Garbage Disposal Circuit - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 06-27-2011, 07:06 PM   #1
Member
 
Murdy's Avatar
 
Join Date: Mar 2011
Location: Illinois
Posts: 36
Rewards Points: 25
Default

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.

Advertisement

Murdy is offline   Reply With Quote
Old 06-27-2011, 08:59 PM   #2
Lic Electrical Inspector
 
electures's Avatar
 
Join Date: Dec 2009
Location: The Great Police State of New Jersey
Posts: 1,759
Rewards Points: 1,102
Default

Garbage disposal circuit


Quote:
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.
What are the horsepowers?

Advertisement

__________________
All responses based on the 2011 NEC.
If you live in New Jersey click here. All other states click here.
Please check with local, county and state officials as laws may vary.
Sizing motors here. Online motor calculator here. Online calculators here.
electures is offline   Reply With Quote
Old 06-27-2011, 09:13 PM   #3
Member
 
Murdy's Avatar
 
Join Date: Mar 2011
Location: Illinois
Posts: 36
Rewards Points: 25
Default

Garbage disposal circuit


3/4 hp & 1/2 hp. They are Isinkerators, ones a 5 the other a 5xp.
Murdy is offline   Reply With Quote
Old 06-27-2011, 09:22 PM   #4
Lic Electrical Inspector
 
electures's Avatar
 
Join Date: Dec 2009
Location: The Great Police State of New Jersey
Posts: 1,759
Rewards Points: 1,102
Default

Garbage disposal circuit


Quote:
Originally Posted by Murdy View Post
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.
__________________
All responses based on the 2011 NEC.
If you live in New Jersey click here. All other states click here.
Please check with local, county and state officials as laws may vary.
Sizing motors here. Online motor calculator here. Online calculators here.
electures is offline   Reply With Quote
Old 06-27-2011, 09:52 PM   #5
Master Electrician
 
Join Date: Mar 2010
Location: Indiana
Posts: 2,977
Rewards Points: 2,210
Default

Garbage disposal circuit


Quote:
Originally Posted by electures View Post
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 09:57 PM.
brric is online now   Reply With Quote
The Following 5 Users Say Thank You to brric For This Useful Post:
Anti-wingnut (06-27-2011), HouseHelper (06-28-2011), McSteve (06-29-2011), mpoulton (06-27-2011), tweak (07-16-2011)
Old 06-27-2011, 10:16 PM   #6
Master Electrician
 
Join Date: Mar 2010
Location: Indiana
Posts: 2,977
Rewards Points: 2,210
Default

Garbage disposal circuit


Quote:
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.
brric is online now   Reply With Quote
The Following 2 Users Say Thank You to brric For This Useful Post:
Anti-wingnut (06-27-2011), SD515 (06-27-2011)
Old 06-27-2011, 10:31 PM   #7
Member
 
Join Date: Oct 2009
Posts: 853
Rewards Points: 626
Default

Garbage disposal circuit


Quote:
Originally Posted by brric View Post
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
Anti-wingnut is offline   Reply With Quote
The Following User Says Thank You to Anti-wingnut For This Useful Post:
gregzoll (07-09-2011)
Old 06-27-2011, 10:42 PM   #8
Semi-Pro Electro-Geek
 
Join Date: Jul 2009
Location: Arizona, USA
Posts: 2,572
Rewards Points: 2,040
Default

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.
mpoulton is online now   Reply With Quote
The Following User Says Thank You to mpoulton For This Useful Post:
gregzoll (07-09-2011)
Old 06-27-2011, 11:14 PM   #9
Member
 
Murdy's Avatar
 
Join Date: Mar 2011
Location: Illinois
Posts: 36
Rewards Points: 25
Default

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.
Murdy is offline   Reply With Quote
Old 06-28-2011, 06:01 AM   #10
Electrician
 
SD515's Avatar
 
Join Date: Aug 2008
Location: Near Jackson Michigan Area
Posts: 1,451
Rewards Points: 502
Default

Garbage disposal circuit


Do you know if your panel can accept twin/tandem breakers? Then it would only use one breaker slot.
__________________
Kyle

Just because you can, doesn't always mean you should
SD515 is offline   Reply With Quote
Old 06-28-2011, 06:18 AM   #11
Newbie
 
Join Date: Jun 2011
Posts: 18
Rewards Points: 10
Default

Garbage disposal circuit


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.
Haligonian is offline   Reply With Quote
Old 06-28-2011, 07:20 AM   #12
Lic Elect/Inspector/CPO
 
Join Date: Apr 2011
Location: NJ
Posts: 369
Rewards Points: 250
Default

Garbage disposal circuit


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.
NJMarine is offline   Reply With Quote
The Following User Says Thank You to NJMarine For This Useful Post:
frenchelectrican (06-29-2011)
Old 06-28-2011, 08:13 AM   #13
Member
 
Murdy's Avatar
 
Join Date: Mar 2011
Location: Illinois
Posts: 36
Rewards Points: 25
Default

Garbage disposal circuit


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.
Murdy is offline   Reply With Quote
Old 06-28-2011, 07:26 PM   #14
Electrician
 
SD515's Avatar
 
Join Date: Aug 2008
Location: Near Jackson Michigan Area
Posts: 1,451
Rewards Points: 502
Default

Garbage disposal circuit


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.
__________________
Kyle

Just because you can, doesn't always mean you should
SD515 is offline   Reply With Quote
Old 06-29-2011, 04:12 PM   #15
A "Handy Husband"
 
rjniles's Avatar
 
Join Date: Feb 2007
Location: South Carolina Low Country
Posts: 4,233
Rewards Points: 2,376
Default

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.

Advertisement

__________________
Location:
Coastal South Carolina
rjniles is offline   Reply With Quote
The Following User Says Thank You to rjniles For This Useful Post:
gregzoll (07-09-2011)
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New Garbage disposal draining slowly. yoeye82 Plumbing 1 12-10-2010 04:40 PM
Wiring Size Calculations for New Service CorinthWest Electrical 7 12-07-2010 12:36 PM
Old garbage disposal question please help. linuxguy0481 Kitchen & Bath Remodeling 3 07-26-2009 11:03 PM
Garbage Disposal howard.wheaton Electrical 7 05-10-2009 07:36 AM
Garbage disposal muddog Electrical 3 06-07-2008 05:10 PM




Top of Page | View New Posts