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enter image description hereenter image description hereWhat is this wire for? The picture shows a wire connected to the grounding screw and back to the outlet. Is this commonly done to get a connection to the metal box? My outlet tester shows this outlet as wired correctly and grounded.

This is in the kitchen and I would like to swap the pictured outlet for a GFCI outlet. Can I still add a GFCI outlet without a grounding wire? The box is metal and is connected to a metal conduit in the back.

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    Can you post a photo clearly showing the back of the box in question please? Aug 29 '20 at 22:15
  • First instinctive response is that's totally FUBAR... Somebody was trying to make a "grounded" outlet where there was no ground. But, wait for the electricians to chime in.
    – FreeMan
    Aug 29 '20 at 22:17
  • Can you measure the voltage between the red and black wires? Aug 30 '20 at 1:11
  • I don't have the tool to measure the voltage between the red and black wires. Aug 30 '20 at 3:16
  • Where were the red and black wire connected? Were they on the same side of the outlet or was one on the side with the bootleg wire?
    – DoxyLover
    Aug 30 '20 at 5:25
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That is what is called a “bootleg ground” and it’s both against code and dangerous. This can be done when there is no ground in the box. It works because the ground and neutral are connected back in the main panel. However, there are problems, such as if the neutral wire back to the panel fails, suddenly, the outlet ground is at 120 volts (through the load, out the neutral pin, through the wire to the ground pin.

The interesting thing is that it appears that the wires are going through conduit which should provide a good ground to the metal box.

Assuming that the box is indeed grounded, all you need is to install a “self grounding” GFCI.

On the other hand, if the box is not grounded, what you must do is install a GFCI, leaving the ground screw disconnected. Also, label the front of the outlet “no ground”. There should be a label in the packaging that you can stick on.

A GFCI is the only legal way to install a 3-prong outlet on an ungrounded circuit.

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    Actually I suspect a bootleg neutral, since the only wires coming in are red and black. Which is really sketchy, for the same reasons, but even moreso. If neutral is running on red or black, still sketchy as bleep.
    – Ecnerwal
    Aug 29 '20 at 23:25
  • Do I need a grounding pigtail to install the self-grounding GFCI? Aug 30 '20 at 3:19
  • @humboldthiker The whole idea of a self-grounding outlet is that it positively connects its ground to the box without a wire.
    – DoxyLover
    Aug 30 '20 at 5:22
  • A "self-grounding" GFCI won't be enough since the box contains no neutral at all. Neutral is literally missing from the pipe. The installer skipped neutral and used ground (the pipe skin) for neutral. A GFCI could only work if it did exactly the same thing. Aug 30 '20 at 13:53
  • @harper The OP just confirmed that one of the wires was connected to the neutral (and bootleg ground) of the outlet. The crimes were (1) using a non white wire for neutral and (2) bootlegging the ground when the box is probably already grounded. I guess the original “electrician” ran out of white?
    – DoxyLover
    Aug 30 '20 at 17:17
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Neutral is not ground. Neutral carries normal operating current. Ground is just a safety shield, and can't carry current if it's to do its job. Back at the service panel is a neutral-ground equipotential bond meant to keep all the conductors near ground (not floating at 4000V due to a transformer leak), and to provide a return path for fault current. Failure to understand this bond leads many to believe neutral and ground are interchangeable. Not so.

Bringing lazy to a whole new level

This is a metal conduit wiring method, where the metal pipe carries the ground for you. Easy peasy, ground is done! But this person was so lazy they couldn’t even be bothered bringing a (or a proper color) neutral wire.

Just throw a neutral wire in the pipe

Since it's conduit, it's easy to add wires. Pull a real neutral wire into that pipe (or if separate circuits, 1 neutral per circuit; remember gray is a legal neutral color, my roll of grey wire is my favorite one!) Wire it properly then remove that jumper.

Noting that in a multi-wire branch circuit (MWBC), it is normal for 2 hots to share 1 neutral. Since this setup has no neutrals at all, you get to decide which is an MWBC. Make sure to follow the MWBC rules.

And you'll probably need to do this on every recep, lamp, disposal, dryer, range, and every other 120V load on the premises.

... And test

Lastly, check out each of your circuits by plugging small loads (night lights, etc.) into each circuit, and installing a GFCI breaker on one circuit at a time. You need to have > 10ma (1.2 watt) load on each circuit so you can detect crossed neutrals.

For MWBCs and 240V loads, you can use a 1-pole GFCI breaker and simply land both hots on the breaker hot screw. Temporarily, for testing; it MUST be undone right after testing, especially on MWBCs.

Or, you can use a 2-pole GFCI breaker, and when testing 120V circuits simply leave one hot screw unused. That will let you fully test 240V and MWBC circuits.

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    Read the OP answer to my latest question. One of the wires was connected to the neutral side of the outlet. There is a neutral wire, it’s just not white. One of the wires, probably the red is connected to the neutral.
    – DoxyLover
    Aug 30 '20 at 17:14

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