DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Electrical (http://www.diychatroom.com/f18/)
-   -   Burial deptch PVC conduit (http://www.diychatroom.com/f18/burial-deptch-pvc-conduit-5006/)

Manuel6 11-25-2006 03:38 PM

Burial deptch PVC conduit
 
What is the minimum burial depth for pvc conduit on a 20-amp outdoor circuit GFCI protected at the outdoor, main panel?

Thanks.

mdshunk 11-25-2006 03:43 PM

Twelve inches.

NEC Table 300.5

concretemasonry 11-25-2006 06:43 PM

The code is a minimum.

In real life, the areas around a house get regraded and excavated, so you can have problems doing as little as possible.

One cheap method to alert people and to protect a burried line is to lay some cheap 2x8x16 patio stones over the pipe when you backfill.

Speedy Petey 11-25-2006 09:15 PM

The OP did ask what the minimum was. So 12" is the correct answer.

If the circuit was not GFI protected before it went underground, the minimum burial depth would be 18".

These numbers are to the top of the pipe. The term is "Minimum Cover Requirement" not actually burial depth.

In the case of 12" I do like the patio stones idea though.

mdshunk 11-25-2006 10:40 PM

Quote:

Originally Posted by Speedy Petey (Post 24769)
These numbers are to the top of the pipe. The term is "Minimum Cover Requirement" not actually burial depth..

Right. You could technically lay the conduit on top of the ground and throw a 12" mound of dirt on top of it. That woud fulfill the 12" cover requirement.

Speedy Petey 11-25-2006 11:02 PM

No, we've never had to do that. :whistling2: Why would you even suggest such a thing. :whistling2:

concretemasonry 11-25-2006 11:07 PM

Burial deptch PVC conduit
 
Some people want to do it by code, which is the least you have to do and get by. - Don't ask me why unless they are either lazy when they do it or cheap when paying someone else to do it.

Maybe they don't think they did it right and want to make ir easy to fix?

Speedy Petey 11-25-2006 11:11 PM

What is your point? Are you implying doing things to code is not enough?

Speedy Petey 11-25-2006 11:13 PM

Of course overkill is sometimes necessary, but code minimum is always at least safe.

mdshunk 11-25-2006 11:43 PM

Quote:

Originally Posted by concretemasonry (Post 24786)
Some people want to do it by code, which is the least you have to do and get by.

Correct. The code is a minimum set of standards. Feel free to bury your conduits 20 or 30 feet deep, if that pleases you more. The NEC has been continuously improved since its first edition in 1897. I think that if there was some special safety issue regarding the minimum cover depths, it would have been adjusted by now. Mind you, there's a whole chart of minimum cover depths for various circumstances. Some of them are much deeper. The original poster inquired about a 20 amp GFCI protected circuit in PVC conduit, and his answer was tailored as such.

mdshunk 11-25-2006 11:44 PM

Quote:

Originally Posted by Speedy Petey (Post 24784)
No, we've never had to do that. :whistling2: Why would you even suggest such a thing. :whistling2:

I know I've wired up a few job trailers that way in the past. I've even done new services that way, when the grade is being brought up dramatically anyhow.

jwhite 11-26-2006 05:28 AM

Quote:

Originally Posted by mdshunk (Post 24779)
Right. You could technically lay the conduit on top of the ground and throw a 12" mound of dirt on top of it. That woud fulfill the 12" cover requirement.

I have done this too when I knew grade was comming up. On on job my conduits ended up six feet below grade.

Manuel6 11-26-2006 02:19 PM

What controversy
 
Wow! I never would have expected that "minimum cover requirement" ("burial depth" to us less versed) would have sparked such an exchange. I asked the question because I like to plan projects with safety in mind, and since the NEC is primarily in the business of safety, I figured an professional electrician familiar with the NEC could give me the correct, and presumably, safe answer. Although, I will admit that safe by the NEC, or any other building code in any of other trades, is not always best. You do, of course, have to consider other factors such as convenience and application. In my application, I simply want two duplex receptacles in the front of the house that will permit my wife's extensive christmas lights to go up without any problems. We had a receptacle out front, but the circuit is dead for reasons unknown. And since the cable runs behind finished falls and through voids in concrete block, trying to find the problem is more of a hassle than just simply replacing it. The conduit run I'm planning will go by the front of the house underground about twelve feet (did I mention the wires would be protected in conduit for the whole run????), make a left turn at the corner about two feet, and go up to main panel outside...pretty innocent project. However, that does not mean that I don't want to pay attention to those vital details that make a difference- for example "minimum coverage". Running conduit horizontally on grade and covering it with 12" of florida sand, although acceptable, will not probably work. Three summers from now, and 50 wind driven rainstorms later, will make that 12" mound a 4" mound of sand. Likewise, burying conduit 3 feet underground on a 20-amp GFI protected circuit seems to be a bit of overkill, no matter how lazy or stong your back may be....The likelyhood that you would shovel down more than 12" to plant a bush is slim, and any tree that would require that type of excavation you most likely woudn't want to have growing right next to the house. Additionally, negatively re-grading to the point of actually exposing the slab is not practical for me or any future owner of the house. If anything the elevation of the dirt near the house would be brought up- not down. However, placing stones near the run so as to provide a bit of warning to the person excavating is a pretty clever idea, and I think I will do that.

Now, my next question is which gun should I buy to protect my family a 9mm beretta or a smith and wesson 357 magnum...Just kidding! :thumbup: Thanks for all the input guys...take it easy!

joed 11-26-2006 07:19 PM

Did you check all the GFCIs for the problem with the dead receptacle. It is most often in the garage behind the pile of stuff you never move.

Manuel6 11-26-2006 09:55 PM

To Joed
 
I pulled the receptacle off. The wire has no power. The entire house has power, no breakers trip, all receptacles and all GFI's work properly in all the rooms. I think that during a remod, somebody may have rewired something, or cut the cable, that killed that branches power...I don't know.... I've checked everything and haven't been able to find anything apparently wrong.


All times are GMT -5. The time now is 10:18 PM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved