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Is This Outlet OK For Outdoor Use?

Posted by benesesso (My Page) on
Sun, Feb 24, 13 at 12:22

I'm in the process of adding a 20 amp. 120v line and outlet/receptacle to a steel gazebo I built in the yard. Went to Lowes and asked what would work, and the pics show what I bought.

Problem: The outlet doesn't quite fit the box. The small threaded holes at the ends of the mounting tabs interfere with the plastic ribs in the box.

I could just cut them off and use the much stronger larger holes which are meant to attach the cover. Then I thought about needing a GFCI or an AFCI receptacle. Seems to me the AFCI is the way to go. Would I need a special outlet, and will the box be OK? Thanks.


Follow-Up Postings:

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RE: Is This Outlet OK For Outdoor Use?

The regular 20 amp. outlet.


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RE: Is This Outlet OK For Outdoor Use?

First off, understand that 99% of the people at the Home Centers have no freaking clue about electoral requirements.

You need to have the receptacle protected by an GFCI (NOT an AFCI). That can be done by having a GFCI breaker or an upstream GFCI device (another receptacle typically) or by putting a GFCI receptacle at this location.

The receptacle doesn't really need to be rated for outdoor, but the box (which appears OK in your picture) and the cover (which needs to be fitted properly to the box and approved for wet locations. You also much use an "in-use" cover that allows the cord to be plugged in while maintaining the water resistant nature (these will be the larger covers not the little flippy doors.

I already see REAL PROBLEMS with your picture. That appears to be #12 NM coming out of the box there. That cable is ******NOT***** approved for wet locations. Underground (in conduit or NOT) is a wet location. You must use wet rated conductors (THWN for example). Further, you should not be running NM inside conduit other than for short runs for protection from damage.


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RE: Is This Outlet OK For Outdoor Use?

Thanks for the reply--and the bad news. I wasn't aware that NM isn't allowed underground even inside conduit. I did notice the grey conduit says "For above-ground use". Do they make a different conduit for burial?

Here in the Phoenix area our outside problems are UV, not water so much. The intense summer UV just tears PVC to shreds.

OK, I have an idea. I haven't backfilled the 30' conduit trench yet, so what if I get some "direct burial" (UM?) 12 gage wire and forget the conduit?


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RE: Is This Outlet OK For Outdoor Use?

"For above-ground use" manes the conduit is UV stable.

The unmarked conduit is rated only for burial.

If you have a conduit system just purchase individual wires with the correct rating (like THWN).

If the conduit is only to protect the a cable as it exits the ground, you could use type UF cable.
You will need a cable clamp at the UF entering the conduit.


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RE: Is This Outlet OK For Outdoor Use?

Arrgh! The conduit has too many bends to pull something else thru it, even if I use the NM to pull it. So what is better for direct burial, UF, UM, or THWN?

Where does a cable clamp go? In the dirt (rust?) or just above the ground?

I'd go pound on my "technical advisor" who said NM inside conduit was OK for burial, but he's bigger than me.


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RE: Is This Outlet OK For Outdoor Use?

Did some checking on the 'net and found unpleasant things like buried conduit must be at least 18" deep and direct burial 24" min.

There is no way that's going to happen here. The trench is only 6 to 8" deep and I ain't digging any deeper.

I'm thinking of leaving the NM inside the conduit but not hooking it up, and run some direct burial wires instead-once I figure out what to buy.

Um, how low would AC voltage need to be to avoid code compliance? I know sprinkler stuff is 24v, but I think that's the limit to avoid heart seizure possibilities with AC. Wish I could go to 60 volts because I have few big 2-1 transformers, but I think 60 volts AC can kill.


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RE: Is This Outlet OK For Outdoor Use?

3 single strands of # 12 is a lot less in diameter than the NM you have in there now!
Pull out the NM, and pull in 3-#12 THWN

How may bends are do you have in the conduit?
Code allows for only 360 degrees of bends between pull box and /or j-box.
As for burial-To be code compliant,
if in PVC, you must be 18" deep-PERIOD.
If using direct burial cable-24' deep-PERIOD


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RE: Is This Outlet OK For Outdoor Use?

Thanks. Leaving the house there's one 90 and one 45 elbow, then ~30' of 3/4" conduit. But inside the conduit I also have some 3/8" OD round 16 or 18 ga. wire for my 24v sprinkler valve next to the steel gazebo.

I suppose that violates another part of the code--induction by the 120v (actually usually measures ~125 v) into the 24v wire?

Guess the Rain Man sprinkler valve won't like that. Will measure the voltage after I'm done and use a light bulb as a resistor if I have to reduce the voltage.

If I sell this house I'll cut the wire off and remove the box. The new owner can hire someone if he wants power out there.


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RE: Is This Outlet OK For Outdoor Use?

"As for burial-To be code compliant,
if in PVC, you must be 18" deep-PERIOD.
If using direct burial cable-24' deep-PERIOD"

Actually, Residential branch circuits with GFCI protection on 20a circuit or less can be buried at 12". The all caps "PERIOD" is not necessary.


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RE: Is This Outlet OK For Outdoor Use?

But 6" isn't an appropriate depth for either direct bury or plastic conduit. You can get by there only with IMC or Rigid or by using a 2" concrete cover.

The low voltage stuff shouldn't be an issue as long as you keep it out of spaces where the higher voltage stuff connections are made.


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RE: Is This Outlet OK For Outdoor Use?

Great replies. Bought some 12 ga. UF-B (what's the B for?). Going to remove all the conduit and go direct burial. Will not run the 24v wiring from the house--will use an outdoor transformer in the gazebo, fed from the new UF-B.

Also bought a 20 amp. GFCI receptacle and the big "in use" box cover.


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RE: Is This Outlet OK For Outdoor Use?

I routinely use rigid conduit instead of having to rent a 'ditch witch' and go deeper than 6 inches of cover.

A single good shovel bite, turn it over onto a piece of tarp along the path, lay conduit, use the plugs held together by the grass to 'fill' the trench.

Minimal landscape damage.

Just tell the owner to water and flatten the earth wen damp along the 'trench' and it is invisible in a few weeks.

It beats tearing up a front yard to run a newline to a lamp post.


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RE: Is This Outlet OK For Outdoor Use?

"A single good shovel bite, turn it over onto a piece of tarp along the path, lay conduit,"

Brick's never seen Caliche I'll bet.

Here is a link that might be useful: Caliche


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RE: Is This Outlet OK For Outdoor Use?

So the grey PVC conduit isn't rigid? Is the rigid stuff galvanized steel?


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RE: Is This Outlet OK For Outdoor Use?

Nope, only metal (or concrete) is allowed at your depth .

Here is a link that might be useful: Rigid & Intermediate Metallic Conduit

This post was edited by saltcedar on Wed, Feb 27, 13 at 13:17


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RE: Is This Outlet OK For Outdoor Use?

As salty says it is "rigid and intermediate" metal conduit that can be placed at only 6". I didn't spell out rigid metal because we don't use "rigid" to refer to plastic no matter how inflexible it is.

Unless Brick's got a much bigger shovel than I do, He's not getting a trench big enough for a conduit plus 6" of cover with one bite.


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RE: Is This Outlet OK For Outdoor Use?

My shovel is likely the same size as yours.

Drive an 8 inch shovel into the ground till the top is flush (wetting the soil helps), move to the other wide and repeat.

Out comes a plug more than adequate for 6 inches of cover.

Repeat.

There are also rocks in the soil in most places.

You just make more 'plugs' to get around them and pull them.

It still saves damage over a ditch witch.

you can also use a 'drain spade' that is narrower but well ever a foot long.

This post was edited by brickeyee on Wed, Feb 27, 13 at 16:40


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RE: Is This Outlet OK For Outdoor Use?

Yes Brick there are rocks almost everywhere. I grew up around glacial till soils in Ohio. Big difference between that and soils that are essentially
poorly formed concrete.

Here is a link that might be useful: Good luck with your shovel in this!


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