first time doing a more difficult outlet install (not just across a wall). Looking to install an outlet for a bidet in my 1st floor bathroom. I need to run a wire from the outlet above the sink to somewhere near the toilet. The ideal location would be on the wall behind the toilet right between the vanity and the toilet. The power for the sink outlet comes from above, so no wire in the crawlspace to use. Bathroom.

However, that wall is an exterior wall. I went into the crawlspace and did some measurements and it seems like the exterior wall is not really accessible from the crawlspace. The crawlspace opening happens to be right on the other side of the outlet wall. So I measured the distance from the crawlspace opening to the exterior wall, and then measured the distance from the crawlspace opening to the retaining wall. Based on that, seems like the exterior wall is about 3" deeper than the retaining wall. This diagram seems to be what I am seeing. I'm guestimating for the area right above the retaining wall as I can't really see it. Structure Diagram

There's a tiny 1.5" high 3" deep gap right above the retaining wall. I can't really see into it, but feels like there's wood at the end. But here's an attempt at taking a picture of it. enter image description here

So wanted to confirm:

  1. Does that diagram sound reasonable? And if so, then seems like using the exterior wall will be too difficult?

  2. How would you recommend running the wire from the outlet above the sink? I think I see several ways:

    1. Install the outlet on the side of the cabinet and run a wire through the cabinet
    2. Install the outlet on the side of the cabinet, run the wire down into the crawlspace, then back up into the wall that contains the outlet above the sink
    3. Open up lots of drywall and run the wire through all the wall studs
  • 3
    I'd come from the interior wall and put the outlet in the Vanity behind the toilet paper, avoiding the whole exterior wall access mess. I prefer to avoid fighting with building systems when there's an easier way available. Use conduit or MC-lite inside the cabinet to ward off "exposed to damage" concerns. GFCI is a given.
    – Ecnerwal
    Dec 10, 2021 at 13:42
  • 1
    If this circuit feeds more than 1 bathroom and your locality has adopted 2020 NEC 210.11(C) the new additional wording "countertop and similar work surface" added to the bathroom receptacle circuit requirements and the existing wording "shall have no other outlets" will require you to use a different circuit to feed the new receptacle. Dec 10, 2021 at 16:15
  • Definitely check the specs on the seat -- the heater/blower can draw a lot, and the manufacturer might demand a dedicated circuit. Dec 10, 2021 at 16:33
  • And... 2.4: landmarking on the toilet flange, bring conduit up from the crawlspace exactly behind the toilet and place a surface mounted gfci on the wall right behind the toilet. It's spectacularly un-pretty (albeit hidden), but also extremely easy. Dec 10, 2021 at 16:39
  • @Ecnerwal - But if OP comes off the load side of his existing outlet that's next to the sink - which I assume is GFCI protected - then he won't need another GFCI at the new outlet?
    – SteveSh
    Jan 9, 2022 at 13:13

2 Answers 2


To answer the question: Your diagram looks reasonable. It is probably possible to fish a cable from the existing socket into the crawl space. A professional with experience and the right tools might be able to do it with minimal wall damage. It may be necessary to remove the vanity, break a large hole in the wall beneath the existing socket to provide easier access to drill into the crawl space. You would not need to fully repair or paint the wall behind the vanity.

To address the actual need: Most bidets include water heaters that require a dedicated 20A circuit. You particularly should not put a bidet on a bathroom circuit that is likely to be used with a hair dryer. You need to run a new circuit from your breaker panel to the bidet location. Code may even require this (I don't know). The new circuit and for that matter the existing one should use GFI protection.


As noted in another answer, your bidet may need its own dedicated circuit. If that's the case, you're free to run the wiring through the crawlspace any way that's handy.

IF it doesn't and it can run on a 15A circuit, don't worry about the existing outlet, tap into the hot power that should be at your light switch. Take unswitched hot from the switch box, run it down the wall, through the crawl space and back up to the new outlet. Of course, if you want, you could tap into switched hot, then the bidet would only work when the lights are on. This would probably be OK, though not nice for a night time trip to the loo without turning the lights on - it may depend on where and how one expects to use this bathroom and whether working without the bidet would be acceptable in the middle on the night...

In order to know how to go about it, you'll have to consult your documentation.

  • This all assumes the receptacle is not on the same circuit as the switch, which isn't a requirement either way. And considering the absence of a GFCI we should assume anything is possible here. Mar 2, 2023 at 15:59

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