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disposer/dish circuit
#154392
07/06/05 12:41 AM
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Joined: Mar 2005
Posts: 236
OP
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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.
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Re: disposer/dish circuit
#154393
07/06/05 11:39 AM
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Joined: Jul 2004
Posts: 9,555
Member
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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
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Re: disposer/dish circuit
#154394
07/07/05 01:12 AM
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Joined: Mar 2005
Posts: 236
OP
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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
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Re: disposer/dish circuit
#154395
07/07/05 11:39 AM
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Joined: Jul 2004
Posts: 9,555
Member
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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
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Re: disposer/dish circuit
#154396
07/07/05 09:03 PM
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Joined: Jan 2005
Posts: 5,316
Cat Servant Member
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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.
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Re: disposer/dish circuit
#154397
07/12/05 08:46 PM
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Joined: Feb 2005
Posts: 693
Member
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"...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
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Re: disposer/dish circuit
#154398
07/12/05 08:55 PM
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Joined: Feb 2005
Posts: 693
Member
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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
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Re: disposer/dish circuit
#154399
08/10/05 08:27 AM
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Joined: Apr 2005
Posts: 73
Member
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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?
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Re: disposer/dish circuit
#154400
08/10/05 09:23 AM
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Joined: Oct 2004
Posts: 135
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Any 3-way rated for the load would work.
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Re: disposer/dish circuit
#154401
08/10/05 04:43 PM
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Joined: Aug 2003
Posts: 1,374
Moderator
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I am moving this to the NEC section.
Ryan Jackson, Salt Lake City
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