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I would like to add an outdoor receptacle directly to my outdoor breaker panel for some simple string lights. The idea would be to install new breaker, run flexible conduit from knockout on bottom of panel up to just beside the panel and into an outdoor rated single gang box and outlet cover. The conduit run would likely be less than 3 feet.

Can I use 1/2" or 3/"4 flexible PVC conduit and will I need THHN or THWN rated 12 gauge wire, black/white/ground? 15 amp breaker and 15 amp GFCI outlet?

I have 12/2 cable but understand I can't run it through the conduit. I'm in Colorado if local codes differ greatly.

Open to suggestions!

Breaker Panel

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  • When you say "flexible PVC conduit" are you referring to "Carflex" (LFNC, liquidtight PVC, usually grey) or "smurf tube" (ENT, that bendy blue stuff)?
    – ThreePhaseEel
    May 23, 2020 at 3:31

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Sure. What you're talking about is similar to the "Electrician's Outlet"... an outlet right next to the panel which is fed by a dedicated breaker. So the electrician can plug in portable lights etc. when the rest of the house is turned off for maintenance. That's pretty much standard practice for interior panels.

The electrician's outlet just uses a conduit "nipple" (prefab short pipe) that gives you an inch or so of length, so you get far enough away from the panel so the covers don't jam.

One common trick I see is using an offset nipple, which is about 2" long and has a small zig-zag. The offset isn't used for anything, it's just a handy, pre-made 2" nipple lol.

But if you want to run conduit a little farther and make it 3' away, that is fine. I recommend planning on water getting into the pipe, and exiting the bottom of the panel in a "drip loop" sort of deal.

Any outdoor recep is going to need an outdoor in-use cover.

You cannot use Romex (actually NM-B) in conduit because Romex (NM-B) is not rated for outdoor use. Also, there's a size issue: you must treat any cable as a single round wire of the large diameter (because it twists), and that makes it too big for many conduits. UF cable is allowed outdoors, but it's even thinner and wider than NM-B, and that makes it require HUGE conduit!

I'm not really sure what people's hangups are with THHN, it's really, really wonderful stuff, especially stranded. You'll never want to alligator-wrestle Romex again! The only snag with stranded is it's hard to hook over screws, but GFCI receps have screw-to-clamp terminals, and that makes it easy.

If you run #12 wire you are welcome to use either a 15A or 20A breaker as long as it's a dual 15A recep. (a 20A recep is also acceptable on a 20A breaker).

All the THHN I own is 12 AWG (except for the larger stuff obviously). I don't see any reason to own it any #14. #12 works for #14 and now I only have to stock one thing.

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  • This Romex/Southwire cable can be used outdoors. Can we stop using "Romex" as a product type? It's both ambiguous and confusing.
    – isherwood
    May 22, 2020 at 18:13
  • Thanks! Just for clarification, the only knockouts are on the bottom so if I want to use a 2" offset nipple and mount it to the side I'll just need to drill a 1/2 hole on the side where I want the outlet to be, correct?
    – Blaine
    May 22, 2020 at 18:23
  • @Blaine Well check the instructions to see if it forbids side entrance (that might void its outdoor/wet location certification). But if it says "go ahead" then go ahead. Otherwise you may be better off with the flex, just to try to keep water out.
    – Harper - Reinstate Monica
    May 22, 2020 at 18:27
  • 1/2” conduit is a 7/8 hole saw, I have not seen a modern panel that ever would be delisted from 3r a Myers hub worst case or lock nuts with seals will even work on the top, but as I mentioned even listed components can and do leak that’s why I prefer side. But the same seals are required in any orientation.
    – Ed Beal
    May 22, 2020 at 18:54
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    In addition to Installation Instructions of the cabinet (for UL compliance) at least NEC section 312.2 says penetrations "above the level of uninsulated live parts shall use fittings listed for wet location". So you would need to be down low because a hub would require a larger offset than a nipple. A 90° connector near the bottom of the cabinet and mild LNFC (sealtight) offset to the bottom of a bell box might provide a tidy appearance.
    – NoSparksPlease
    May 22, 2020 at 19:12
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You can use a short nipple and mount the box (a water resistant or Bell box) right next to, over or under the panel , flex is expensive. I like going to the side because then the box and panel vertical surfaces don’t leak. You cannot use Romex because it is not rated for use outside. 1/2 “ nipple and thhn/thwn will be good in 12awg or 14 awg. 12 for 20 or 15 amp. 14 awg for 15 amp. You will need a GFCI breaker or WR rated GFCI receptacle (I suggest a WR rated GFCI receptacle as the electronics are coated and will last longer than a GFCI breaker In this location. The in use or extreme duty cover finishes it up.

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