Buried PVC conduit question - Electrician Talk - Professional Electrical Contractors Forum

Steel Raider · 05-23-2009, 11:39 PM

My father in law is building a garage next to his house and wants to put in a 50amp subpanel in the garage. What is the depth that the conduit has to be buried? I looked at 300.5 and it is sort of vague. Any help would be appreciated. His neighbor already ran the conduit from the house to the garage and its only down about 8" (1 1/2"). This doesn't seem right to me.

Oh, and is a subpanel considered a "service" as far as the code goes?

william1978 · 05-23-2009, 11:43 PM

Thats not deep enough. What did you come up with?

william1978 · 05-23-2009, 11:45 PM

It should be atleast 18" deep.

480sparky · 05-23-2009, 11:45 PM

I don't see how T300.5 can be called vague. You simply draw two lines.... a vertical one in line with Type of Wiring Method or Circuit, and a horizontal one along Location of Wiring Method or Circuit. Where they meet is your answer.

Dennis Alwon · 05-24-2009, 06:42 AM

Quote:

Originally Posted by william1978

It should be atleast 18" deep.

It really depends on the conduit. I seriously doubt that they ran Rigid but if they did then the 8.5' is enough unless it is under the driveway. I bet the neighbor is not a licensed guy.

Bob Badger · 05-24-2009, 07:48 AM

Quote:

Originally Posted by Dennis Alwon

It really depends on the conduit. I seriously doubt that they ran Rigid but if they did then the 8.5' is enough unless it is under the driveway. I bet the neighbor is not a licensed guy.

Eight an half feet?

Yeah that should do it.

Dennis Alwon · 05-24-2009, 07:53 AM

Quote:

Originally Posted by Bob Badger

Eight an half feet?

Yeah that should do it.

I thought so also.

I guess I was thinking about the .5 being a half of a foot. Duhhhh

Chris Kennedy · 05-24-2009, 08:12 AM

Quote:

Originally Posted by Steel Raider

His neighbor already ran the conduit from the house to the garage

Quote:

Originally Posted by Bob Badger

Eight an half feet?

Yeah that should do it.

Your father in law lives next door to this guy???

Podagrower · 05-24-2009, 08:16 AM

Don't forget to strap that PVC in the ground.

I'm not kidding, there is no exception for strapping in the ground.

paul d. · 05-24-2009, 08:23 AM

sometimes , due to existing conditions encasing conduit in concrete will satisfy inspectors/ specs. we run into this problem a lot in water treatment plants.

rexowner · 05-24-2009, 11:08 AM

You may want to look at 225.39, specifically (D). You may
want to make it a 60A subpanel if a CB in the subpanel
is the disconnect in the building.

william1978 · 05-24-2009, 11:11 AM

Quote:

Originally Posted by Dennis Alwon

It really depends on the conduit. I seriously doubt that they ran Rigid but if they did then the 8.5' is enough unless it is under the driveway. I bet the neighbor is not a licensed guy.

Yes that is correct but in the OP question he is talking about PVC conduit.

TOOL_5150 · 05-24-2009, 05:43 PM

Quote:

Originally Posted by Chris Kennedy

Your father in law lives next door to this guy???

That is a messy trench. I use to work with some operators that could step the trench, and excavate it so that it looked like it was done with a knife. Granted, It looks like the dirt is very soft, but it could have a better bevel.

~Matt

erics37 · 05-24-2009, 07:53 PM

Quote:

Originally Posted by Chris Kennedy

Your father in law lives next door to this guy???

Hey that trench looks deep enough to require proper shoring and support, per OSHA requirements. :

lol

Steel Raider · 05-24-2009, 08:07 PM

Thanks for the replies. My father in laws neighbor is not an electrician, and my FIL isn't getting anything electrical in the garage now. He is just getting the conduit from the house to the garage before everything is backfilled. He is getting it inspected before it is covered. It didnt' seem deep enough to me, so I thought I would ask some people that would know more than me. I am not an installation type electrician. I guess you could call me a repair man; i work on DC cranes, VFD's, PLC's, and motor controls.

On another note; does the garage need its own ground rod, or not?

william1978 · 05-24-2009, 08:30 PM

Quote:

Originally Posted by Steel Raider

On another note; does the garage need its own ground rod, or not?

Yes. Here where I live you would need 2 ground rods.

micromind · 05-24-2009, 09:44 PM

Funny how soils are different for different areas. Around here, I don't think I've ever had a ground rod test out at more than 5 ohms.

Rob

william1978 · 05-24-2009, 10:03 PM

Quote:

Originally Posted by micromind

Funny how soils are different for different areas. Around here, I don't think I've ever had a ground rod test out at more than 5 ohms.

Rob

Your correct here I don't think with 2 ground rods it still not below 25ohms.

billsnuff · 06-04-2009, 01:16 PM

office = new construction

earth ground = UFER

(20' #4 copper CEE)

no rods

dmanola7 · 06-04-2009, 11:39 PM

Quote:

Originally Posted by Steel Raider

My father in law is building a garage next to his house and wants to put in a 50amp subpanel in the garage. What is the depth that the conduit has to be buried? I looked at 300.5 and it is sort of vague. Any help would be appreciated. His neighbor already ran the conduit from the house to the garage and its only down about 8" (1 1/2"). This doesn't seem right to me.

Oh, and is a subpanel considered a "service" as far as the code goes?

Look @ Column 3 on Table 300.5 Nonmetallic raceways listed for direct burial without concrete encasement or other approved raceways. The depth is 18". Thats if you are using PVC.