dishwasher/disposal/refrigerator wiring, NEC

Hi there,

Have a couple of questions on wiring requirements and options on dishwasher/disposal/refrigerator.

1. Wonder where I can locate the latest minimum NEC requirements online for the wiring of these above items.


2. For Dishwasher/Disposal,

Is it an NEC requirement to have a dedicated circuit for each?

Additional ideas:
2a. Option 1

- Dishwasher : dedicated 15A circuit
- Disposal : on a shared 20A circuit

The disposal is rating 6A. Can I -- for example, put the disposal on a 20A circuit -- that's shared with the other receptacles along the same side of the kitchen wall? Is that still considered compliant with NEC requirement?

2b. Dishwasher + Disposal on a single 20A circuit (no other shared)

The dishwasher has the rating:
motor 6.5A
heater 5.0A
max load: 11.0A

Would this break the NEC requirement?


3. For the refrigerator,

if the label states 15A rating, is is safe to put it on a dedicated 15A circuit, or current surge during startup would cause > 15A current and would cause a trip on the 15A breaker I so I should put it on a 20A circuit? Which is the right size for NEC requirement?


Thx.

 

Take a look at Chapter 37 - Branch Circuit and Feeder Requirements and Chapter 37 - Branch Circuit and Feeder Requirements

 

Welcome to the forums!

First of all, all codes is local. We can discuss the NEC requirements, but what matters is the regulations your jurisdiction has adopted, and how they interpret those regulations. That said,

There is no "right size" requirement for the refrigeration equipment circuit. The NEC requires that it be served by one of the small appliance branch circuits, then makes an exception to allow a dedicated circuit. A 15A breaker should be able to handle the startup load without tripping.

Does the label actually state 15A as the load (very unusual) or 15A as the minimum overcurrent protection?

There is no size requirement in the NEC for the circuits serving the dishwasher and the disposal. One common solution is to run a multi-wire branch circuit protected by two 15A breakers (joined with a handle tie) and use one for each appliance.

You can't. The NEC is a proprietary publication. If you want a copy you have to buy one.

Ask your local jurisdiction for a copy of their regulations. For one thing, that will tell you which cycle of the NEC they have adopted, in whole or in part. Plus the other regulations they have that will control their interpretation of the NEC - assuming they are adopting the NEC at all.

 

There is no Chapter 37 in the NEC. Referring to the "2012 International Codes" does not answer a question about NEC requirements, nor about the requirements of any jurisdictions that haven't adopted the provisions of the International Code.

Offhand, I'm unaware of any that have.

 

I figured the IRC would be a starting point as it is a lot easier to read and is available on line to all.

The OP shows in California which has its code online. And as you inferred, still would need to check with for local amendments. RealRead Viewer : California*Electrical*Code*2010

 

Yes you can..

2008: NFPA 70: National Electrical Code®

2011: NFPA 70: National Electrical Code®

You can READ the two latest editions (2008 and 2011 as of now) online at the above link. You just have to sign up for an account (free, but you have to agree to be inundated with spam and paper junk mail from NFPA), and have Java on your machine. Their program is a READER only. You can not print, save, or copy/paste from it, but it's good for quick lookups.

 

You can print using the snipping tool

 

What a great resource to know about and to be able to share!

Thanks, Matt. This is one of those times I really enjoy being corrected / enlightened. Paging through that "RealRead" document is tedious and I didn't see any way to search or clikck through be section. But it's there, in its entirety.

NOTE: You only have to agree to be inundated with spam and paper junk mail from NFPA if you don't opt out of their default settings. As far as I could tell there was no requirement that you accept any of their suggestions.

 

Astuff, the OP asked specifically about NEC requirements. In addition, he's asking about requirements for electrical work in California. How is the IRC (whatever that is) relevant to that?

Now that's relevant!

 

The IRC is the International Residential Code witch includes a modified NEC along with other codes but is usually one year late in version. There are only a few states that use it (such as my home Pennsylvania). I do find it easier to read than the raw NEC and anyone can get to it without an account is a bonus. As you said "most codes are local" so until you track down the AHJ it is only an educated guess as to which codes apply.

 

Yep. What I actually said is all codes is local. The only code that applies is the one adopted by the jurisdiction you're working in. They may have adopted the 2011 NEC in whole or in part, still be using the 2008 NEC in whole or in part, be using the NEC with additional provisions which they drafted, or simply be using something that's entirely theirs.

As of July 1, 2012, both California and Pennsylvania had adopted the 2008 NEC statewide.

As of December, 2012, both California and Pennsylvania had adopted the 2009 IRC statewide.

I emphasized statewide because the local jurisdiction may have any number of modifications to what the state has done.

 

I am confused about NEC [210.21(B)(2)]

"If a branch circuit supplies two or more receptacles,
the total cord-and-plug connected load must not exceed 80% of the receptacle rating."


Is a duplex receptacle considered two receptacles?


If so, then a 6Amp disposal + 11Amp dishwasher = 17Amp total current rating. It'd be higher than the allowed 80% load (16Amp) on a 20Amp circuit.


Is that true?

 

The disposer is not considered a continuous load. Therefore you can run both the dishwasher and the disposer on one dedicated 20 amp circuit. It can not feed or be connected to the counter top receptacles.

I have both of mine on a single 20 amp circuit and have not had a single issue in 20 years.

 

So NEC [210.21(B)(2)] is not violated in this case?

Both the disposal and the dishwasher are fastened in place, but are also cord-and-plug connected.

 

Many dishwashers and disposals nowadays come with cord and plug applications, just for that reason. Saves a bunch of hardwiring. If they don't it is not against code to install SOJ cable to the unit for a plug in application. Ideally the receptacle is split and half is energized via a switch for the disposal and the other half is constantly hot for the dishwasher.

 

The only thing I'm concerned is the 80% rule in NEC [210.21(B)(2)] -- which seems to apply to non-continuous load also.

 

But that says a receptacle and if you use a duplex receptacle then each of those two receptacles incorporated into a duplex receptacle is a receptacle with that rating.

 

Ahh,

so the NEC [210.21(B)(2)] 80% rule applies to each receptacle only and not the circuit.

 

Bingo!!!!!!!!!...........................

 

Just talked to the city office on the circuit for disposal and dishwasher, and they quoted the 50% rule in 210.23(A)(2).

"The total rating of utilization equipment fastened in place, other than Luminaires (lighting fixtures), shall not exceed 50% of the branch-circuit ampere rating

where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied."


I mentioned it's a dedicated circuit w/ only disposal and dishwasher, and both equipment are fastened in place.


The person didn't seem to fully understand the NEC code (he browsed thru' the code for a while), and went to his supervisor for answer.


He came back with this:

"This is the way we interpret the code. The 50% rule applies to any kind of equipment. As long as there's more than one equipment on the circuit the 50% rule applies to each equipment."


Sound a bit bizarre, as it seems NEC makes a clear distinction between fastened and non-fastened equipment.

 

That refers to a circuit that is not dedicated. On a dedicated circuit you do not have "where lighting units, cord-and-plugconnected
utilization equipment not fastened in place, or
both, are also supplied.". In kitchens that code is most commonly applied to built in microwave ovens with an exhaust hood.

 

The circuit serves only disposal and dishwasher. 210.23(A)(2) would (should?) still apply?

 

No, it should not apply. See my explanation above. Unfortunately it is whatever the inspector says if you don't want a hassle. At this point I might run two 15 amp circuits and install two 15a simplex receptacles in a two gang box.

 

It almost certainly would if they were both hardwired. How big a fight do you want to have? If you do the two-circuit/two-simplex-receptacle trick that Ray suggested, it'll not only pass, it will make wiring the switch for the disposer easier.

 

They're both cord-connected--don't know if that matters for 210.23(A)(2).

This person simply said, "That's the way we do it." It didn't seem to indicate he knew what he was talking about. I wonder if I call the city next week another person might give me a different answer.


The main reason being I'm running out of slots on my old 100A main panel. Sigh, will have to find a way out... .

 

You could add a subpanel.