I have a shed that is wired via grey Schedule 40 PVC that runs underground
from a GFCI receptacle under my deck. The shed is up against a wooden
board-on-board fence similar to this:
I'd like to add a receptacle on a fence post about 15’ from the shed. Can I
come out of the shed with Schedule 40 conduit and run the conduit either on
top of or underneath the lower horizontal member of the board-on-board
fence? This would mean that the conduit would be between the vertical slats
of the fence for the full 15’.
If not, is burying the conduit and using a riser stub up my only other
Please explain the "expansion coupling" comment. I've used Schedule 40
under my deck, underground and up the side of the house before and never
dealt with expansion couplings.
Why are you suggesting them for this application? Not pushing back, just
trying to learn.
On Mon, 13 Jan 2014 15:56:03 +0000 (UTC), DerbyDad03
If you arrange the conduit so it can shrink and grow without being
trapped you can do without the fitting. RNC straps are designed to let
it slide and you want to strap the long section at a bend and allow
the intersecting part to be somewhat free (strapped ~3 feet away). If
you can't assure that, you do need the expansion fitting. The conduit
will buckle in the summer and pull apart in the winter.
To put this in perspective, PVC will expand close to a half inch
(0.406") in 10 feet over a 100 degree swing. That is not unusual
between a cold winter night and a sunny day in the summer. (ref table
This is interesting. I currently have 3 runs of grey schedule 40 conduit on
the back of my house. One runs vertically from the sill plate to the
soffit, 2 stories. One runs vertically from the sill plate to the roof line
of a one story addition. The third one runs horizontally from the sill
plate, under my deck, to a point about 15 feet from the house.
All three runs originate in conduit body fittings and terminate in fixture
boxes, either receptacles or lights. None have expansion fittings. As far
as I know, none have ever experienced bending or warping or any movement
that I know of. Granted, they are on the north side of my house and don't
ever get full sun. Temps range from below zero to mid-nineties at the
extremes, but not in short periods of time.
Have I just been lucky? Will the fact that you guys brought is up cause my
conduit to warp enough to come flying off the house the next the
On Tue, 14 Jan 2014 00:48:05 +0000 (UTC), DerbyDad03
If there is some wiggle room you usually get away with it but I bet if
you look in the summer, there is some sag taking up the slack..
I used EMT in my screen cage because I did not like the way PVC
What's a screen cage?
I painted both vertical runs to match my white house. The grey under the
deck is still grey.
One vertical run is for a receptacle box that used to power ice melt wires.
This'll be my second winter with a new roof, full soffit vents, ridge vents
and rafter bay baffles. No ice melt wires and no icicles last winter. If I
don't get icicles this year (or maybe next) I'll probably remove that run.
Then again, maybe not...as soon as I do, I'll probably get icicles.
*In addition to what Gfretwell said, it is also a code requirement. PVC has
expansion and contraction characteristics that can cause it to buckle and
warp. Your fence picture reminded me of a PVC conduit installation on a
fence in my area that I observe in passing every now and then. When it was
initially installed the pipe was of course nice and straight. Several years
later it looks like a derailed freight train. The total distance is perhaps
30' - 40'.
Yes, that's fine, as long as you're using conductors that are rated for the application. Non-
metallic sheathed cable ("Romex") is *not* permitted here: it cannot be used in wet
locations, and outdoors exposed to rain is a wet location *even inside conduit*. You need
to run UF cable or individual conductors of THHN, THWN, etc.
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