ECN Forum Forums General Topics of the Trade General Discussion Area cable bury depth

Hi all, I am a first time poster to this forum. My question is about the burial depth of 12/2 w/GND cabling that I will be running out to my garden area for a duplex. Also, will conduit be needed where the cabling comes up out of the ground? Are these subject to local codes? If so, I am in GR Michigan.
Thanks in Advance,
Dave

>My question is about the burial depth of 12-2 w/GND cable
Sounds like it will be UF cable hauling 120 V.
18" inches should work.
You also have options of running rigid conduit or pouring concrete over it.

> will conduit be needed where the cabling comes up...?
Yes. Dare I ask what this is running to in your garden?

>Are these subject to local codes?
Yes, if any.

Please protect the circuit with a GFCI before it leaves your house.

>Dare I ask what this is running to in your garden?
Well, I had "build a pond" on my "honey do" list, so now I must provide power out to it for the pump.
Thanks for the quick response!
Dave

>for the pump.
Your pump should work okay with GFCI.

In case it ever develops a crack, the GFCI can protect anyone who might be wading in the pool or stepping on the pump at the time.

Will the pump be hard-wired or plugged in?
You must use connections, boxes, and covers that are suitable for a wet area while in use. Otherwise, the GFCI will trip when they get wet.

xformer,

Welcome to the Forum.
If you do as DS says and protect your UF cable with a GFCI before going underground you can save yourself a little digging. You'll only need 12 inches of cover by code.

Bill

I'm sorry if I am not properly responding to this topic but a closer look into the code is in order here. As my company wires over 250 swimming pools a year in a multi-jurisdictional tri-state area a better understanding of direct burial is in order here. NEC 300-5 states that direct buriel i.e. UF cable must be 24" covered not 18". If THHN in PVC conduit is used 18" is permitted. Concrete encasement does diminish this by 6" either way. The exception is only if the circuit is GFCI protected from the panel and not at the pump. The easiest method is to use #12 THNN in IMC or RIDGID conduit where 6" buriel is all that is needed. A foutain pump on 120 requires GFI protection on residential use. If the pump is 240 hard wire it requires no GFI protection on residential usage.

dbc,

Welcome!

Look at column 4 in table 300-5 ('99 NEC)
As per 300-5 in Residential applications 120 volts or less and 20 amp circuit maximum if it is GFCI protected a cover of 12 inches minimum is all that is called for.


Bill

[This message has been edited by Bill Addiss (edited 07-07-2001).]

welcome new posters !

my 2 cnts;

I'm getting a bumper sticker;
'just say no to direct burial'

also, make it THWN for the location

picky, picky, picky...

Well, I really started something with this topic, eh? So, now what should I do? I am thoroughly confused. I already have the UF-B 12/2 W/GND cabling and a wet location 2x4 duplex box and was planning on pulling power out of the nearby shed. How about I put GFCI in the shed where I will get my power, then bury the cable 24" and use rigid conduit where cabling enters and leaves the ground? does this sound like an adequate install? By the way, I am really grateful for all of the help on this matter, Thanks to all who have taken the time to read and respond this posting!
Dave

xformer,

It's not a problem. The Book is clear on it.
120v circuit GFCI protected before it goes underground, circuit is 20A or less and it is a Residence. 12 inches is what it says. We do it all the time.

Note: the info above is right out of the Code book, your local inspectors might disagree. You should always check with someone locally to see if there are any local amendments to the code that they recognize.

When in doubt more protection is better.

Bill