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disposer/dish circuit #94719 07/06/05 01:41 AM
Joined: Mar 2005
Posts: 233
watersparkfalls Offline OP
Member
i want to know if anybody can help me calculate if i can put a 1/2 HP disposer motor and a dishwasher that draws a nameplate or 9.1 amps on a 20 amp circuit.

2017 / 2014 NEC & Related Books and Study Guides
Re: disposer/dish circuit #94720 07/06/05 12:39 PM
Joined: Jul 2004
Posts: 9,389
G
gfretwell Offline
Member
Nominal FLA on a 1/2 HP motor is 9.8a (plus 25%) added to 9.1a seems to be too much for a multiple motor load.
If you are cord and plug connected they each do represent less than 50% of circuit ampacity so it might be "hold your nose" legal. I have seen this go both ways but the preferable solution is a multiwire circuit with 2 phases feeding the duplex.


Greg Fretwell
Re: disposer/dish circuit #94721 07/07/05 02:12 AM
Joined: Mar 2005
Posts: 233
watersparkfalls Offline OP
Member
thanks gf i just wondered if possible...
could you elaborate on the 50% since cord connected dishwashers are feasible and do provide disconnecting means for motor.

h2o

Re: disposer/dish circuit #94722 07/07/05 12:39 PM
Joined: Jul 2004
Posts: 9,389
G
gfretwell Offline
Member
It all gets down to how you read
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.

Most inspectors would say all fixed in place equipment must be less than 50% but I have seen this stretched to say any one piece can't exceed 50%, particularly on an intermittant load like a disposal.
Vote me for "all".


Greg Fretwell
Re: disposer/dish circuit #94723 07/07/05 10:03 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
Member
One caution here....look at the FLA on the disposal, and not the "horsepower" rating. I have seen a lot of inflated "horsepower ratings" over the years.

Re: disposer/dish circuit #94724 07/12/05 09:46 PM
Joined: Feb 2005
Posts: 693
L
Larry Fine Offline
Member
"...lighting units (or) cord-and-plug-connected utilization equipment not fastened in place..."

Neither describe either a dishwasher or a disposer, so 210.23(A)(2) doesn't apply.

I routinely place both of these on a 20-amp circuit. A disposer is probably the epitome of an intermittent load.


Larry Fine
Fine Electric Co.
fineelectricco.com
Re: disposer/dish circuit #94725 07/12/05 09:55 PM
Joined: Feb 2005
Posts: 693
L
Larry Fine Offline
Member
According to Insinkerator specs, the 1/2HP Badger 5 has an average current draw of 6.9A.
http://www.insinkerator.com/pdf/badger5.PDF


Larry Fine
Fine Electric Co.
fineelectricco.com
Re: disposer/dish circuit #94726 08/10/05 09:27 AM
Joined: Apr 2005
Posts: 73
D
dlhoule Offline
Member
Good subject. I have been told that they make a 3 way switch that can be used in these applications. One position for dishwasher and other for disposal. Now having said that I personally have not seen one. Do they make them?

Re: disposer/dish circuit #94727 08/10/05 10:23 AM
Joined: Oct 2004
Posts: 135
B
BobH Offline
Member
Any 3-way rated for the load would work.

Re: disposer/dish circuit #94728 08/10/05 05:43 PM
Joined: Aug 2003
Posts: 1,374
R
Ryan_J Offline
Moderator
I am moving this to the NEC section.


Ryan Jackson,
Salt Lake City
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