Wall switch for Dishwasher

Shandon

I'm in the middle of redoing our kitchen. Running new electric for counters, Fridge/Gas range, DW, Disposal, etc. I was at my in-laws for dinner last night and my mother in-law showed me that she has a wall switch for the dishwasher. Is this required? I am planning on using plugs under the sink cabinet for the DW and the disposal. If the switch is for disconnect purposes, wouldn't the plug pass as that?

pcampbell

You don't need a wall switch but you do need some way to turn it on/off. You could get the In Sinkerator counter switch, or just do a switch under the counter.

EDIT: Sorry I misread and was thinking disposal. Why don't you A) Check to see if your DW cant be wired to a plug, B) wire the Dishwasher up to a plug and call it a day. What JV said

J. V.

If the dishwasher has a cord and plug no diconnect is required. If it is hard wired it needs a disconnect.

Shandon

Thanks. I am going to wire the DW & Disposal with plugs and a split outlet. I did get the cool In Sinkerator push button for the disposal. Our sink only has one hole but I'm going to put the button on the tile backsplash just above the basin.

Thanks again.

J. V.

Shandon,
You are aware that this split outlet is a multi wire circuit right? You need a breaker for each circuit and they must be tied together. Or you can use a double pole 20 amp breaker if you like. This means that when you turn off the breaker, both legs of the circuit are opened and disconnected. You will share the neutral with both circuits.

Shandon

I did run them as seperate circuits, and I was running to two breakers, but what do you mean by "Tied Together"? I like the double pole idea, bt I'm already using tandem breakers because of the limited space. Can I Tie the tandems?

220/221

Not here. We run one 20 amp circuit to the switcch for the DW/disp then a 3 wire to the 1/2 switched outlet. Pigtails on the appliances for disco.

Speedy Petey

With two circuits you do need a handle tie in this case.

I see no reason for two circuits though. I do as 220/221 and run one 20A circuit for both the DW and disp.

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Shandon

Okay, now I'm more confused. I thought I read that it was required to have a dedicated circuit for the DW and it was recommended to have a dedicated line for the Disposal as well.

Speedy Petey

It's no code requirement. Unless it is a local amendment.

Where do you think you read this?

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Piedmont

I love kitchen code questions, that question my friend is just one of those things, there's basically 2 rules of thought. The no you can't follow that

NEC 2002

210.21(B)(2) and 210.23(A)(1) - (2)

Recepts under sink can not have a connected load over 12A for a 15A rated circuit. Dishwashers are between 10-12A, garbage disposals 7-8A, connecting the two and you break the "connected load" code. It also would imply a potential to break the 80% load rule.

NEC requires there to be NO accessible recepts under the kitchen countertop unless it is for a dedicated appliance. The NEC also prohibits tying into any dedicated appliance circuits. Since the garbage disposal must plug into a dedicated appliance circuit, and you're not allowed to tie into them, that means you can't tie the dishwasher and disposal into the same circuit.

The "yes it's allowed" school argue that the 80% rule only applies to certain types of circuits of which the DW + Disposal on the same circuit does not apply. Meaning, you can put both on the same circuit and they both may indeed use 100% of the circuit while on and doesn't break code.

I've not come across how this school overcomes the part the NEC requires any recepts under kitchen countertops to be for a dedicated appliance. How can one tie the DW + Disposal together and call it a dedicated appliance (unless that rule isn't actually code, or uses or implies the plural form "dedicated appliances"). I saw someone say to use a switch where, in one position only the DW can be used and in the other position only the disposal can be used in that way they say they maintain a dedicated circuit status using a single breaker... but only one item can be used at a time.

Not to say I'm right or wrong or have my facts right I hope others can enlighten.

pcampbell

<thread hijack>Could you tell me about the 80% rule. I always read this applies to appliances which run for 3+ hours, which neither DW or disposal do.

I added up the ampere rating on DW and disposal and it came out to under 20, but 99% sure it was NOT under 16 (80% of 20). I want to say it was 9.2 for DW, and 6.9 or something for 3/4 HP disposal.

In retrospect I would have run a 12/3, but I didn't...

Shandon, I think what they are saying, is if you are running a split outlet, that you need a "common trip" tandem. So if one trips, the other trips. You did not mention if you ran a 12/3 wire, or two separate 12/2s or 14/2s. The experts will chime in regarding when a common trip tandem is required, but to be safe, it seems like if you have 2 circuits within the same outlet box, that is probably reason enough.

Speedy Petey

I'd like you to do me a favor and show me where in the NEC it says this.


Sorry, none of the code sections you quoted holds any water.

210.21(B)(2) says that each receptacle can only be loaded to 16A (on a 20A circuit). A duplex receptacle is TWO receptacles.

210.23(A)(1) does NOT apply

210.23(A)(2) says 50% ONLY if: "lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied."

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BigJimmy

Neither DW or disposal are considered continuous loads.

Please be careful about the wording here. One of my peeves is the way people seem to use tandem and double pole breaker interchangeably; they are not. A tandem is a two-breaker device that occupies one full position in a panel and both load side terminals are connected to the same bus/lug. Therein, "common trip" is meaningless as applied to a tandem and would be stupid since the circuits would be separate. That is, if one circuit tripped, it would be nothing but a nuissance to trip the other. On the other hand, a double-pole breaker occupies two adjacent single spaces and provides connections to both busses of the split phase system (L1, L2) yielding 240V AC across its terminals (a volt meter reading across the load terminals of a tandem would be zero). These breakers have a tie between handles so that a trip always results in disconnection of both ungrounded conductors.

Now I'm no Speedy (although I aspire to be in this action/comedy/drama that I'm starring in), but I believe that in many instances, electricians will run a 3/c MWBC to the JB under a sink in anticipation of powering both disposal and DW. According to the 210.4(B) of the 2005 NEC,


(B) Devices or Equipment.

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Shandon

WOW! Thanks for all of the great responses. I didn't expect this much.

Anyway, I think I'm going to look for a "common trip" tandem breaker. And if I can't find that, I will just put in another box and have two single plug outlets in each.

Thanks again.

Now if I could just get this much response from my tile backsplash question.