I have seen answers to similar questions but not sure they address my situation. I recently "installed" 2 separate 20A circuit runs for a dishwasher and a garbage disposal respectively (overkill perhaps). I will be installing a switch between the breaker and the garbage disposal receptacle next. I will then install the receptacle underneath the kitchen sink where the garbage disposal and dishwasher will plug in. I believe I have read that NEC 2014 requires GFCI for a dishwasher but not for disposal (seems backward to me but okay). If so, does this mean I should install a 2-gang box with one GFCI duplex receptacle for the dishwasher and then one standard (or another GFCI) duplex receptacle for the disposal? Can I use one GFCI duplex receptacle for 2 separate circuits?
Electrical – Do I need two separate duplex receptacles for dishwasher (GFCI) and garbage disposal
dishwasherelectricalgarbage-disposalgfcireceptacle
Related Solutions
If you don't plan on using any 20 ampere cord-and-plug devices, there is no reason to install 20 ampere rated receptacles. Circuits rated for 20 amperes are useful in the home, because they can support more devices. 20 ampere receptacles are often not advantageous, except possibly in a workshop or garage.
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
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- Electrical – Dishwasher and garbage disposal wiring in same gang box
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- Electrical – Wiring dishwasher and garbage disposal
Best Answer
Yes, you are right. Current code wants the dishwasher GFCI protected. However, unlike the dishwasher, there is no specific article that explicitly states a disposal requires one.
A Double pole GFCI 20 Amp breaker can protect two individual appliances. The Wiring is known as a MWBC "multi-wire branch circuit" and uses 12-3 "Black, Red, White, and Ground".
However, current code also wants everything in a kitchen, including dishwashers to be ARC-fault protected. One solution is to use a Double-Pole Dual GFCI/ARC fault 20 Amp breaker.
But since you ran two separate branch circuits I don't think code allows you to combine the neutrals as one in the panel because the conductors are not in the same sheath/raceway when they leave the panel. In which case, you would just do as you mentioned using a 2-gang box with one GFCI and one regular outlet, which is probably far way less expensive!