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Old 06-27-2011, 06:06 PM   #1
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Garbage disposal circuit


We are putting in 2 garbage disposals into 2 sinks relatively close to each other. Amp loads are 6.9 and 8.1 which equals 15, can I run them both off a single 20 amp circuit, or should I run dediated circuits, and if dedicated, I would assume 15 amp circuits would be ok. NEC is in effect; would one circuit satisfy code?
Thanks.

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Old 06-27-2011, 07:59 PM   #2
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We are putting in 2 garbage disposals into 2 sinks relatively close to each other. Amp loads are 6.9 and 8.1 which equals 15, can I run them both off a single 20 amp circuit, or should I run dediated circuits, and if dedicated, I would assume 15 amp circuits would be ok. NEC is in effect; would one circuit satisfy code?
Thanks.
What are the horsepowers?

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Old 06-27-2011, 08:13 PM   #3
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Garbage disposal circuit


3/4 hp & 1/2 hp. They are Isinkerators, ones a 5 the other a 5xp.
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Old 06-27-2011, 08:22 PM   #4
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3/4 hp & 1/2 hp. They are Isinkerators, ones a 5 the other a 5xp.
The 3/4HP will need a dedicated #14 circuit with a 35A breaker.

The 1/2HP will need a dedicated #14 cicuit with a 25A breaker.

They are motors and the requirements are specific. If you want I would be happy to provide the calculations for each motor.
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Old 06-27-2011, 08:52 PM   #5
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The 3/4HP will need a dedicated #14 circuit with a 35A breaker.

The 1/2HP will need a dedicated #14 cicuit with a 25A breaker.

They are motors and the requirements are specific. If you want I would be happy to provide the calculations for each motor.
That is TOTAL BS. You do not calculate residential appliance motor circuits using motor calculations.
Read NEC 430.6 in totality. Especially the exceptions.

Last edited by brric; 06-27-2011 at 08:57 PM.
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Old 06-27-2011, 09:16 PM   #6
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Originally Posted by Murdy View Post
We are putting in 2 garbage disposals into 2 sinks relatively close to each other. Amp loads are 6.9 and 8.1 which equals 15, can I run them both off a single 20 amp circuit, or should I run dediated circuits, and if dedicated, I would assume 15 amp circuits would be ok. NEC is in effect; would one circuit satisfy code?
Thanks.
If you want to avoid problems and comply with the appliance instructions, run individual 15 amp circuits to each GD.
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Old 06-27-2011, 09:31 PM   #7
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That is TOTAL BS. You do not calculate residential appliance motor circuits using motor calculations.
Read NEC 430.6 in totality. Especially the exceptions.

Thank you. I knew this was BS, but I was waiting for a real electrician to respond.

In my 30 years of industrial, commercial and multi-family construction, I have never seen a disposal protected with anything other than a 15 or 20 circuit breaker. The statement by our "Inspector" is ludicrous. Now you have residential wiring protected by a much bigger breaker than it safely should be.

This is the danger with so many of these sites, you get some "experts" who claim to be "State Electrical Inspectors" and some poor fool will listen to them

430.6 (A) (1) exception #3 - correct?

electures: You're a fool if as a inspector you can't tell someone how to safely wire a garbage disposal
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Old 06-27-2011, 09:42 PM   #8
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Garbage disposal circuit


Yeah, nobody sizes residential motor-based appliance circuits that way. Nor is there any good reason to. It wouldn't even be code compliant to use those breaker/conductor combinations if these disposals are cord-and-plug connected.

I'd install one 20A circuit for both of them. I'm not aware of any requirement that garbage disposals have a dedicated circuit. You can even add other receptacles on that circuit if you want to get more use out of it. However, you can't count it as one of the "small appliance circuits" required in a kitchen.

EDIT: brric makes a good point - the disposal instructions may call for a dedicated circuit to each.
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Old 06-27-2011, 10:14 PM   #9
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Garbage disposal circuit


Thanks for all the input,
"It wouldn't even be code compliant to use those breaker/conductor combinations if these disposals are cord-and-plug connected"
That did make me scratch my head, but what the heck do I know.
And when in doubt, read the instructions.
My panel is getting a little crowded, and I though maybe I could get away with one 20 instead of 2 15's.
I appreciate eveyone's input.
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Old 06-28-2011, 05:01 AM   #10
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Garbage disposal circuit


Do you know if your panel can accept twin/tandem breakers? Then it would only use one breaker slot.
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Old 06-28-2011, 05:18 AM   #11
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I think in Canada we can put one garbage disposal on the same circuit as a dishwasher, but im not sure about putting 2 disposal's on the same circuit.
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Old 06-28-2011, 06:20 AM   #12
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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.

They both could be run off a single 20 amp circuit.
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Old 06-28-2011, 07:13 AM   #13
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Thank you, NJMarine, for a definitive answer.
And, SD515, thanks for the input, my panel does accept the smaller breakers, and I will be using some. Still trying to conserve a circuit if I really don't need the extra one.
Thanks all.
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Old 06-28-2011, 06:26 PM   #14
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As a couple others have mentioned…run ‘em both off a 20A circuit, them only. Besides, when are you going to be using them at the same time? Even then, the duration probably wouldn’t be very long.
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Old 06-29-2011, 03:12 PM   #15
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Garbage disposal circuit


brric,

I think you teed off electures, he has not made another post since you called him on the OCPD requirements for the garbage disposers.

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