dishwasher and disposal

[George Stolz]

Re: dishwasher and disposal

Originally posted by dana1028:
430.6(A)(1) Table Values.
...

This code section on motors requires you use tables in Art. 430 to determine conductor and OCPD sizes....not mfr. nameplate information.

What about exception 3 to that section?

 

[jwelectric]

Re: dishwasher and disposal

430.6 (A)(1) Exception No. 3: For a listed motor-operated appliance that is marked with both motor horsepower and full-load current, the motor full-load current marked on the nameplate of the appliance shall be used instead of the horsepower rating on the appliance nameplate to determine the ampacity or rating of the disconnecting means, the branch-circuit conductors, the controller, the branch-circuit short-circuit and ground-fault protection, and any separate overload protection.

Originally posted by jw electric
422.10 (A) Individual Circuits. The rating of an individual branch circuit shall not be less than the marked rating of the appliance or the marked rating of an appliance having combined loads as provided in 422.62.
The rating of an individual branch circuit for motor-operated appliances not having a marked rating shall be in accordance with Part II of Article 430.

When the appliance has the rating marked on it then this is what rules the size of the circuit.

While teaching an inspectors class I am sure to point out that most electricians think that bigger is better. 200 amp main, #12 everywhere and hurry up and finish. This mode of thinking is what can get some of them a reinspection charge.

The ART of electrical work is a dying art. What ever happened to the code book?

Most inspectors take the time to look at the outside AC/heat pump but few take the time to look at the dishwasher or disposal. I make it a point to cover these in detail during an inspectors class and add at the end of class, ?now let?s go get them.?

 

[dana1028]

Re: dishwasher and disposal

Originally posted by jw electric
422.10 (A) Individual Circuits. The rating of an individual branch circuit shall not be less than the marked rating of the appliance or the marked rating of an appliance having combined loads as provided in 422.62.

JW - what about this section? ..."or the marked rating of an appliance having combined loads as provided in 422.62."

Dishwasher + garbage disposal = combined loads.

Section 422.62 deals with appliances having motor loads.

422.62. Where a motor-operated appliance nameplate includes a HP rating, the rating shall not be less than the HP rating on the motor nameplate....calculated per 430.110(C)(1).

430.110(C)(1) says to use the HP tables of 430.147, 148...

[ October 01, 2005, 03:37 PM: Message edited by: dana1028 ]

 

[jwelectric]

Re: dishwasher and disposal

Originally posted by dana1028:
JW - what about this section? ..."or the marked rating of an appliance having combined loads as provided in 422.62."
422.62. Where a motor-operated appliance nameplate includes a HP rating, the rating shall not be less than the HP rating on the motor nameplate....calculated per 430.110(C)(1).

There are a few articles that need to be look at closely when addressing a dishwasher. First being 430.6 due to the fact that the dishwasher has a motor. Here we are told to look at 422 this dishwasher being an appliance as shown here.

430.6 (A)(1) Exception No. 3: For a listed motor-operated appliance that is marked with both motor horsepower and full-load current, the motor full-load current marked on the nameplate of the appliance shall be used instead of the horsepower rating

In 422.10 (A) we are told that the branch circuit is not to be less that the appliance and any combination of loads in that appliance such as the motor and the heater for the water.

422.10 (A) Individual Circuits. The rating of an individual branch circuit shall not be less than the marked rating of the appliance or the marked rating of an appliance having combined loads as provided in 422.62.
The rating of an individual branch circuit for motor-operated appliances not having a marked rating shall be in accordance with Part II of Article 430.

422.10 tells us to look at 422.62 when there is a marked rating on the appliance and go to 430 when there is no marked rating. Most dishwashers have a label as well as a manual so let?s look at 422.62.

422.62 (B) Additional Nameplate Markings. Appliances, other than those factory-equipped with cords and attachment plugs and with nameplates in compliance with 422.60, shall be marked in accordance with 422.62(B)(1) or (B)(2).

(1) Marking. In addition to the marking required in 422.60, the marking on an appliance consisting of a motor with other load(s) or motors with or without other load(s) shall specify the minimum supply circuit conductor ampacity and the maximum rating of the circuit overcurrent protective device.

This requirement shall not apply to an appliance with a nameplate in compliance with 422.60 where both the minimum supply circuit conductor ampacity and maximum rating of the circuit overcurrent protective device are not more than 15 amperes.

I separated this section for clarity of the second part. (This requirement shall not apply to an appliance with a nameplate where both the supply conductor and the overcurrent protective device are not more than 15 amperes.)

The manufacture?s label on the dishwasher that I posted earlier stated that the dishwasher was to be supplied with a 15 amp circuit. Therefore should this dishwasher be supplied with a 20 amp OCPD and have no disposal it would be in violation of 422.62 and 110.3(B).


Edited to change 433.62 to 422.62. Thanks Eric


[ October 01, 2005, 08:29 PM: Message edited by: jwelectric ]

 

[dana1028]

Re: dishwasher and disposal

JW - I am not disputing your 422.62(B) example of a stand alone dishwasher....the marking, non-marking, the size of the circuit for a stand alone appliance.

This discussion started with 2 appliances with motors on the same circuit.

I still contend that when multiple loads are on an appliance with motor circuit you need to apply Art. 430 values. There is nothing in 422.62(B) that says otherwise.


If we ignore the multiple motor load issue and stipulate 430.6(A)(1), x-3 applies, then we can indeed install a 1/3 HP garbage disposal with a dishwasher. I concur with you.

However, since very few 1/3 HP garbage disposals are being installed in new homes (at least in the neighborhoods I see in Nor Cal) or as replacements (they are in the 1/2 to 1 HP range) we are back to the original point of my argument....you can't get both of these appliances on a 15A circuit.

So - I stipulate, you are correct. If we install the baby-size (1/4 to 1/3 HP) garbage disposals on the same circuit with the dishwasher we can sqeeze under the wire for a single 15A circuit.

For those of us who don't install the small units or know homeowners will want a larger unit this (15A single circuit) is not an option.

 

[jwelectric]

Re: dishwasher and disposal

We are on the same page as to the disposal. What I was pointing out is the data sheet for most dishwashers specifies that the dishwasher be on a 15 amp circuit.

And the fact that if the dishwasher calls for a 15 amp circuit and the electrical contractors chooses to install it on a 20 amp circuit that it is a violation.


I stand in agreement with you as far as the disposal. Again here we find numerous violations in the residential wiring.

Install a circuit for both and in most cases a 15 amp circuit is what is called for.

 

[iwire]

Re: dishwasher and disposal

Originally posted by jwelectric:
We are on the same page as to the disposal. What I was pointing out is the data sheet for most dishwashers specifies that the dishwasher be on a 15 amp circuit.

I am guessing here but I would bet it says a dedicated 15 amp circuit.

 

[Physis 2]

Re: dishwasher and disposal

It's good to see that things haven't changed too much.

Hi Bob.

 

[jwelectric]

Re: dishwasher and disposal

Good evening Sam.

 

[Physis 2]

Re: dishwasher and disposal

Good afternoon Mike.

 

[LarryFine]

Re: dishwasher and disposal

Good night, Gracie.