3 prongs as well)

How can i put in a 3 prong outlet if i got nothing to hook the ground to?? I've been reading about GCPI outlets and im confused, tired as hell(been working all day at house), can someone help me out?

[kactuskid]

In order to install a 3 prong receptacle you must have a ground in the box, otherwise you can install a GFCI receptacle. This will provide a 3 prong plug but still will not provide a ground.

Though before you do that you should check to make sure whether a ground exist or not. If the cable that supplies power to the receptacle box is armored cable then a ground may exist in the box. To tell you need to buy a neon bulb voltage tester or a multimeter. You measure between the hot wire and the metal box. If you get either 120 volts or a light on the tester then this indicates a ground is present in the box. Then you can install a 3 prong self grounding receptacle in place of the 2 prong. Self grounding recpetacles are sold at Home Depot and indicated on the box to be self grounding.

Your other option is to run a new circuit to the living room that has a ground and install a new receptacle.

Here's a link that'll explain all of this to you and under what conditions you can replace a 2 prong with a 3 prong.

http://www.codecheck.com/250_50_commentary.html

[HayZee518]

kactus - all well n good on the site but the mention of the grounding screw "at the back of the box" it's a green hex shaped head screw [10-32] NOT 8-32 as they say!

[LazyPup]

Someone correct me if I am wrong, but if the existing outlet is not wired with armored cable and they cannot get a ground you can install a GFCI for safety reasons, because the GFCI will automatically switch off if there is an unbalanced amp load from power to common, however, this circuit is being used for electronic entertainment equipment. While the GFCI would provide safety it cannot provide a necessary ground path for the electronic white noise filters in the circuit, which means you would still have problems with static or ghost imagining. In my humble opinion, if the circuit is not wired with armored cable or another suitable means of effecting a ground, the proper solution would be to pull a new circuit from the panel.

[kactuskid]

You're correct LazyPup, a GFCI would provide the means to connect to but that's about it, installing a new grounded circuit would be the best way to go with lots of electronics. To protect an ungrounded circuit from a surge there are Mode 1 surge suppressors that you can buy, these dump to the neutral instead of ground. They're more expensive but would provide for the needed protection. Or a whole house surge suppressor can be installed in the main panel.

[Dr. Ugs]

high all and thx for all the suggestions/ideas.

i went back today to work on house. and check my outlet.It's a 2 prong outlet but its got a ground already wired to it. Simple as it gets.

Thx again guys.....

[kactuskid]

Wierd that a 2 prong would be installed, so before just installing a 3 prong receptacle you need to verify that the ground is good then by taking a voltage measurement like explained above.

[mabr1827]

What can happen if you replace 2 prong outlets with 3 prong outlets wired with bx without a ground wire? If the box is grounded because of the bx, is attaching the new outlet to the box sufficient grounding, or do I have to install some type of ground wire from the outlet to the box?
Thanks,
Confused DIYer

[kactuskid]

If yu verify that the box is grounded by the bx cable then you can install a self grounding receptacle and no ground wire from the receptacle to the box is needed. These are specially marked on the box to be self grounding and are different than a cheapo receptacle. You can find them at Home Depot. Make sure that it has the gold spring clip on the yoke where the screws go through. You'll see one on the receptacle pictured below.

[HayZee518]

This is all well and good IF the receptacle has an intimate contact with the box if it's metal. The ground path shall NOT rely on the 6-32 screw for a ground! Most likely the receptacle is floating above the box about an eighth to 3/16" and NOT in intimate contact with the box.
IF the box is grounded through the BX armor, then it is better to use a ground pigtail with a screw in the 10-32 tapped hole.