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Working in a 1960's house and trying to go through and see what breakers go to what, so I can write everything down, just to have knowledge.

I have one 20 amp circuit (for kitchen and dining room) with a 12/2 wire going first to a single 15 amp small round floor outlet (not a duplex), then it goes to two 20 amp duplex wall outlets, then over and up to two 20 amp kitchen wall outlets and finally a 15 amp outlet on dining room wall. Will this work OK, with the first outlet being a single 15 amp, since I read you can't have a single 15 amp outlet on 20 amp circuit, or does that mean you just can't have a 15 amp outlet without other outlets on that circuit?

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2 Answers 2

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It means that on a 20A circuit, if the only outlets are 15A, then there must be more than one of them. You're fine with respect to that rule. This means:

  • 1 - 15A - no good
  • 2 - 15A - duplex or two singles - OK
  • 1 - 20A - OK
  • 1 - 15A plus 1 - 20A - OK

And any higher number (15A and/or 20A) is OK.

There are two fairly common modern code compliant situations where a single 15A receptacle will be used as part of a 20A kitchen circuit:

  • Clock - A single receptacle placed on the wall, often recessed, for a clock. Not as common these days as (a) even those of us who never wore a watch commonly walk around with a portable computer that happens to include a clock function, (b) most conventional ovens/stoves and microwave ovens have clocks and (c) many people have a clock radio (or other audio/visual device that includes a clock) in their kitchen.
  • Gas Cooktop - You can install a receptacle for the ignition circuit of a gas cooktop below the cooktop but as part of one of the countertop receptacle circuits.

There are two other things to consider in your situation:

  • GFCI - If you do not already have GFCI protection for the kitchen receptacles, that is highly recommended. You can do that at the breaker - protects everything, whether you like it or not, at the first kitchen receptacle with load wired correctly protecting everything following it in the circuit, or at each kitchen receptacle with load wired correctly (in this case, wires pigtailed to line instead of load) to protect only the kitchen receptacles. This is an important safety upgrade that is worthwhile in every kitchen.

  • Current code limits what places the kitchen receptacle circuits can serve. You may or may not be in violation of that rule, as it is complicated and, I believe, includes at least some non-kitchen locations. You are grandfathered in on this rule, but if you add any new kitchen receptacle circuits (often a very useful upgrade), they should be dedicated to the kitchen.

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    You probably want to exempt the outlet that powers the fridge from GFCI protection, as allowed by code Commented Jan 30, 2022 at 17:18
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    Thank you for clearing that up. That single outlet in the floor was throwing me off. I appreciate the help. I'm replacing the old outlets with GFCI units, already. Thank you, again!
    – Brad
    Commented Jan 30, 2022 at 17:26
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    @Brad if you spend 20 minutes learning how GFCI downline protection works, then you can protect the entire downline circuit from one GFCI device, for significant cost savings - at the cost of being required to label them "GFCI Protected" (NEC 110.3 / instructions 8c). If you prefer each GFCI receptacle protect only itself, that's fine but do not use Load screws (they are for that other thing). The instructions say how to put 2 wires on each Line screw. Chaining multiple GFCIs line-load-line-load etc. creates a big mess when a ground fault happens, you'll never get them all reset LOL. Commented Jan 30, 2022 at 20:24
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    Losing the clock is a mistake. The analog clock goes on the same circuit as the fridge and tells you how long the fridge has been without power.
    – Joshua
    Commented Jan 31, 2022 at 15:47
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    @Joshua Useful, sure, but a fridge thermometer with a max temp recording feature is better. Time without power is less important than if the fridge went over 40°F.
    – Bloodgain
    Commented Jan 31, 2022 at 22:03
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What trips most people up here is this: how many receptacles does this device count as?

NEMA 5-15R duplex

That's a NEMA 5-15R duplex receptacle (which is ubiquitous in the US). It's a 15A plug but it has two receptacles. It is also rated for 20A pass-through (meaning you can use it inside a 20A circuit). When they mean one receptacle, they mean these uncommon receptacles

NEMA 5-15R single

You can't put this one on a 20A circuit by itself. The reason is that the receptacle would not be properly protected by a device pulling more than 15A. A single duplex receptacle is perfectly fine because you can plug multiple devices up.

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    I kind of understand what this rule intends, but in absolute protection there is no difference between a single outlet with one device plugged in and a double outlet with one device plugged in. Only when there is a continuous 5A load on the 'other' outlets is the 15A socket properly protected.
    – Pelle
    Commented Jan 31, 2022 at 14:41
  • @Pelle I think the difference is that one will overload while the other only might overload
    – Machavity
    Commented Jan 31, 2022 at 21:40
  • the point I'm trying to make is that the second will overload just as much, unless there is a pretty significant load on the other outlets, which is by no means guaranteed and even less enforced. Personally I'd sleep much better when all outlets are protected to their maximum rating.
    – Pelle
    Commented Feb 1, 2022 at 18:14

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