Dishwasher and Disposal wiring.

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Stu Goforth

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Hi Everyone. Say I am having a problem with the inspectors. I wired a Dishwasher and a Disposal on the same 20A ckt. The inspector says that I need seperate ckts to each of these. The dishwasher has a FLA of 9.6A with 2.7 of that being the motor The disposal has a FLA of 6.7 all of which is the motor. According to my calculation the total Current of these two is 17.975 A Any one tell me why I can't put these on the same Ckt. The Inspector sites article 210.23 (a) (2). However there are no other loads on this ckt.

Stu Goforth
Contractor
Cheyenne, Wy
 
Stu, welcome to the forum.

Chances are pretty good that the dishwasher's instructions call for a dedicated 15A or greater circuit, many of them do.

As for the citation, ask the inspector to walk out the front door with the portable disposal, or the portable dishwasher, take your pick. :roll:

I believe it's difficult to call them anything besides utilization equipment fastened in place.

That said, if you win in a confrontation on this issue with a Cheyenne inspector, I will personally drive up there and give you a case of beer. I have not heard of anyone succeeding on this topic, and those guys have a reputation for not backing down regardless of how silly their perceived "violation" is.

As a design practice, I always pull a multiwire circuit to the disposal/dishwasher. I'd recommend you do the same. Much better bang for the customer's buck. :)
 
One of my inspectors was adament that the dishwasher and disposal required seperate circuits per the NEC. He actually took the code book home over the weekend just to prove me wrong. Monday he says "you know what I found?" "Nothing?" I said "Nothing. Why does everyone do it then?"

Just because everyone does it doesn't mean it's code. When I was in the trade we always put them on seperate circuits too. It was a long time before I realized that the load didn't justify it.

I am the inspector therefore it shalt be done! Man I hate that attitude.
 
On one of my jobs a new inspector asked to see the instructions for the dishwasher and showed me where it said "The electrical supply must be a 110?120 volts, 15 or 20 amp properly grounded circuit. No other appliance or outlets should be on this circuit."

He said I needed to do a better job with the manufactures instructions per NEC 110.3. He said that he was going make a note he informed me and next time it would not be acceptable. He said if it happen again he would write it up and we would have to change it.

I said thank you for pointing it out to me and would do it the way he wanted it next time. He was quick to inform me that it had nothing to do with what he wanted but what the code required.
 
Hey I say Thank you to 81611 and Cowboy! I took your responces to our Chief Building Official and he finally agreed that this was not really a code violation. However he stated that seperate ckts is what his department wanted. I explained that when a customer "wants" something extra they usually pay for it, and if he was willing to pay for seperate ckts I would be happy to go install them. He declined my approach and let the installation stand as I did it. Again Thanks.

Stu
 
There also is nothing to stop you from putting them on individual 15 amp ckts either but there are those that will argue the point. I used to require 20 amps cause that's how I did it for 30 years untill I was asked to "show me"
 
Stu Goforth said:
Hey I say Thank you to 81611 and Cowboy! I took your responces to our Chief Building Official and he finally agreed that this was not really a code violation.
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What, you didn't feel like showing him my response? I'm not working in Cheyenne again anytime soon, I'm not afraid. :lol:

Glad it worked out for you. Unfortunately, the Chief Building Official is not an inspector, so I guess I'm off the hook for the beer. However, I do feel compelled to drive up there and give you the beer because you stood your ground, and with some of those guys it can be a challenge. At the very least, you get a "good job." :D

I need to return to my usual custom of wagering 50?.
 
dont forget that we cannot load a circuit to more than 80 percent of the OCD rating
80 percent of a 20 amp breaker is 16 amps

you could not put them both on the same circuit after all..



just because its a 20 amp breaker doesnt mean you can draw 19.7 amps or whatever on it... it will trip within about 20 mins at that kind of load
 
izak said:
dont forget that we cannot load a circuit to more than 80 percent of the OCD rating
80 percent of a 20 amp breaker is 16 amps

you could not put them both on the same circuit after all.. ...
Click to expand...

What is the code reference?

just because its a 20 amp breaker doesnt mean you can draw 19.7 amps or whatever on it... it will trip within about 20 mins at that kind of load
Click to expand...

I only run my Disposer for seconds at a time and very seldom with the Dishwasher operating.
 
Stu Goforth said:
Hey I say Thank you to 81611 and Cowboy! I took your responces to our Chief Building Official and he finally agreed that this was not really a code violation. However he stated that seperate ckts is what his department wanted. I explained that when a customer "wants" something extra they usually pay for it, and if he was willing to pay for seperate ckts I would be happy to go install them. He declined my approach and let the installation stand as I did it. Again Thanks.

Stu
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You did win but it might prove costly in the future inspections.While your install is legal it is not a great design.The first time you install one that says dedicated circuit it will be costly.Often the DW is not selected till trim time,bit late to add a circuit.But you do deserve a beer for standing up to the inspector when he was wrong :)
 
1793 said:
izak said:
dont forget that we cannot load a circuit to more than 80 percent of the OCD rating
80 percent of a 20 amp breaker is 16 amps

you could not put them both on the same circuit after all.. ...
Click to expand...

What is the code reference?
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I agree with Norb: can you cite a reference for this?

1793 said:
just because its a 20 amp breaker doesnt mean you can draw 19.7 amps or whatever on it... it will trip within about 20 mins at that kind of load
Click to expand...

I only run my Disposer for seconds at a time and very seldom with the Dishwasher operating.
Click to expand...
While your sentiment is understood, I would like to mention that both loads must be considered present on the circuit. They are both non-continuous, but connected to the same circuit.

What I'm getting at is, having the two total up to 21 amps on the same circuit would be a violation of 210.19(A)(1), despite the fact that the breaker would likely never kick under normal use.
 
I typically use either a shared 20a circuit (most often), or two 15a circuits, one for each. I have never had even a casual mention of either practice by an inspector, and I've been wiring for 35 years. (Yikes! :shock: )

No, I'm not saying that it's okay because we've done it that way, just that we've done it that way, and fo far, it's been okay. Okay?
 
izak said:
dont forget that we cannot load a circuit to more than 80 percent of the OCD rating
80 percent of a 20 amp breaker is 16 amps

you could not put them both on the same circuit after all.


just because its a 20 amp breaker doesnt mean you can draw 19.7 amps or whatever on it... it will trip within about 20 mins at that kind of load
Click to expand...

Izak, we can load any breaker to 100%, the 80% value is for continuous loads.

And yes, we can serve both from the same circuit.

Now, if a DW or Disp will meet the criteria of a continuous load, (180 min ) you have an argument.

Roger
 
argghh i cannot cite a code reference
which means i am probably wrong

i have been taught that we cannot load a breaker to more than 80 percent
and in my experience, if you load a 20 amp breaker to 18 or 19 amps, it will get Hot, and trip eventually.

again, i cannot cite a code ref. i am still looking

apologize for opening my mouth without some article numbers available to back me up
 
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