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disposer/dish circuit #94719
07/06/05 12:41 AM
07/06/05 12:41 AM
watersparkfalls  Offline OP
Member
Joined: Mar 2005
Posts: 222
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.

2017 / 2014 NEC & Related Books and Study Guides
Re: disposer/dish circuit #94720
07/06/05 11:39 AM
07/06/05 11:39 AM
G
gfretwell  Online Content

Member
Joined: Jul 2004
Posts: 9,166
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
Re: disposer/dish circuit #94721
07/07/05 01:12 AM
07/07/05 01:12 AM
watersparkfalls  Offline OP
Member
Joined: Mar 2005
Posts: 222
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

Re: disposer/dish circuit #94722
07/07/05 11:39 AM
07/07/05 11:39 AM
G
gfretwell  Online Content

Member
Joined: Jul 2004
Posts: 9,166
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
Re: disposer/dish circuit #94723
07/07/05 09:03 PM
07/07/05 09:03 PM
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.

Re: disposer/dish circuit #94724
07/12/05 08:46 PM
07/12/05 08:46 PM
L
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
Re: disposer/dish circuit #94725
07/12/05 08:55 PM
07/12/05 08:55 PM
L
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
Re: disposer/dish circuit #94726
08/10/05 08:27 AM
08/10/05 08:27 AM
D
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?

Re: disposer/dish circuit #94727
08/10/05 09:23 AM
08/10/05 09:23 AM
B
BobH  Offline
Member
Joined: Oct 2004
Posts: 135
Newfane, N.Y USA
Any 3-way rated for the load would work.

Re: disposer/dish circuit #94728
08/10/05 04:43 PM
08/10/05 04:43 PM
R
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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