Disposal & Dishwasher tied toghether?

[Jeff Zehnder]

Found this in yesterday’s new condo inspection… the breaker for the dishwasher and disposal are connected together, they are the two 15 amp breakers on the upper right. Does this make sense? Is there a reason to do this?

[Gunnar Alquist]

Found this in yesterday’s new condo inspection… the breaker for the dishwasher and disposal are connected together, they are the two 15 amp breakers on the upper right. Does this make sense? Is there a reason to do this?

Jeff,

Code requires receptacle outlets that share the same yoke to turn-off simultaneously. I don't remember the exact wording or article section. Basically, if you remove the little tab from the side of a duplex receptacle outlet, you can attach separate circuits to each outlet. But, there is a danger of electrocuting someone who only shuts off one circuit. As a result, the NEC requires both circuits to turn off simultaneously. This is now true of multi-wire circuits, which that also appears to be.

[Jim Port]

Gunnar is correct on both points.

[Welmoed Sisson]

Funny this should pop up today. We just had our 15-year-old dishwasher replaced this morning, and the install guys found that it was on the same circuit as the disposal. He said that code now requires the two to be on different breakers. He got the new machine installed (had to put in a junction box), but I know that when/if we do any upgrades or renovations to the kitchen we will have to get a new branch circuit for the disposal. When did this become code, I wonder?

[Vern Heiler]

Funny this should pop up today. We just had our 15-year-old dishwasher replaced this morning, and the install guys found that it was on the same circuit as the disposal. He said that code now requires the two to be on different breakers. He got the new machine installed (had to put in a junction box), but I know that when/if we do any upgrades or renovations to the kitchen we will have to get a new branch circuit for the disposal. When did this become code, I wonder?

If you have a multi-wire circuit, as depicted by the OP, then the disposal and dishwasher are on different breakers.

[Roland Miller]

Funny this should pop up today. We just had our 15-year-old dishwasher replaced this morning, and the install guys found that it was on the same circuit as the disposal. He said that code now requires the two to be on different breakers. He got the new machine installed (had to put in a junction box), but I know that when/if we do any upgrades or renovations to the kitchen we will have to get a new branch circuit for the disposal. When did this become code, I wonder?


It would only be required by "code" if it was required in the manufacturer's installation instructions. My DW instructions state it has to be on a 15 amp breaker or fuse unless it is with a kitchen waste disposal then it is required to be on a 20 amp breaker or fuse.

[Corey Friedman]

Funny this should pop up today. We just had our 15-year-old dishwasher replaced this morning, and the install guys found that it was on the same circuit as the disposal. He said that code now requires the two to be on different breakers. He got the new machine installed (had to put in a junction box), but I know that when/if we do any upgrades or renovations to the kitchen we will have to get a new branch circuit for the disposal. When did this become code, I wonder?

Hello Welmoed,

The code does not say they have to be on separate circuits (different breakers).

Corey

[Roland Miller]

Hello Welmoed,

The code does not say they have to be on separate circuits (different breakers).

Corey

The code may require it depending on the listing and manufacturers instructions. Not everything is written in the code book concerning the installation.

[Bill Kriegh]

The NEC (code) MAY require the two appliances be on separate circuits depending on either the manufacturer's requirements (which code dictates that you have to follow) OR if the ratings of the appliance exceed certain values based on circuit capacity. And, some of this depends on whether the appliance is cord and plug connected or hard wired. The requirements may change over time as older appliances are replaced with more efficient ones (use less power) or appliances that use more power for "features" the old ones didn't have.

My rule of thumb is to install two simplex receptacles on individual 20 AMP circuits to cover manufacturer requirements (if any) and the ability to have right angle cord ends on both appliances - which happens every so often.

In the overall scheme of things though, a disposer is seldom on more than a minute or two and not likely to cause problems if it's on a dishwasher circuit - doesn't make it "legal" necessarily though and I wouldn't mind seeing an exception for putting both on the same circuit in a residence, subject to something like a horsepower limit on the disposer and wattage limit on the dishwasher.

[Corey Friedman]

The code may require it depending on the listing and manufacturers instructions. Not everything is written in the code book concerning the installation.

Roland,

Instructions with a particular specification are a given. I was commenting on the post that indicated an installer said that it is a code requirement and that is simply not the case.

Corey

[Roland Miller]

Roland,

Instructions with a particular specification are a given. I was commenting on the post that indicated an installer said that it is a code requirement and that is simply not the case.

Corey

I often cited a violation of NEC 110.3(B)--"Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling."
I understand what you are saying. I am saying there would be a code violation if the instructions were not followed.

Thanks for your input--it is always valuable.

[Don Hester]

As stated above that is a multi-wire branch circuit and and as such need to be tied together (turn-off simultaneously) because they share the neutral. I see a lot of multi-wire circuits. This is one of the scenarios I have no real issue with but I really hate it when used on most branch circuits.

As for the dishwasher the manufacturer would spell out if need to be a 20 amp or not. Some are fine on a 15 amp breaker.

Hard to tell from a pic but it does look like 12 ga wire so you could put in a 20 amp breaker.