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My question is very similar to the one asked here, but I have some additional specific questions about how to do this in a code compliant way.

Here is a diagram of my proposed wiring wiring diagram of proposed garage circuit to split duplex receptacle outlet

The receptacle outlet outlined in blue at the far right of the diagram is the one in question. This is a weather resistant receptacle outlet on the outside of my garage. I'd like one of the receptacles to be a constant supply for an outdoor security camera, and the other to be switched for string lights or something, and have them come on/off with the same switch as the existing carriage lights. The 15A circuit for the lights already exists, it'd just be a matter of splicing some more 14/2 off of the light fixture and bringing it down to one half of the receptacle outlet.

My questions are as follows:

  1. Will this be code-compliant as is or are there any additional things to consider?
  2. Can both circuits be fed by 1 double-pole breaker? If so, what amperage should that breaker be? Is there any particular advantage or disadvantage to this compared to my current proposed solution of tying two different capacity breakers together via something like this?
  3. Can the WR receptacle outlet be 20A instead of 15A?
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    Why not just add another duplex outlet next to the existing one so one duplex outlet is switched and the other one isn't. then you don't have to tie the breakers and you have extra outlets.
    – JACK
    Commented Mar 8, 2022 at 21:58
  • You'd have to handle-tie a 15 and 20 to meet the common shutoff requirement, and the fact that you show 14Ga wire so that can only be 15A. Or reduce the formerly 20A circuit to 15A and use a 15A double-pole. This appears to be overcomplicating the situation for no particularly good reason.
    – Ecnerwal
    Commented Mar 8, 2022 at 22:04
  • Thanks for all the suggestions, I didn't realize I needed GFI protected receptacles. The electrician who wired my garage only 2 weeks ago didn't install them, and I don't think the breakers are GFI protected either. My main goal here was to come up with a way to accomplish this without running a ton more romex, but seems it's better just to do it as 2 separate GFCI receptacles on 2 separate circuits, a switched 15A and constant 20A. The new string of 20A outlets in my diagram can then be tied in series off the outdoor GFCI receptacle, making them GFI protected as well, correct? Commented Mar 8, 2022 at 22:35
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    If you want a new string of outlets including the outdoor one to all be GFI protected, you only need one GFI outlet, at the location where the feed to them all is provided. You also need some stickers so people know what's going on. I'd make the outdoor one last, and put the GFI inside.
    – jay613
    Commented Mar 8, 2022 at 22:40
  • Receptacles INSIDE the garage also need (code required, not prefrence-based) GFCI protection. Which can just the be first receptacle, properly wired as line in from breaker and load out to other receptacles (with required stickers); or a GFCI breaker. If your electrician did not address that, you need to have a talk with them.
    – Ecnerwal
    Commented Mar 8, 2022 at 22:44

3 Answers 3

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Rather than make life difficult by conjoining two circuits on one outlet, simply make it be on one circuit, half-switched. The security camera power supply you want the unswitched half for is hardly likely to overload the lighting circuit.

enter image description here See, that wasn't so difficult, and now the circuits are not commingled in complicated ways. If there's 12/2 to the receptacle already you can use that on the 15A circuit without replacing it. If doing it new you could use 14/3 with ground or 2X 14/2 with ground (which oddly is often cheaper than 14/3 - due to sales volume, I suppose.)

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  • This makes sense, thanks. For context, there is no 12/2 to the receptacle yet, it's currently tied into the existing 15A circuit for the lights, so the whole thing is switched. The receptacle is about 5ft below the light fixture where that circuit ends, and I was hoping to run as little new romex as possible, which was why I drew it up this way. I had planned to run the new 12 gauge over there anyway for the new 20A outlets, which is why I figured I could just supply power to the existing receptacle with that. Commented Mar 8, 2022 at 22:24
  • Easier still, just run 14/3 from switch to lamps to outlet. White is neutral, black is always-hot, red is switched-hot. You will need to use a 2-gang box with a GFCI and a switch, or a GFCI+outlet+switch combo device. So that you can GFCI-protect the entire circuit, lamps included. Commented Mar 9, 2022 at 2:50
  • I believe we have 14/2 in place, and I have certainly seen cases where the one extra wire in 14/3 more than doubled the price, not that it should.
    – Ecnerwal
    Commented Mar 9, 2022 at 3:29
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You say this is for an outdoor outlet. It needs to be GFI protected. There's no GFI outlet that can be split that way. You need to install two of them in a two-gang box. "Wet in use" for your camera. You don't need to tie the breaker handles but it wouldn't hurt, to ensure anyone working in that box isn't surprised by a live circuit. You could possibly do it your way, with a split receptacle, by putting in GFI breakers but you probably don't want all the other sockets and lights protected that way.

Also, as long as you're running in-wall cable and installing outlets for two fairly permanent devices, do consider making this two separate single-gang boxes, each located as near as possible to where they string light and camera will respectively be plugged in. That way you don't have power cords dangling around outdoors any more than necessary.

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  • Ok, thanks, the electrician who wired my garage (only 2 weeks ago) didn't use GFI outlets, so I thought I didn't need them. I think installing a 2-gang box and cover in addition to just running a new constant 20A supply would be a good solution here. Commented Mar 8, 2022 at 22:27
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Run 14/3 from switch to lamps to outlet.

Now you have 3 wires:

  • Black is always-hot (for unswitched receptacle)
  • Red is switched-hot (for lamps and switched receptacle)
  • White is neutral (for everything that is not a switch).

That's the easy way to do it.

You will need GFCI protection for all garage and outdoor receptacles. You can't split a GFCI receptacle, so that won't be an option. You will need to use a GFCI device "upstream" (closer to the panel) that protects the switch and everything downline from it. That could take the form of a GFCI breaker, a GFCI "deadfront" or receptacle before the switch, or a combo GFCI+receptacle+switch device at the switch. You don't need the receptacle in the combo, but that's the only way to get both unswitched and switched from a GFCI device. (a pure GFCI switch won't provide an unswitched tap, since the GFCI is the switch).

Will this be code-compliant as is or are there any additional things to consider?

Well, your plan can work if you provide for GFCI protection for everything. Even if you use 2 circuits and split the receptacle as you plan, you still need GFCI protection somewhere before the switched side of the outlet.

Can both circuits be fed by 1 double-pole breaker? If so, what amperage should that breaker be?

No, because they need to be different amperages. Code requires that the garage have a 20A circuit. Even if your installation pre-dates that Code requirement, you can't downgrade. And you have a 15A circuit for the lighting. You would have to rewire the lighting circuit with #12 wire and make it a 20A circuit (not allowed in Canada).

It also wouldn't save you any wire since you can't share neutral downline of a GFCI protection device.

Can the WR receptacle outlet be 20A instead of 15A?

You can't put a 20A receptacle on a 15A circuit, so no. You would need to wire the lighting circuit in #12 and make it a 20A breaker.

my current proposed solution of tying two different capacity breakers together via something like this?

That only works if your breaker is Square D QO type. You can't mix-n-match breakers and panels.

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