Breaker use

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  #1  
Old 11-24-04, 08:54 AM
efce
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Breaker use

I'm installing a dishwasher and a garbage disposal. I need to run power to them from a breaker box. I believe I should power each separately through 20 amp breakers. However, a spare unused ganged 30 amp breaker is available. Would it be OK to supply power to the dishwaser and garbage disposal through separate sides of the ganged breaker? Or should I replace the ganged 30 amp breaker with 2 separate 20 amp breakers? There is no room for 2 additional breakers. efce
 
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  #2  
Old 11-24-04, 09:12 AM
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Location: Fayetteville, NY, USA
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What I see most commonly is both appliances on a single 20 amp circuit. They are usually cord-and-plug connected to a receptacle inside the sink cabinet, with no other receptacles or equipment on that circuit.

The NEC says that any fixed in place equipment (DW and disposal qualify) cannot draw more than half the circuit's rating. Disposals are generally the following standard sizes, in horsepower (HP)

1/4 (5.8 amps); 1/3 (7.2 amps); 1/2 (9.8 amps).

If you ran a 20 amp circuit, on a 1-pole breaker, you can see that a disposal wouldn't be greater than 50% of the circuit's rating.

There should be a metal nameplate on your dishwasher listing the FLA (Full Load Amps) of the unit. It's usually visible if you remove the "skirt" panel below the door. Sometimes you can find it in the owner's manual, too. Depending on your dishwasher's amperage rating, you may be able to run both appliances from one 20 amp 1-pole breaker. In this case, I would replace your 30 amp, 2-pole breaker with 2 20 amp breakers, one for this circuit and one for a future circuit if you need it.

I can't think off hand if two 120 volt circuits can share a "ganged", or 2-pole breaker, according to the NEC. But I generally hear words of discouragement toward this practice under most circumstances, particularly in residential situations. I know I wouldn't do it. Not the least of good reasons is the potential confusion of a future homeowner believing it is a 220 volt circuit.

So check the amperage of your disposal and dishwasher and consider this option.

Also, there is a particular way you wire the disposal side of the duplex receptacle. It is simple, but necessary so that you can switch the disposal on & off. Posting in this forum will easily get you the instructions.

Hope that helps.

Juice
 
  #3  
Old 11-24-04, 11:56 AM
efce
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Juicehead

Thanx! I'll go with 2 20s.
Wonder if I'll have trouble finding the breakers...the house was built in 1960.
efce
 
  #4  
Old 11-24-04, 11:58 AM
efce
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Breaker use

Thanx! I'll go with 2 20s.
Wonder if I'll have trouble finding the breakers...the house was built in 1960.
efce
 
  #5  
Old 11-24-04, 12:05 PM
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Location: Fayetteville, NY, USA
Posts: 1,052
Open your electrical panel and look for the manufacturer's name and the model number. If it is a non-major brand the folks in here can help you find new breakers for it.

I think the 20 amp spare will come in handy some day. Make sure you use #12 wire on 20 amp breakers. #14 wire can only be used on 15 amp breakers.

Juice
 
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