I recently had to install an outdoor electrical recepticle for a fountain.
This new recepticle was wired in series from an outlet in my backyard,
using 12-2 outdoor wiring. My question is, do I need to use conduit
underground, or can I just bury the wire 12" deep? I've heard conflicting
stories on this. Someone told me that an electrician told them anything
underground had to have conduit around it in case a shovel or something
else were to hit the wires. However, I've also heard that conduit can
cause the wires to overheat and that it defeats the whole purpose of having
outdoor wire in the first place. Which is correct? I haven't been able to
find the electrical codes for WA online, which is why I am asking here.
Also, do I need a GFCI on an outdoor outlet? Someone told me it is a bad
idea to use a GFCI for a fountain or anything with a motor because
fluctuations of the motor can cause the circuit to trip. This made sense,
but if a GFCI is required outside, how else are you going to get power to a
Any help would be greatly appreciated. Thank you.
You're going to have to ask your local inspection/permitting office. Burial
requirements vary quite a bit from place to place. Here, with NMW (aka UF),
you must bury it 24" or more. With "protection" (a board or PVC pipe, but
that doesn't work in the US), we can get it to 18". Shallower than that,
it needs steel conduict.
Motors will _not_ be an issue with a GFCI. Especially a small one
like you're likely to be using. The only time where you avoid GFCIs is
things like fridges or freezers because of the consequences of a failure -
and the NEC specifically permits you to _not_ use GFCIs for that.
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
If the wires are protected by a GFCI back at the house, you should be
able to use direct burial only 12" deep. (Table 300-5, column 4,
"Residential Branch Circuits Rated 120V or Less with GFCI Protection and
Maximum Overcurrent Protection of 20 Amperes")
If the wires are not GFCI protected (like if you had a GFCI outlet at
the fountain but no GFCI protection at the house) you would have to bury
the cable 24" deep.
From experience, even plastic conduit is a cheap solution.
Chipmunks and ground hogs create expensive repairs once they
gnaw into the wire (which causes GFCI trips). Also a good
idea is to position or slope conduit so that it neither
collects nor holds water.
Big Daddy wrote:
You can direct bury, but conduit is cheap enough to get some extra
> However, I've also heard that conduit can
This is why the high tension power lines are run for miles overhead instead
of under ground. If the fountain pump going to pull maximum load of about
15A on the 20A circuit? No, then you will have no problem. Right in thory,
wrong in practical terms.
Yes, but only one per circuit. If the present setup has GFCI you are OK.
You do not want them in series.
Again, in the right circumstances it may. My fountain has been running four
summer with no problem.
Outdoor outlets need outdoor receptacle covers. The old type has
individual hatches that seal up the openings like submarine hatches.
There is a newer type which is a clear plastic projection over the
outlet. It has room for and completely covers the plug, further
protecting the outlet and the plug cord from the elements.
Your junction box should probably be plastic which will be safer and
minimize corrosion problems. Be sure to wire the ground wire to your
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