Wiring in the ground

I got a call today asking how far in the ground does electric conduit need to be installed. This electric was running to the garage from the house and was installed only a few inches down. Of course, we do not determine how far electric is installed in the ground but I would like to know for myself.

If there is a minimal depth requirement, does anyone have the code for that?

Thanks ahead of time.

Hello Kevin,
Not sure about “code”, but when I built my home, the (underground) SE from the road to the transformer was min. 30"…and the (underground) conduit to the garage and other outbuildings was min. 18"…(in 1998).

UF Cable generally requires 24" of cover whereas rigid metallic conduit can be as little as 6". There are quite a few variables. . .

There are many depth requirements, ranging from 6 inches to 24 inches, depending on type of conduit, type and size of circuit, and location of the run.

whoops wrong thread

I think you posted that in the wrong thread :wink:

Dude…if you are just looking for Depths and a Code Reference…NEC 2005 See Section 300.5

I guess I need a little help understanding this Section. Column 1, 2, 3 and 5 I understand. Column 4 is where I’m a little confused.

It’s written “Column 4 Residential Branch Ciurcuits Rated 120 Volts or Less with GFCI Portection and Maximum Overcurrent Protection of 20 amperes”. It reads that “All locations not specified below” in the “location of Wiring Method or circuit” applies, then burial of 12 inches is needed. Now, Column 1 is for direct burial cables or conductors, column 2 is for rigid metal counduit or intermediate metal conduit, Column 3 is for nonmatallic raceways listed for direct burial without concrete encasement or other approved raceways and column 5 is for circuts for control of irrigation and landscape lighting limited to not more than 30 volts and installed with UF or in other identified cable or Raceway.

Could collumn 4 fall under wiring going to a detached garage where the outlet in that garage is protected by a GFCI breaker?

Yep…unless it applies to any of the locations that are indeed listed below.

For example it could actually be 6" or 4" as well as the 12" you are seeing…if the conditions of the allowance listed.

Just to make sure I have this right. If you had 120 volt circuit protected by a GFCI breaker going to a detached garage in Non metallic Raceway, then the 18 inch burial (column 3, first row) is then reduced to 12 inches (column 4, first row). And if the circuit is in rigid metal conduit, then it doesn’t matter if it GFCI protected, the depth is 6 inches (column 2, first row).

If the above information is correct, I feel I understand this table completely.

Correct…however in your example chances are the circuit run to the detached garage would be GFCI anyway…:slight_smile: if there is power in the detached garage the receptacles have to be GFCI protected.

But without looking back I think you have it.

But Paul I believe the CIRCUIT must be GFCI protected. So the GFCI in the garage wouldn’t cut it, you’d need a breaker at the beginning of the circuit to qualify for 12" depth.

my statement was that if he did have receptacles in a garage ( not refering to the depth issue ) that they would need to be GFCI…not that the circuit could be protected with a GFCI receptacle versus a GFCI breaker…I was simply refering to IF he had a garage that was detached…to not forget the receptacles would need to be GFCI protected…as a general statement.

See my statement…it would GFCI anyway because of his using 20A GFCI option for depth…so I was being kinda MOOT on the GFCI requirement within the garage…it would kinda cover it in the first instance…get my drift.