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I couldn't find a direct up-to-date answer. For example the comments on this answer contradict each other.

So, which of the following kitchen appliances are allowed to be grouped onto the same 20A circuit (USA)?

  • Fridge
  • Microwave (built-in)
  • Range hood
  • Dishwasher
  • Garbage disposer
  • Under-cabinet lights
ybungalobill
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    The question and comments are 9 years old. At the time NEC 2011 wasn’t deployed yet. **So those answers are based on NEC 2008, which is 5 editions ago** and they’ve really been changing stuff in the kitchen. The comments aren’t contradictory, Code was changing. – Harper - Reinstate Monica Jul 09 '20 at 02:25
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    Which of these appliances is cord-and-plug connected? What is the nameplate amperage on the microwave, dishwasher and garbage disposal? Is your ultimate goal to have a highly functional kitchen that doesn’t have nuisance trips or require appliance juggling to cook a decent meal? – Harper - Reinstate Monica Jul 09 '20 at 02:40
  • Also, do you have any plans for a generator? And yes, can you get us information about what appliances you're using? (Such as nameplate ratings and whether stuff's hardwired or cord-and-plug connected) – ThreePhaseEel Jul 09 '20 at 02:46
  • @Harper-ReinstateMonica: Yes, I'm aware of this and this is why I'm asking for an up-to-date information. My current project will have only three of the mentioned appliances, but I am interested in some degree of future-proofing. I'm aware of the implications of putting multiple appliances on the same circuit, and more than capable to calculate the wattage. There are other considerations other than running more wires. My ultimate goal is to understand the current code POV to find the best compromise in this and future situations. – ybungalobill Jul 09 '20 at 02:57
  • @ThreePhaseEel: No generator. How would it change anything? – ybungalobill Jul 09 '20 at 02:57
  • Mot people like to be able to cook something with the power out, and not have all the food in the fridge rot. – Ecnerwal Jul 09 '20 at 03:09
  • @ybungalobill -- generally, people with generators want to be able to use the generator to power the fridge during a utility outage – ThreePhaseEel Jul 09 '20 at 03:19
  • @ybungalobill -- are you limiting yourself to NM cable here, or are you open to other wiring methods? Do you have a kitchen island in your plans for that matter? Finally, are breaker spaces a constraint for you at all? – ThreePhaseEel Jul 09 '20 at 03:21
  • @ThreePhaseEel: Oh, I'd never experienced long power outages so it didn't cross my mind. Besides we don't need fridges for half the year here :) I'm wiring with NM right now, but other wiring methods are an option. Breaker spaces are one of the variables in the equation. I don't have an island, but again, I'm not sure how it is relevant. E.g. if the code allows combining a fridge with a hood, but only if I'd be using armored cable, and only during full moon, then I'd like to see that explained in an answer. – ybungalobill Jul 09 '20 at 03:37
  • @ybungalobill -- one more question: does your jurisdiction adopt the NEC straight-up, or do they amend it? (Some towns and cities have some rather...weird Code amendments, don't ask me why!) – ThreePhaseEel Jul 09 '20 at 03:51
  • @ThreePhaseEel: I think they follow NEC. The couple times I talked to the code officer here he seemed to be pretty lenient. – ybungalobill Jul 09 '20 at 04:10

1 Answers1

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It's pretty much all dependent on wattage

For the five kitchen appliances (and one lighting system) described in your post, the answer boils down entirely to wattage/amperage draw, as there are no specific requirements in the NEC for any of them to be on dedicated circuits; the fridge could be on a small appliance (kitchen countertop receptacle) branch circuit, and the remaining appliances can be on individual circuits or combined together as wattage permits; likewise, while the undercabinet lights can't be on a kitchen countertop circuit, they can go on any general lighting and appliance branch circuit that has the wattage to spare.

However, there are some constraints. Dishwashers, disposals, and microwaves all tend to be power-hungry beasts, meaning that you're going to have a hard time fitting even two of the three on the same branch circuit, and putting all three together on a single circuit is a non-starter. The fridge is the other constraint; if it's not on a kitchen countertop branch circuit, it must be on its own circuit, not a general lighting circuit. Given all this, I would look at pairing the dishwasher and disposal, if feasible, and also at putting the range hood and the undercabinet lights on the same circuit, given that you don't need a colossal commercial-style range hood to deal with domestic cooking needs, even if you have a jumbo range. (Commercial hoods are as beastly as they are because they have to keep air pollutants within OSHA limits throughout a restaurant cook's eight-hour shift despite near-continuous use of the appliance beneath them.) The microwave and fridge then wind up on their own circuits.

As to wiring methods, while there's nothing in Code that depends on that factor, the judicious use of individual THHN wires in ENT conduit ("smurf tube") can provide a major upgradeability benefit down the road. This is particularly handy in hard-to-upgrade spots, like when feeding the dishwasher and disposal, or for kitchen islands for that matter. You'll also have to make sure that you don't violate the 80% maximum total load rule for fixed cord-and-plug loads and the 50% maximum total load rule for fixed hardwired loads on convenience circuits (i.e. circuits that serve receptacles and/or lighting).

ThreePhaseEel
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