Lamp Post on GFCI underground UF Burial Depth?

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glene77is

glene77is

Senior Member
Location
Memphis, TN
I have a Lamp Post, plan to use a GFCI on the circuit, and feed underground with UF cable.
What is the burial depth requirement.
I have seen this type of install in the NEC,
and believe I have seen a Mike Holt graphical on it.
I have looked through my Mike Holt books, can't find it.

I recall the depth to be shallow, like 6 inches,
based on GFCI protection.

I would like to use an exterior GFCI receptical,
pipe down,
trench UF across the yard at 6",
pipe up,
into the Lamp Post.

I need to be able to cite the code or install RNMC.

:)
 
Action and Celtic,
Thanks.
That is where I started,
and hoped that someone else had a different clue.

I recall that I was researching the sub-panel options several years back.
I had discussed a 240V circuit,
but the client opted for a "single 120V circuit".
So, I had a single circuit to extend, underground in RNMC, to a tool shop.

I recall arriving at the conclusion
that a "single 120V circuit" could be run without a CB panel,
and
IF a GFCI protected the "single 120V circuit"
THEN UF could be placed underground, and
buried shallow, and
considered fully protected (suitable for a Lamp Post).
(Although I used underground RNMC for the above little job.)

I recall that a 240V circuit required only a Disconnect,
although I have, as a standard, used a small circuit breaker (CB) panel.
(The exception being in my personal tool shop which has a double pole 30A switch.)

As a standard, I use a four wire feed to a tool shop,
and use a small CB panel,
and GFCI control as required,
and a ground rod for detached buildings.

When I misplace something, it runs me in a tizzy.
Guess this is just a bad morning, too much mist.

Thanks,
:smile:
 
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glene77is said:
I have a Lamp Post,
plan to use a GFCI on the circuit,
and feed underground with UF cable.
What is the burial depth requirement.
:)
Click to expand...

Guys,
I'll have to answer my own question here.
this is what I found, finally!

from NEC Handbook, 2005,
"" 300.5 Underground Installations
(A) Minimum Cover Requirements
Direct-buried cable or conduit or other raceways shall be installed
to meet the minimum cover requirementrs of Table 300.5. ""

Blue Comments, bottom of page 259
"" ... However, if the conductors are protected
by an overcurrent device rated at not more than 20 amperes
and provided with ... GFCI ... protection
... the burial depth may be reduced to 12 in.
Exhibits 300.6 and 300.7 ...
""

So, I can wire from a GFCI receptical,
underground through UF 12-2 wg,
at 12 inches,
to the lamp post.

I assume the same would hold true
for wiring a tool shed, with a single 120 volt circuit.
Any comments on the Tool Shed application?

This would open the door to a cheaper method
of wiring to an outhouse tool shed,
if allowed.

Comments appreciated.

:)
 
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This would open the door to a cheaper method
of wiring to an outhouse tool shed,
if allowed.
Click to expand...

It opens the door for problems too.

UF is a poor wiring method for underground installations. Stuff happens to wiring.

PVC is cheap. Use it.
 
iwire said:
I have no idea what you mean, but technically there is no such thing as Article 300.5.
Click to expand...

Fine. Technically, I should say Section 300.5. But technically, everyone calls them Articles and the rest of us really know what I'm talking about.

OK... technically, I'm not talking. I'm typing. Just so you have an idea what I mean.
 
I don't understand what the problem is with sending the OP to the table first. Half a dozen of one, six of the other. The section (aside from (A) which sends you to the table) deals mainly with items other than burial depth, which is what the OP was asking about. :confused:
 
George Stolz said:
I don't understand what the problem is with sending the OP to the table first. Half a dozen of one, six of the other. The section (aside from (A) which sends you to the table) deals mainly with items other than burial depth, which is what the OP was asking about. :confused:
Click to expand...

Thanks, George,

I don't mind being referred to the table, first or last.

I was certain that I saw an exception to the table
(and we always refer to the tables to stay safe).
I just could not find the exception,
and any act of forgetfulness can be dangerous.

So, I was rumaging around in my readings,
and came across the footnote in my 2005 Handbook.
The footnote expresses the "intent" of the NEC.
See my other post for the quotation, please.

And, as a further question,
I do wonder if I could wire a 'tool shed'
as if it were a 'lamp post',
per the quoted text.

:)
 
glene77is said:
Guys,
I'll have to answer my own question here.
this is what I found, finally!

from NEC Handbook, 2005,
"" 300.5 Underground Installations
(A) Minimum Cover Requirements
Direct-buried cable or conduit or other raceways shall be installed
to meet the minimum cover requirementrs of Table 300.5. ""

Blue Comments, bottom of page 259
"" ... However, if the conductors are protected
by an overcurrent device rated at not more than 20 amperes
and provided with ... GFCI ... protection
... the burial depth may be reduced to 12 in.
Exhibits 300.6 and 300.7 ...
""

So, I can wire from a GFCI receptical,
underground through UF 12-2 wg,
at 12 inches,
to the lamp post.

I assume the same would hold true
for wiring a tool shed, with a single 120 volt circuit.
Any comments on the Tool Shed application?

This would open the door to a cheaper method
of wiring to an outhouse tool shed,
if allowed.

Comments appreciated.

:)
Click to expand...

I maybe wrong here but doesnt the blue section start with "Conductors under residential driveways" And exhibit 300.6 shows 12" depth if installed below 2"s of concrete. Not to be redundant but Exhibit 300.7 shows the driveway. Or did I miss that you were putting concrete over the UF. The Handbook does not state only for post lights. My interpretation of the "explanatory text" is the post light would just be one example of the intent of the code. So post light or garage or shop... as long as it is not more than a 20 amp branch circuit GFCI protected.

Still under '05?
 
I can't find a definition of "residential driveway". Mine is gravel??????? Some are grass strips. So is it the intent of the code to allow you to reduce your burial deapth if the driveway is made of gravel?
Also I thought the blue text was only informational and not "code enforcable"? I couldn't find the exception the blue text was explaining??
 
Table 300.5 is one of the more goofy tables in the NEC:D

Line:
In or under airport runways, including adjacent areas where trespassing prohibited
Click to expand...

Is answered in colomn 4, like thats right where I'm going to have my house:roll:

Line:
One- and two-family dwelling driveways and outdoor parking areas, and used only for dwelling-related purposes
Click to expand...

allows just UF to be 12" deep in colomn 4 but if you put it in RMC, colomn 2, will require it down 18":roll:

Someone tell me they changed this in 2008?
 
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