I am planning to run a new electrical wiring in my backyard and start from where the current outlet is at the wall (behind my kitchen):

enter image description here

It's right above the deck and here is the picture under the deck (about 4 feet tall)

enter image description here

I plan to run the wires under the deck using all PVC conduits. However, I am wondering how to connect the new wire from the wall.

I am thinking of two options.

Option 1:

Pull the wire through the bottom of existing box and box cover like this

enter image description here


However, the current electrical box/cover is very flat to the wall. I don't know how to pull the wire through the bottom like the picture.

Option 2:

This leads me to option 2 which is to run the wire inside the wall first, and then pull it outside the wall through a LB box under the deck:

enter image description here


But to be honest, this option is too complicated with many small parts: nut connector, EMT, conduit connectors, LB, RMC, 4x4 box, seal ...

I am leaning toward the first option (Option 1). What are the pros and cons? If I go with Option 1, I have to drill a hole in the deck (which is fine) to run under it. But how do I "protrude" the box at first? Do I replace the existing box so it's staying outside the wall?


I added the extension box and ran the PVC through the deck outside.

enter image description here


  1. I will add a strap at (A). Right?

  2. Do I need to put glue or seal around the hole at (B)?

  • Instead of updating this question, you should ask a separate question. Add a link in the new question, that points back to this one, so folks can get the backstory if they want. Also include a photo from below the deck (if possible), since the strap may be able to be placed there instead.
    – Tester101
    Commented Jul 1, 2016 at 12:44
  • 1
    The support that is required by code in this situation would normally be a pipe hanger (Minneralac or "Minnie") attached to the siding at point (A). Unfortunately, this would require removing the pipe. Manufacturers also make a one hole strap with a back strap that can be attached after the conduit is installed since the attachment screw hole would be off to the side of the conduit. Both of these supports are designed to support the conduit at the standard distance away from the wall where most boxes have their conduit entries placed. You don't need caulk at point (B) unless you want to.
    – ArchonOSX
    Commented Jul 2, 2016 at 0:59
  • Do you mean something like this aimedia.co/media/images/NM2000-2.jpg ?
    – HP.
    Commented Jul 2, 2016 at 7:44

2 Answers 2


I would suggest the use of a weatherproof (WR) box extender. One of which could be installed over the existing box giving you sides on to which to connect the PVC conduit.

The following is an example. No endorsement of specific products is implied.

enter image description here

  • I like your solution the best and ran to the store to buy the part. I updated my photo with few more questions if you don't mind.
    – HP.
    Commented Jul 1, 2016 at 4:35

Edit- based on revised question:

A) You do need to support th conduit within 3 ft of the box, but the hole in the floor looks to be within 3 ft.

B) You can yoke two strut straps together where they go through the floor. You can also put caulk in the hole if you wish, but that has nothing to do with proper support... and since it is a hole on a deck, caulk doesn't sound useful.

enter image description here

  • Thanks. My goal is to just run the wire to under the deck and the new outlet will be far away (in middle of backyard).
    – HP.
    Commented Jun 30, 2016 at 22:14
  • 1
    @HP. oh, thanks for explaining. I see that you added a couple questions. I revised my answer entirely. Commented Jul 1, 2016 at 12:25

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