Ideally, I would like to place an outdoor power outlet box right over this 1/2" PVC conduit leading to it so there is A) no conduit visible around the box and B) there isn't an extra 90° bend to make driving wire harder. Is there a box that I can have a hole in the middle of that this pipe (of course trimmed accordingly) will fit over to accommodate the aforementioned minimalist design?

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    Whatever box you use, it will have to be attached to the building in some way. According to NEC 314.23(F) the box cannot be supported by a single conduit. – Tester101 Nov 20 '15 at 21:36
  • National Electrical Code 2014 314.23 (F) Raceway Supported Enclosures, with Devices, Luminaires, or Lampholders. An enclosure that contains a device(s), other than splicing devices, or supports a luminaire( s), lampholder, or other equipment and is supported by entering raceways shall not exceed 1650 cm3 (100 in.3) in size. It shall have threaded entries or identified hubs. It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 450 mm (18 in.) of the enclosure. – Tester101 Nov 20 '15 at 21:36
  • Attaching it via screws with concrete anchors is not the problem here – amphibient Nov 20 '15 at 21:53

That is where we normally put them and nothing in NEC forbids it.

Also note that a lot of outdoor boxes will have a hole right in the back middle to support this.

After very gently inserting your pipe through the tight hole in the back of your box, please release a generous amount of caulk around the pipe to keep the water out.

(Also box must be screwed/secured into wall)


If you want to set it in the wall.

If you want to lay it flat on the wall.

  • Most outdoor boxes will have a 1/2" threaded hole in the back. He will need to drill this out. – ArchonOSX Nov 20 '15 at 20:39
  • The new plastic ones I buy either have a punch out or something that you have to drill out. I don't install metal boxes outdoor for a variety of reasons. – DMoore Nov 20 '15 at 20:43
  • Hmm good point. – ArchonOSX Nov 20 '15 at 20:45
  • See my comment to A.I.'s answer – amphibient Nov 20 '15 at 20:51
  • @amphibient - updated for your pleasure. – DMoore Nov 20 '15 at 20:56

first of all you NEED to chisel out around the pipe an area big enough to glue either a male connector (t/a) or a coupling onto the pipe. period. that is, if you want to be up to code. if you don't you can do as suggested above. with a coupling (not recommended), you will have to find a 1/2" Box Adapter, that will glue into the coupling. to be very watertight, you glue the crap out of the back of it that contacts (and glues to) the back of the box. any weatherproof pvc box will do, use a 7/8" unibit or a hole saw for a 1/2" fitting. (7/8"). i wouldn't recommend this way because you would have to chisel a hole twice as deep into the cement for this coupling to be flush with the wall, than you would for a connector. with the connector the threads have to stick out from the wall so you can screw a metal box onto them.

the better way would be the connector (male t/a). you will have to, in either case, chisel the cement out about an inch back into the wall. you cut off the pipe as close to flush as you can, better if you have a dremmel tool and can cut it about 1/8" inside the wall with a cut off attachment. but even if you can only cut it flush, say with a sawzall, you can still get away with it being an 1/8 or so off the wall as long as you screw it into the cement on two corners (hammer drill will help, but for two one inch deep holes for plastic anchors, you could prolly use a regular drill with masonry bit).

glue the connector on. buy a 1/2" sealing locknut if you are using a plastic box and use it on the inside of the plastic box. if a metal box with a threaded hole, just put any kind of goop on the threads and screw the box on until it's tight and vertical or horizontal. then use plastic anchors to attach the box, add your gfi protected device and a bubble cover approved for extra hard use, and your done. just to clarify: if you use a plastic box, the 'box adapter' and coupling will work OR the male t/a. if you use a metal box you HAVE to use the male t/a only. and i think i said to use the connector and the metal box. that's what i would do. peace out and don't forget to wear eye protection when you are chiseling, ya chizzler!


Ask at the hardware store for a Weatherproof Outdoor PVC Round Junction Box. Both the metal and PVC outdoor boxes have a hole at the back, but the metal ones are usually threaded. One product that looks like it will work is the Carlon PVC Round Outdoor Junction Box (E365DR) which is probably stocked in any electrical dept.

  • The problem I'm having is how to adapt the PVC pipe to a th threaded ending every one such box is designed to expect at it's knockouts. If I could find a box that doesn't have threaded knockouts but just PVC straight females, it would solve my problem – amphibient Nov 20 '15 at 20:39
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    A round box is not what is needed here. A device box is. – Speedy Petey Nov 21 '15 at 1:39
  • @amphibient Don't secure the PVC too tightly to the box. It expands and contracts so much with temperature changes that it will break. For example, if you glued a box tight against the wall onto that conduit during warm weather, then experience very cold weather, contraction of the conduit can litereally break it. – Craig Feb 21 '16 at 21:45

Find a box with a smooth back and use a hole saw To drill out for the size conduit you have. Electrical hole saws are sized for the trade size of the pipe so ½" conduit is ⅞" and ¾" conduit is 1 ⅛". Make sure you caulk behind the box and around it to seal it from moisture.


Cut the conduit off flush and insert a chase nipple in the hub in the back of a box. This might be easier.

  • I think that will make it leak water plus won't be firmly attached – amphibient Nov 20 '15 at 20:50
  • If you attach PVC too tightly without some kind of expansion coupling, it will break from thermal expansion and contraction. Better in this case to secure the box to the wall, trim the conduit back a bit and caulk generously around the conduit so things can move a little. – Craig Feb 21 '16 at 21:43

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