GFCI question

Say you wanted to replace an existing duplex receptacle with a GFCI outlet. You open the box and there are three romex type cables, 2@ 12/2 and 1@ 12/3. The red of the 12/3 is connected to the ungrounded conductor of one of the romex type wire and is not desired to be protected by the GFIC protector… All neutral(3) are connected as of course the grounds. The remaining two ungrounded conductors are connected. The receptacle was wired with pigtails and has been ignored for clarity. What is done with the white (grounded) conductor from the 12/3 when wiring a GFCI?

Why wouldn’t it be terminated with the other neutrals?

The red is probably a switch leg for a light but that is not the only possibility.

Consult an electrician.

Red leg on the 12/3 is a through circuit. No electricians?

Why not post this question in the electrical section where Robert Meier and Jim Port hang out? They are wealth of knowledge and both are electricians I believe.

Make sure that you know what you are working with and what you are doing. You could be dealing with a switch loop or a multi-wired circuit. If it’s a multi-wired circuit there should be 240V between the red and black conductors and the grounded conductor is shared by both (it carries the difference in load between the two circuits).

This needs to be fixed by an electrician too many variables to know what is needed .
On site examination is needed to make sure of a proper installation.

This needs to be fixed by an electrician too many variables to know what is needed .
On site examination is needed to make sure of a proper installation.

Since the old receptacle is pigtailed you just remove it and connect the white and black pigtails to the GFCI device.

but there are three grounded (white) and two ungrounded (black) conductors. Two white and two black are typical, it’s the third white from the 12/3 through circuit that has me stumped. Guess I won’t put a GFCI there. The outlet is 5’8" from the kitchen sink fixture, think the buyer’s inspector will ding it?

Not sure I understand the problem, you can’t just remove the old receptacle and reconnect the black and white pigtails onto the new GFCI receptacle? Are you trying to protect downstream receptacles as well?

Maybe I am reading this wrong but it sounds to me like you have split receptacles with a shared neutral. If that is the case you cannot install a GFCI receptacle or breaker. Get an electrician to verify this.

Upon visual inspection of this receptacle box I deduce this:

Two circuits enter the box, the ie:12/3. I’ve used 12/3 before to supply two different circuits, so I didn’t have to run two different 12/2 conductors on a long run. This is cool as long as you don’t connect them in phase at the distribution panel.

One circuit I want to protect by GFCI (including the duplex outlet I removed) and those downstream aka: load outlets although the load outlets do not need to be GFCI protected.

So…I have two black(ungrounded), line and load (typical). But then I have 3 grounded (line, load, and the continuing circuit) common white wire.

Like I said previously, hope the buyers’ inspector doesn’t jack me up for having a non GFCI outlet within 6’ of kitchen sink fixture.

The neutral needs to be pigtailed on a MWBC. It cannot rely on the device.

I’ll work in reverse, if the receptacle serves the kitchen countertop it requires GFCI protection regardless of it’s proximity to the sink.

You have a box with three cables:

  1. 12/3 which supplies two circuits
  2. 12/2 which feeds other receptacles on one circuit and contains the new GFCI receptacle
  3. 12/2 which feeds something on the second circuit, GFCI protection not required

The neutral from cable #1 gets spliced with the neutral from cable #3 and pigtailed, pigtail goes to the LINE side of the GFCI.

One hot conductor from cable #1 goes to LINE side of GFCI the other gets spliced to the hot conductor in cable #3.

Cable #2 (black and white) connects to the LOAD side of the GFCI receptacle.

Thanks Robert, I did a mock up.

You need a load neutral.

I thought so too but on second look it’s there.