Open ground 2 wire receptacle

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Philxx
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Open ground 2 wire receptacle

Post by Philxx » Sun Sep 08, 2019 12:09 am

Hi: We have a last in line 2 wire receptacle with 3 prongs and no ground wire. The old receptacle failed and when we tried to install a new 3 prong one it displays an open ground. I checked and the metal box is grounded. So should I run a green wire pigtail from the new 3 prong receptacle to the box and attach with a screw or is there a better solution? The upstream boxes do not display open grounds.

Thanks for your help.

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emtnut
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Re: Open ground 2 wire receptacle

Post by emtnut » Sun Sep 08, 2019 7:34 am

Philxx wrote:
Sun Sep 08, 2019 12:09 am
Hi: We have a last in line 2 wire receptacle with 3 prongs and no ground wire. The old receptacle failed and when we tried to install a new 3 prong one it displays an open ground. I checked and the metal box is grounded. So should I run a green wire pigtail from the new 3 prong receptacle to the box and attach with a screw or is there a better solution? The upstream boxes do not display open grounds.

Thanks for your help.
If you have a multimeter, you could measure from the hot to the box to verify if the ground is in fact connected.
If not, either use a self grounding receptacle, or the pig tail as you suggested. If you still show an open ground, then try to find what feeds this receptacle, and verify the ground is intact, and continuous on to the next box.
~~ Ford Ford Ford Ford Ford Ford :mrgreen: ~~

Philxx
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Re: Open ground 2 wire receptacle

Post by Philxx » Sun Sep 08, 2019 10:06 am

Hi: Thanks for your comment; I do not know much about electrical matters so I am not sure how a self grounding receptcacle works and I did a quick search and found several listed that are 15 amp whereas this box is on a 20 amp breaker. Could you give me a specific part no or product that would work in my case? Also I am assuming that when I get 120 v from the hot to the box that the box is grounded - is that correct?

Thanks

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Aaron
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Re: Open ground 2 wire receptacle

Post by Aaron » Sun Sep 08, 2019 10:37 am

Yes, your box should be grounded if you're reading 120V from the hot lead to the box. It's because your boxes have armoured cable connected to then from the panel, or straight steel conduit tubing, and thus is the source of your ground continuity.

All receptacles are "self-grounding" to the extent that the mounting bracket, called a yoke, makes metal-to-metal contact with the metal box when you screw it in. Just make sure that you remove the little plastic or paper screw-retainer first.

Receptacles that "self-ground" as an advertised feature don't use those little plastic or paper screw retainers so they are guaranteed to self-ground without any step of removing them.

In any case or in doubt, a ground bonding pigtail can be used between the back of the box and the ground screw of the receptacle.

Philxx
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Re: Open ground 2 wire receptacle

Post by Philxx » Sun Sep 08, 2019 10:46 am

Great; so I just need a 20 amp receptacle remove the screw retainers and make sure the yoke is in contact with the box and I should be OK correct?

Thanks

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Aaron
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Re: Open ground 2 wire receptacle

Post by Aaron » Sun Sep 08, 2019 1:52 pm

Yes, if it's a 20 amp circuit with 12 gauge wiring, then you can use a 20 amp receptacle.

Test the ground prong of the receptacle after you fastened to the box, and if it tests with a ground then you're all set.

Philxx
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Re: Open ground 2 wire receptacle

Post by Philxx » Sun Sep 08, 2019 2:18 pm

Will do; thanks very much.

Philxx
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Re: Open ground 2 wire receptacle

Post by Philxx » Sun Sep 08, 2019 2:30 pm

Just realized 20 amp receptacles have a t shaped plug which wont work for my washer which has the usual 3 prong plug; so am I ok using a 15 amp receptacle and then testing as you suggest

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Aaron
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Re: Open ground 2 wire receptacle

Post by Aaron » Sun Sep 08, 2019 2:57 pm

The 15 amp plug from your washer will plug in just fine to 20 amp receptacle. So connect whatever receptacle you have on hand, you could use 15 or 20.

A 20 amp plug actually has the sideways neutral prong, that's why a 20 amp receptacle has a T-shaped socket.

Philxx
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Re: Open ground 2 wire receptacle

Post by Philxx » Sun Sep 08, 2019 9:24 pm

OK thanks very much for your help; much appreciated

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