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#94719 - 07/06/05 01:41 AM disposer/dish circuit  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
Washington...Not DC
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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#94720 - 07/06/05 12:39 PM Re: disposer/dish circuit  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,099
Estero,Fl,usa
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

#94721 - 07/07/05 02:12 AM Re: disposer/dish circuit  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
Washington...Not DC
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


#94722 - 07/07/05 12:39 PM Re: disposer/dish circuit  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,099
Estero,Fl,usa
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

#94723 - 07/07/05 10:03 PM Re: disposer/dish circuit  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
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.


#94724 - 07/12/05 09:46 PM Re: disposer/dish circuit  
Larry Fine  Offline
Member
Joined: Feb 2005
Posts: 693
Richmond, VA
"...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

#94725 - 07/12/05 09:55 PM Re: disposer/dish circuit  
Larry Fine  Offline
Member
Joined: Feb 2005
Posts: 693
Richmond, VA
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

#94726 - 08/10/05 09:27 AM Re: disposer/dish circuit  
dlhoule  Offline
Member
Joined: Apr 2005
Posts: 73
Saline, MI 48197
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?


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


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


Ryan Jackson,
Salt Lake City

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