dishwasher and disposal

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single_phase

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I'm In NC visiting with my mom. She just moved her brand new home. My question is can you put a dishwasher and garbage disposal on a 15 amp circuit? I have never seen this done. And I was told it passed electrical insp. This doesn't sound right to me. And there is no means for disconnect hard wired. If this is wrong may I please have the code article for the last code.

Thanks
 
charlie b

charlie b

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Staff member
Location
Lockport, IL
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Retired Electrical Engineer
Re: dishwasher and disposal

The NEC does not prohibit placing the DW and the disposal on the same circuit; nor does it prohibit that circuit from being rated at 15 amps. I wouldn't do it; I'd use a 20 amp circuit, and I'd consider placing the two loads on separate circuits. But that is my own design choice, not a code requirement.

As to the absence of a disconnecting means: you might be able to take credit for the circuit breaker. But I think it would have to be in sight and lockable. Can anyone confirm or refute that statement?
 
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allenwayne

Senior Member
Re: dishwasher and disposal

Also look at 422.16 B 1 & 2 ,We have been cord connecting d/w , disp for quite awhile now ,
That 4 ft cord still makes it hard to get to.The 3 ft on the disposal is needed keeps it from being all over
 
jwelectric

jwelectric

Senior Member
Location
North Carolina
Re: dishwasher and disposal

I will pull a 14/3 to a switch box and feed the dishwasher with one and the disposal with the other. Depending where I am working, sometimes I will switch the dishwasher but always the switch for the disposal.

Never both on one circuit.
 
peter d

peter d

Senior Member
Location
New England
Re: dishwasher and disposal

I don't see a problem with putting both on the same 15 amp circuit. These loads will rarely be coincidental. Usually you scrape the junk off the plates into the disposer first then put the dishes in the dishwasher and run it after. :D
 
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peter

Senior Member
Location
San Diego
Re: dishwasher and disposal

I'm glad you agree with me. ;)
You could put a three way switch in the connection to the DW and Disposal. That way, only obe appliance will have power at a given time.
~Peter
 
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Physis 2

Guest
Re: dishwasher and disposal

I think I like that Peter, :D

Will it work for 210.23 if the two would otherwise be over?

I'll leave my position unposted. ;)
 
electricmanscott

electricmanscott

Senior Member
Location
Boston, MA
Re: dishwasher and disposal

Originally posted by peter:
I'm glad you agree with me. ;)
You could put a three way switch in the connection to the DW and Disposal. That way, only obe appliance will have power at a given time.
~Peter
Click to expand...
Ok now I don't agree with Peter.
 
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dana1028

Senior Member
Location
San Francisco Bay area
Re: dishwasher and disposal

In his post, single-phase indicated these appliances were hard wired. If that is correct, then 210.23(A)(2) does not apply to this situation.

According to Creighton Schwann however, 430.53(A) does apply....for this installation to fly, the garbage disposal (or dishwasher) cannot be rated more than 1/4 HP...and most folks are certainly putting larger disposals than that in their homes.
 
George Stolz

George Stolz

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Location
Windsor, CO NEC: 2017
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Re: dishwasher and disposal

Originally posted by dana1028:
In his post, single-phase indicated these appliances were hard wired. If that is correct, then 210.23(A)(2) does not apply to this situation.
Click to expand...
Actually, the fact that the "fastened-in-place" appliances are hard wired has no bearing on this. There is no mention of how the "fastened-in-place" equipment is connected to their supply. Only the "other stuff" bears those stipulations. :)
NEC-2002 210.23(A)(2) Utilization Equipment Fastened in Place. The total rating of utilization equipment fastened in place, other than luminaires (lighting fixtures), shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied.
Click to expand...
Since there are no other loads (ie receptacles for 210.52, or lighting outlets), 210.23(A)(2) doesn't apply at all! :)

At any rate, the disposals I see are rated for 6 amps. The dishwasher in my kitchen has a rating of 5.8 amps motor load. So unless my under-knowledge of Article 430 betrays me, these two motor loads could occupy the same circuit.

I am in for some serious headaches if we fully explore the bounds of this thread - I have a lot to learn about 430! :D

[ September 30, 2005, 07:34 AM: Message edited by: georgestolz ]
 
jwelectric

jwelectric

Senior Member
Location
North Carolina
Re: dishwasher and disposal

George how much does the heater in the dish washer pull?

A close look at 422.62 helps the inspector when making inspections in a dwelling unit. Read carefully 422.62 (B)(1).
?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.?
Click to expand...
How many dishwashers have you seen that are marked at over 15 amp circuit? Check out this spec sheet for a $800 dishwasher.

The size of the circuit will be found close to the bottom of page two.

:)

[ September 30, 2005, 08:48 AM: Message edited by: jwelectric ]
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Re: dishwasher and disposal

In case anyone is wondering...

"*With Food Disposer in the same circuit, a 20 AMP circuit breaker is required."

Wiring in accordance withm manufacturer's instructions is an NEC requirement, after all.
 
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dana1028

Senior Member
Location
San Francisco Bay area
Re: dishwasher and disposal

Originally posted by georgestolz:
Originally posted by dana1028:
[qb]

QUOTE]Well, that doesn't appear to be a totally accurate statement either.
...
At any rate, the disposals I see are rated for 6 amps. The dishwasher in my kitchen has a rating of 5.8 amps motor load. So unless my under-knowledge of Article 430 betrays me, these two motor loads could occupy the same circuit.

:D
Click to expand...
George:

430.6(A)(1) Table Values. The table values given in Tables 430.147,148,149, 150 includeing notes, shall be used to determine the ampacity of conductors or ampere ratings.....instead of the actual current rating marked on the motor nameplate.


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

jwelectric

Senior Member
Location
North Carolina
Re: dishwasher and disposal

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.
:)
 
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