Home>Discussions>ELECTRICAL & LIGHTING>Wiring an outlet for a dishwasher and garbage disposal
48 posts / 0 new
Last post
HandyWannabe
Wiring an outlet for a dishwasher and garbage disposal

Hello All,
I am trying to wire a 12/2 romax to a wall outlet under the sink to service the dishwasher and garbage disposal all on one outlet, but top outlet of the two I would like to have controlled by a switch above the counter. The bottom part on the other hand, I would like to have hot at all times for the dishwasher. Both off course protected by a circuit breaker in the basement below.
Is there a way to break the connection between the top and bottom outlets within the unit?
If not, what is the common practice to accomplish this, so that the dishwasher and garbage disposal live on the same outlet?

Thanks.

kentvw
Re: Wiring an outlet for a dishwasher and garbage disposal

Easy.

If you look at the side of the duplex receptacle you will notice that there are two side screws on each side and that between them is a little tab of metal that connects the two sides of the receptacle. You can break that tab off with a needle nose pliers.

One side of the receptacle has silver screws and the other side are brass colored. ONLY break the tab on the brass screw side. It is the hot or black side. The other, silver side is the white or neutral side.

Tie the black coming from the panel to the white going to the switch and leave a pigtail from that connection to go to the top brass screw.

Tie the black coming from the switch to the bottom brass screw.

Tie the white coming from the panel to one of the silver screws on the receptacle.

Tie both grounds together and leave a pigtail to connect to the receptacle.

Done, top is switched bottom is not.

heinselectric
Re: Wiring an outlet for a dishwasher and garbage disposal

FYI,
Many towns now require separate circuits for the garbage disposal and dishwasher. I believe it is in the NEC (I'm just too lazy to look it up right now). When I used to do new construction houses, they didn't require separate circuits and we NEVER had a problem with circuit overload, even when wired with the kitchen outlet circuit. You should be fine in that respect, however, I always suggest following local electrical codes.

Re: Wiring an outlet for a dishwasher and garbage disposal

Fixed appliances require separate circuits. typically 20 amp circuits

kentvw
Re: Wiring an outlet for a dishwasher and garbage disposal
kentvw wrote:

Easy.

Done, top is switched bottom is not.

OOPPSS!

Actually there is a major bit of misinformation in my post.

It should read:

“Bottom is switched top is not.”

:o

HandyWannabe
Re: Wiring an outlet for a dishwasher and garbage disposal

Great insights, thank you much. I hope one day to give valuable advice like you all.
Anyone need computer advice? :) Thanks again.

Born2Wire
Re: Wiring an outlet for a dishwasher and garbage disposal

If the appliances are already wired in place on the same circuit , and aren't gonna be swapped out anytime soon , and the switch is the only thing being added...... Then I would just follow the instructions given up-above. As long as the two appliances are already on the same circuit and there is no change in load (amps) this install is deemed existing and the switch can be installed with-out adding an aditional circuit. Keep in mind that the future may bring a neccesity to adding another circuit if one of the appliances gets replaced , bigger appliances possibly more (amps). I'm curious as to the amp reading when both these appliances are running at the same time. Just for laughs.;)

lmills148
Re: Wiring an outlet for a dishwasher and garbage disposal
Ravens53 wrote:

Fixed appliances require separate circuits. typically 20 amp circuits

Could you quote your source?

Re: Wiring an outlet for a dishwasher and garbage disposal
lmills148 wrote:

Could you quote your source?

First of all I want to welcome you to This old house discussions as a new member.

My answer should have been more in detail and I should have not made that general of a statement. Thanks for pointing this out to me. I was answering based on what the home owner asked. Can a dishwasher and a disposal be on the same circuit. I still say no.
most all residential dishwashers are a minimuim of 1200 watts at 120 volts that would be 10amps according to 210.23(2) it is 50% of the load and needs seperate circuit. Most residential disposals are 1/2 hp or more according to table 430.248 the motor is to draw a current of 9.8 amps. together at full load they combined for 19.8 amps. That exceeds 80% of the branch circuit. That is why I say it is not allowed.

lmills148
Re: Wiring an outlet for a dishwasher and garbage disposal
Ravens53 wrote:

First of all I want to welcome you to This old house discussions as a new member.

My answer should have been more in detail and I should have not made that general of a statement. Thanks for pointing this out to me. I was answering based on what the home owner asked. Can a dishwasher and a disposal be on the same circuit. I still say no.
most all residential dishwashers are a minimuim of 1200 watts at 120 volts that would be 10amps according to 210.23(2) it is 50% of the load and needs seperate circuit. Most residential disposals are 1/2 hp or more according to table 430.248 the motor is to draw a current of 9.8 amps. together at full load they combined for 19.8 amps. That exceeds 80% of the branch circuit. That is why I say it is not allowed.

I agree with that. You could also use a multi-wire branch ckt on one device.
I only ask to understand your point of view, and I appreciate your explanation.

lmills148
Re: Wiring an outlet for a dishwasher and garbage disposal
YukYuk wrote:

Harry - Ravens53,

There is no such citation 210.23(2). Perhaps you meant sections 210.23, 210.23(A), 210.23(A)(1) and 210.23(A)(2)??

However those sections don't say what you claim they say, nothing in 210.23 does for 2002, 2005 or 2008, I suggest you re-read them. As long as the dishwasher is fixed in place (not portable), as the garbage disposal would be, no such exclusions. Your own example provides equal to not exceeding 50%, which is likewise not restricted. As long as the circuit isn't providing power to non-fixed in place cord-and-plug

it is a non fixed cord and plug application

Quote:

equipment nor luminaires, only fixed in place devices corded or hardwired, no such 80% exclusion exists in those sections either for fixed-in-place appliances. Both of devices/equipment described in Harry's example: the DW (fixed in place) and the Disposer (either hardwired or cord-and-plug) are not prohibited from sharing the same 20 Amp circuit, as long as there are no luminaires or non-fixed-in-place devices sharing it according to the citation Harry apparently was referring to. Also, if the example disposer (9.8 A equal to or less than 50%) was the only fixed in place, and the dishwasher was portable (not fixed in place) and corded, as long as the DW didn't exceed 80% of the entire circuit rating, it too would not be prohibited according to these sections, although it would not be permissable to operate both at the same time if the combined load equalled greater than 100% of the branch circuit's rating.

Key to this discussion applicable to the original poster, is that the receptacle's face must be rated for 20 amps and that the switch the OP utilizes be of a sufficient rating for the disposer.

Its not unreasonable to assume that a d/w and g/d may be used at the same time.

I think raven was reffering to 210.23 (a)2 utilization equipment fastened in place... it goes on to say.. Totalrating..shall not exceed 50%..

this would be considered cord and plug fastened equipment since we were talking about wiring a device ...

I think everyone is aproaching the same conclusion from a different perspective. there is no need to split hairs over why we agree.

Pages

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.