another disposal dishwasher question

Status
Not open for further replies.
lets be realistic here for one second. Im looking to save some serious coin for my company. Ive got over 200 apt no larger than 800 sq. ft. I want to put the dishwasher and the disposal not only on the same circuit, but use the same outlet. under the sink. That will save me 200 breakers 200 4 sguare bx 200 recp. and the wire. (originally I had put on a dedicated) I know this has been asked already. But the savings will be huge. I have my mind made up. With a show of hands has anybody really done this. And did it cause any problems. I done the math, and yes its close. But I loose more sleep at night by having the refer on the small app.
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
i've seen it done many times and have actually had inspectors request that i do it that way. go ahead; be the hero. :D
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I see no problem providing the two appliances fall below the 50% circuit loading threshold.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
infinity said:
I see no problem providing the two appliances fall below the 50% circuit loading threshold.

I believe most dishwashers draw over 10 amps-- at least they use to-- this would make adding the disposal to it illegal however, I can't imagine it being a problem since disposals are on for secs. Someone should write a proposal to make a change on this.

Anyway it may not be legit but I would certainly ask the inspector before I did something like that.

You can put the disposal on with some lighting and not worry about it. That is what I do. 15 amp circuit-- hit the kitchen lights and then the disposal.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Actually I just read some specs on a Bosch dishwasher and it says you can use a 15 amp circuit but it also states it to be dedicated.
 

kbsparky

Senior Member
Location
Delmarva, USA
As pointed out, the operation of a disposal unit is only for a few seconds at a time. It seems wasteful (pun intended) to have a dedicated circuit for such an intermittent load.

Depending on your local inspector-critter, you might be able to install both appliances on the same 20 Amp circuit.I've never heard of any incidences of places burning up from such an arrangement.

An alternative might be a back-door trick: Install a 3-way switch for your control of the disposal. Wire it up so that the "up" position sends power to the disposal, and the "down" position would send power to the dishwasher. Doing so would temporarily disconnect power from the dishwasher while the disposal unit is operating. Then you would have the luxury of declaring "non-conincident loads" and could even use a 15 Amp circuit, saving on wire costs as well. :D

Since you are planning to use a cord-and-plug method of final connection to each appliance, the switch does not need to be the indicating type.:smile:
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I think that if your math shows it to be "fine," however close that might be to "not fine," then it is acceptable. This is not a situation in which the code requires additional margin (such as the 25% for continuous loads).

But just for the sake of amusement, and in case your inspector tells you in advance he or she won't accept it, how badly would it impact the cost to use #10 wire and either a 25 or 30 amp breaker?
 

1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
Dennis Alwon said:
... You can put the disposal on with some lighting and not worry about it. That is what I do. 15 amp circuit-- hit the kitchen lights and then the disposal.

If you have two different circuits on the same yoke, the duplex, you would need to use a handle tie to open both circuits. Yes / No?
 

LawnGuyLandSparky

Senior Member
charlie b said:
I think that if your math shows it to be "fine," however close that might be to "not fine," then it is acceptable. This is not a situation in which the code requires additional margin (such as the 25% for continuous loads).

But just for the sake of amusement, and in case your inspector tells you in advance he or she won't accept it, how badly would it impact the cost to use #10 wire and either a 25 or 30 amp breaker?

Another out - using a push-and-hold momentary contact switch, and I see Lowes stocks these in the decora style.
 

tallguy

Senior Member
Cavie said:
Just put them both on one 20 circuit and don't worry about it.
Best to check w/ the AHJ, or be certain that whatever is to be installed for the dishwashers is below 10A.

If he runs afoul of 210.23(A)(2) (as Trevor & Dennis mentioned above) and the inspector calls them on it, he would most definitely not be the hero. :smile:

I would think that a conscientious inspector might turn a blind eye to 210.23(A)(2) for addition of a dishwasher to a one-off home remodel, but why would they knowingly do so on a 200 apartment project??
 

Cavie

Senior Member
Location
SW Florida
tallguy said:
Best to check w/ the AHJ, or be certain that whatever is to be installed for the dishwashers is below 10A.

If he runs afoul of 210.23(A)(2) (as Trevor & Dennis mentioned above) and the inspector calls them on it, he would most definitely not be the hero. :smile:

I would think that a conscientious inspector might turn a blind eye to 210.23(A)(2) for addition of a dishwasher to a one-off home remodel, but why would they knowingly do so on a 200 apartment project??

210.23 A 2 is not an issue. no lighting outles. both units are fastened in p;ace. Nothing but the DW and disposol.
 

tallguy

Senior Member
Cavie said:
210.23 A 2 is not an issue. no lighting outles. both units are fastened in p;ace. Nothing but the DW and disposol.
Ah... yes... ahem..... ermmmm... looks like I stumbled on "fastened in place".


<about face>

infinity said:
I see no problem providing the two appliances fall below the 50% circuit loading threshold.
How does that apply here?
 

lpelectric

Senior Member
charlie b said:
I think that if your math shows it to be "fine," however close that might be to "not fine," then it is acceptable. This is not a situation in which the code requires additional margin (such as the 25% for continuous loads).

But just for the sake of amusement, and in case your inspector tells you in advance he or she won't accept it, how badly would it impact the cost to use #10 wire and either a 25 or 30 amp breaker?

I think this is a great idea! :smile: Kudos to Charlie B
 

haskindm

Senior Member
Location
Maryland
I see no problem with this installation. What you have is TWO fastened in place appliances on one circuit, which is a situation not addressed in 210.23. It does say that ONE fastened in place appliance shall not exceed 80% of the ampacity of the circuit, so the dishwasher does not exceed 80%. Table 210.24 shows that a 20-amp circuit Maximum Load is 20-amps. As long as you have not exceeded a 20-amp load, it appears to be no problem. I can imagine some inspectors having a problem with it, but I cannot find a code section that would prohibit it.
 

iwire

Moderator
Staff member
Location
Massachusetts
charlie b said:
how badly would it impact the cost to use #10 wire and either a 25 or 30 amp breaker?

Could be a violation of 422.11(A).

Also the poster said he was planing on cord and plug connection, I doubt DW or DISP manufacturers make a appliance cord with a 30 amp cord cap for those units.
 

haskindm

Senior Member
Location
Maryland
210.24 indicates that a 30-amp circuit requires 30-amp receptacles, so I don't see how that would work. There is no 25-amp circuit identified in 210.24, so I don't know how that would be treated, and 210.3 does not list 25 amp as being one of the acceptable multi-outlet branch circuits.
 

480sparky

Senior Member
Location
Iowegia
iwire said:
Could be a violation of 422.11(A).

Also the poster said he was planing on cord and plug connection, I doubt DW or DISP manufacturers make a appliance cord with a 30 amp cord cap for those units.

As well as Table 210.24. You can't use 15- or 20-a receps.
 

wbalsam1

Senior Member
Location
Upper Jay, NY
Please let me pose a hypothetical here for the purpose of learning something. Feel free to cite code violations.....

but what would be the matter with running a 10/2 with ground NM cable from the panelboard and fused at 20 amperes to a junction box mounted beneath the kitchen sink and tapping #12/2 wg off to a single receptacle rated at 20 amperes for the 4' cord of the dishwasher to plug into, and another 12/2 tap just like it for the disposal?

....I've never done this and only thought of it today after Charlie B's post. :smile: I'll hang back and take my lumps....:D



edited to 20 amperes
 
Last edited:

480sparky

Senior Member
Location
Iowegia
Nothing wrong with that at all. I'd say you were just concerned about voltage drop. But remember, it's still a 20amp circuit.
 
Status
Not open for further replies.
Top