Dishwasher/Disposal 3-wire circuit to duplex

[e57]

Just looked up 'GE' top of the line dishwasher 9.1amps.

First I have seen in some time...

The 'top of the line' appliances generally require less amperage. The low-end ones use more. But that's just a 'rule of thumb', not set in stone.

I have found that to be the opposite...
Bosch is 12A
Thermador is 12A
Miele even has one at 240 30A!

As mentioned the GE he mentions is the lowest I have seen in some time. And still:

Electrical Requirements​

? This appliance must be supplied with 120V, 60Hz., and
connected to an individual properly grounded branch circuit
protected by a 15 or 20 ampere circuit breaker or time delay
fuse.​

http://products.geappliances.com/Ma.../Dispatcher?RequestType=PDF&Name=31-30588.pdf

 

[e57]

So even then - coupled with a garbage disposal on the upper end of the market often at 10A itself you could easily push over 20A.

Insinkerator - 10.2A

Or:

Kitchen Aid:

? If junction box is used, connect the junction box to the
switch on a separate 15 or 20 Amp. 115 Volt circuit with
the appropriate cable (Use 14 gauge wire with 15 Amp​

circuit, and 12 gauge wire with 20 Amp circuit.)

And as mentioned before - a 20A circuit - cord connected is limited to 16A...

Why is it that some want to blindly run a single circuit for both, and still some of those only a 15A at that? Sure - you could if the spec's are iron clad, but as we all know spec's change at random - why not CYA and run a 14/3 at the bare min. if not 12/3? At the cost of a roll of dimes - why not? For that matter bill for it standard... Locally 12/3 (two 20's) is the standard install, along with a dedicated for the fridge (usually a sub-zero), stove, hood and micro - as well as the two CT circuits.

 

[480sparky]

Kind of like those Cadillacs use less gas, rule of thumb ?

No. More money=better engineering. Better engineering=higher quality. Higher quality=less amps. Less amps=a better label to advertise with.

 

[e57]

No. More money=better engineering. Better engineering=higher quality. Higher quality=less amps. Less amps=a better label to advertise with.

I find the opposite - More money - higher performance. Higher performance - over-built. Over built high performance - higher amperage. If Hummer or Land Rover made appliances they would be all over it... And people who buy this stuff could care less about cost or efficiency - they want it to do the job the first time no matter the cost. The last two kitchens I have done have had two dishwashers, and 2-3 disposals - and neither of the couples cook, they have slaves/maids do that...

 

[480sparky]

I find the opposite - More money - higher performance. Higher performance - over-built. Over built high performance - higher amperage. If Hummer or Land Rover made appliances they would be all over it... And people who buy this stuff could care less about cost or efficiency - they want it to do the job the first time no matter the cost. The last two kitchens I have done have had two dishwashers, and 2-3 disposals - and neither of the couples cook, they have slaves/maids do that...

Going 'green' is the next big thing. Look at people buying furnanes these days. You think they'll happily accept an 80% unit? No, they want at 96 or 97%.
Everyone looks at the effeciency labels these days. And the more expensive an appliance is, the more effecient it is.

 

[e57]

Going 'green' is the next big thing. Look at people buying furnanes these days. You think they'll happily accept an 80% unit? No, they want at 96 or 97%.
Everyone looks at the effeciency labels these days. And the more expensive an appliance is, the more effecient it is.

Not always true - And going "green" should mean we would be installing few recessed cans - but that is also not the case. "Green" is hemp and beeswax candles... The "green" thing is like fashion people wear to impress IMO. Many will easily set aside efficiency and fashion for luxury - we are talking about dishwashers are we not? "Green" would mean Jimmy Carter's sweater, composting, dish-pan hands, and drying clothes in the sun after beating them in your bath water....

 

[480sparky]

Not always true - And going "green" should mean we would be installing few recessed cans - but that is also not the case. "Green" is hemp and beeswax candles... The "green" thing is like fashion people wear to impress IMO. Many will easily set aside efficiency and fashion for luxury - we are talking about dishwashers are we not? "Green" would mean Jimmy Carter's sweater, composting, dish-pan hands, and drying clothes in the sun after beating them in your bath water....

Well, I'm glad all your customers are so filthy stinking rich they can easily afford to not care about the effeciency of the stuff they buy.
Then there's the rest of us.

Which is more energy effecient, a Prius or a Kia? And which one costs more?

 

[e57]

Which is more energy effecient, a Prius or a Kia? And which one costs more?

Some would say the Kia.... Some even say the Hummer.... The Kia - No recycling of hazardous batteries, less toxic and fuel consuming to actually build it, and not too dramatically different in mileage... But boy are they fashionable...

http://www.dosomething.org/blog/chatterbox/prius-not-so-green-afterall
http://www.wired.com/science/planetearth/magazine/16-06/ff_heresies_09usedcars

As for the wealth of customers - I treat the rich ones just the same as I do the poor ones. And all the poor ones want is what the rich ones have. If the rich ones have Ferraris that wash dishes - the poor ones just want a knock off brand of the same... Point is - While a GD is only on for a short time, and would normally not trip the circuit - putting both a 10+A GD and DW on a 15a circuit is an over-load condition. If it did trip - the rich one and the poor one would both look at me funny...

 

[Greg1707]

dishwasher/disposer on single cirucit

dishwasher/disposer on single cirucit

There is a certain instance in which installing the dishwasher and disposal on a single 20 amp circuit is the way to go. This a retro fit job where someone is adding a dishwasher to a finished kitchen and there is no space left in the panel. If the existing disposal is on a 20 amp circuit and care is taken to purchase a dishwasher 10 amps or less, ripping up the customer house can be avoided.

 

[220/221]

Obviously, there are different approaches to wiring the kitchen appliances.

Here, the standars is and has been one 20 amp circuit for DW/Disp. ONE time, I had an inspector ask for the cut sheet for the appliances. I guess there are some new models that draw more than 10 amps.

What is the advantage of the cord and plug method described in the original post vs. just hard wiring the dishwasher/disposal.

Ease of installation/replacement along with code compliant disconnect. 3 wire from disposal switch to 1/2 switched recep under the sink cabinet is our standard method. Then, put the cords on the appliances before they are installed.

 

[Ragin Cajun]

Just checked the relatively new ones in my house:

Disposal: 6.7A

Dishwasher: 936A

Don't forget, the above are not continuous loads.

Two door frig (brand new) 6.5A

Two door frig (~10 yrs old) 6A




I do a lot of section 8 (subsidized) apartments and use a split duplex receptacle with 14/3 and a 2 pole 15A breaker to play it "safe".


RC

 

[LarryFine]

Dishwasher: 936A

That's one heck of a dishwasher!

 

[480sparky]

That's one heck of a dishwasher!

Tim Taylor special........ "MORE POWER!" (Insert your own simian grunts here)

 

[Ragin Cajun]

TYPO!

That's 9.6a

Sorry about that!


RC

 

[LarryFine]

TYPO!

That's 9.6a

Sorry about that!

That's okay, I was just funnin' ya. (We don't miss anything around here. )

 

[e57]

Just checked the relatively new ones in my house:

Disposal: 6.7A
+
Dishwasher: 9.36A
=16.06A Total connected load.

Don't forget, the above are not continuous loads.

RC

If on one 20A circuit, and cord connected you would be .06A over due to 210.21(B)2 - sure it's not much - but.... :roll:

 

[mka]

Clarification

Clarification

So even then - coupled with a garbage disposal on the upper end of the market often at 10A itself you could easily push over 20A.

Insinkerator - 10.2A

Or:

Kitchen Aid:


And as mentioned before - a 20A circuit - cord connected is limited to 16A...

Why is it that some want to blindly run a single circuit for both, and still some of those only a 15A at that? Sure - you could if the spec's are iron clad, but as we all know spec's change at random - why not CYA and run a 14/3 at the bare min. if not 12/3? At the cost of a roll of dimes - why not? For that matter bill for it standard... Locally 12/3 (two 20's) is the standard install, along with a dedicated for the fridge (usually a sub-zero), stove, hood and micro - as well as the two CT circuits.

E57,

This is a two part question:

1) First my setup: Both the dishwasher and disposal are cord connected on a duplex receptacle with the tab broken sharing the neut. from 12/3 feed from panel with 2 pole 20A OCPD.

Dishwasher: Eurotech = 12A
Disposal: Insinkerator = 8.1A

When trying to figure the loads for this setup I am somewhat confused from the earlier posts on this thread. If 12/3 has been ran as stated above, the two above amperages are not additive making it 20.1A but on separate 20A circuits with that 2 pole circuit breaker.

In other words, the dishwasher is separate circuit for 12A and the disposal is separate circuit for 8.1A making them well under the safe requirements for the 16A cord connected requirement. Which brings me to my second question.

2) I guess it is the breaker that is confusing me with this setup. Could you please explain electrically how the two would share the neutral back to the circuit breaker? Is the two pole breaker acting like two separate 20A breakers for two separate circuits?

Thanks,

Mka

 

[LarryFine]

2) I guess it is the breaker that is confusing me with this setup. Could you please explain electrically how the two would share the neutral back to the circuit breaker? Is the two pole breaker acting like two separate 20A breakers for two separate circuits?

Yes, it is. Read this: http://forums.mikeholt.com/showpost.php?p=708650&postcount=4

 

[mka]

Further clarification of neutral

Further clarification of neutral

Larry, i read the link you posted directed to Dennis and it helped. However,
I'm still a bit confused as to current returning on the neutral. So for example, if I take my voltmeter and apply both leads to an energized 120V receptacle I will read 120V. How much of that 120V is returning to the source on the neutral and when?

Also, in that earlier post you said,

"Originally Posted by Dennisc
I guess a neutral would be like on a 220 v 3 wire hot water heater. Black and red hot, then white neutral. Sound Right? This type of "neutral" is what would handle the imbalance.
Dennis, you just happened to pick the wrong type of appliance as an example, because a water heater uses the two hot wires only. The heating elements are rated at 240v, there are no 120v components in a water heater, so a 2-conductor + g. cable is appropriate.

Now, a clothes dryer is the perfect example, because while the heating element is rated at 240v, and connects line-to-line, but the drum and timer motors are rated for 120v, and connect from one line conductor to the neutral. A 3-conductor + g. cable is called for.

So, for a dryer, both lines would carry the heater current; in addition, one of the lines and the neutral would carry the motor loads. If the heater is 20a and the motors total 5a, then one line would carry 20a, one line would carry 25a, and the neutral would carry 5a."
__________________
Code references based on 2005 NEC
Larry B. Fine
Master Electrician
Electrical Contractor
Richmond, VA

In the case of the 240V appliance with no neutral, how do the electrons flow back to the source?

Mka,

LU 595, apprentice

 

[hurk27]

First you must envision a secondary of a 240/120 volt center tap transformer,
now connect your two load on each side of the center tap, so that you have one load from A leg to neutral, and the other load from B leg to neutral, now note that these two loads are also in series with the 240 volts of A and B leg, with the neutral retaining the balance to the center tap, so with the 8.1 amp load all of it will flow back to the other leg through the series connection of the 12 amp load, but the 12 amp load can only flow 8.1 amps back through the other load, so the imbalance of the current left over will flow on the neutral, which would be 3.9 amp.

only if these two circuits were on the same leg would they be an additive.

Also all appliances or equipment requiring over 12 amps would have a 20 amp cord, not a 15 amp, this is why it would be ok with the NEC for these two items to be placed on there own 15 amp circuit. whether it be a multi-wire or single run circuits both would be code.