Under my sink is 1 non gfi receptacle that controls dishwasher and garbage disposal. I want to put 1 gfi receptacle to replace current one. There are only 3 wires – one black one white and one red. This is a stand alone outlet and will not power any other outlets. How would these 3 wires connect to the outlet?
Electrical – 2 circuits on 1 gfi receptacle
electricalkitchens
Related Solutions
First things first, here's a link to Leviton's 7299 combination switch & GFCI instruction sheet. For a tamper proof it will be a T7299. The only reason I give Leviton is because I know the part number. Hubbell, GE or Cooper are just as good and make the same.
GFCI protection for both outlets.
Follow the instructions that come with the GFCI. There are leads for the switch and lugs for the GFCI and also the feedthru-protection of another receptacle.
No GFCI outlet behind the dishwasher (for easy resetting without dishwasher removal).
This is accomplished by feeding the dishwasher receptacle using the GFCI feedthru-protection lugs.
The switch only toggling the garbage disposal outlet and not the dishwasher outlet.
This is accomplished by using the leads on the combo switch & GFCI to feed the garbage disposal.
Am I going to need to run some more wire through the walls?
If there are no wires between the combo switch & GFCI then you will have to pull some romex between the two.
Should I investigate adding a GFCI breaker for that circuit?
The breaker will cost a lot more than the combo switch & GFCI. Also, if the GFCI trips then you have to go to the breaker to reset it. At least with the GFCI receptacle feeding your dishwasher receptacle, you will be closer.
What other solutions would achieve the same effect as listed above?
I think this is the way to go, so you don't have to pull your dishwasher out to reset the GFCI. The nice thing about this site is some of the people either can think out of the box or have faced this problem before.
If you're using 12/3 with ground, non-metallic sheathed cable from the panel to the outlet, you'll have no problem doing what you want.
Materials:
- 20 ampere double pole combination GFCI circuit breaker.
- 20 ampere duplex receptacle.
- Length of 12/3 with ground non-metallic sheathed cable.
- 20 ampere single pole single throw switch.
- 2x single gang boxes.
Procedure:
Pull the cable
- Install a length of 12/3 cable between the switch box and the receptacle box.
- Install a length of 12/3 cable between the receptacle box and the service panel.
Install the switch
- Connect the Bare/Green grounding conductor to the Green grounding screw on the switch.
- Connect the Red ungrounded (hot) conductor to the common switching terminals on the switch.
- Connect the Black ungrounded (hot) conductor to the switched terminal on the switch.
- Use a twist-on wire connectors rated for use with a single 12 AWG conductor to cap off the grounded (neutral) conductor.
- Tuck all the wires into the box, and mount the switch.
Install the receptacle
- Clip the tab connecting the upper and lower receptacles on the ungrounded (hot) side of the duplex receptacle.
- Connect the Bare/Green grounding conductor to the Green grounding screw on the receptacle, and to the Bare/Green grounding conductor from the cable to the switch.
- Connect the White grounded (neutral) conductor from the feeder, to one of the grounded (neutral) screw terminals on the receptacle.
- Connect the White grounded (neutral) conductor from the cable to the switch, to the other grounded (neutral) screw terminal on the receptacle.
- Connect the Black ungrounded (hot) conductor from the feeder to one of the ungrounded (hot) screw terminals on the receptacle.
- Connect the Black Ungrounded (hot) switched conductor from the cable to the switch, to the other ungrounded (hot) screw terminal on the receptacle.
- Using a twist-on wire connector rated for use with two 12 AWG conductors, splice the two Red ungrounded (hot) conductors together.
Install the breaker
- Terminate the Bare/Green grounding conductor to the grounding bus bar.
- Install the breaker in the panel (make sure it is in the OFF position).
- Terminate the White grounded (neutral) lead from the breaker to the neutral bus bar.
- Connect the White grounded (neutral) conductor from the circuit to the neutral terminal of the breaker.
- Connect the Black ungrounded (hot) conductor to one of the ungrounded (hot) terminals on the breaker.
- Connect the Red ungrounded (hot) conductor to the other ungrounded (hot) terminal on the breaker.
Turn on and test the GFCI breaker
- Switch the breaker to the ON position.
- Press the TEST button on the breaker.
- Switch the breaker back to the ON position.
If the breaker will not switch on, there is a ground-fault, the wiring is wrong, or the breaker is bad. Detect and correct the fault, and reset the breaker.
tl;dr
Here is an image showing what the finished circuit should look like.
Click for larger view
NOTES:
- If using metal boxes, make sure to bond them to the grounding system.
- You can also use 12/2 with ground, but you might find that if both devices are run simultaneously, the breaker might trip.
Related Topic
- Electrical – How to wire a gcfi outlet in this situation
- Electrical – Can a GFI shutdown a second non-GFI outlet
- Wiring – No neutral kitchen wiring
- Electrical – How to replace electrical outlets that have two wires under same screw
- Electrical – Help with re-wiring a two circuit outlet with one controlled by switch
- Electrical – piggyback off a hard-wired dishwasher circuit for a disposal
- Electrical – Wiring for GFCI with 3 cables
Best Answer
This is complicated
Think for a minute. Does your garbage disposal run continuously? No, why not? Because there is a switch on the wall you must throw. When the switch is off, does the dishwasher still work? Ok, then clearly the two sockets on the receptacle are controlled separately. That's easy to do by breaking off the tab separating the two screws.
There is no way to provide that with a GFCI receptacle. You would need to provide GFCI protection another way.
Ok, go down to the service panel. Is the dishwasher and disposal on the same exact breaker? Is it a single breaker? A double-width / 2-pole breaker? Two separate breakers, hopefully adjacent?
Reason I ask is it was common to put the disposal and dishwasher on a multi-wire branch circuit. It uses a 240V double breaker (or 2 adjacent breakers) plus neutral to provide two 120V circuits on only 3 wires. . It powers one 120V load between black and neutral, and the other 120V load between red and neutral. It is very common to punch this down to a 2-socket receptacle which has been split (and the disposal is also switched). ---- If you have this setup, you can easily fit GFCI protection by using a 2-pole GFCI breaker. It's an expensive breaker but it protects both circuits, and any other way of doing this is rather ugly. Remember the disposal must be switched, and you can't switch a GFCI receptacle.
If both dishwasher and disposal are on the same simple breaker, you can fit GFCI protection by fitting a plain 1-pole GFCI breaker. You can also protect it with an inline GFCI device such as a deadfront, which would need to be along the circuit's cable between the receptacle and service panel.