Lamp Post

[infinity]

Anyone want to take a stab at this question?

A lamp post at a dwelling is fed underground with a 120 volt, 15 amp GFCI protected circuit run under a driveway. What is the permitted wiring method?

a) UF cable buried 12” deep
b) PVC conduit buried 12” deep
c) Rigid Metal Conduit buried 6” deep
d) All of the above
e) a) or b)

 

[tom baker]

Sorry we don’t answer test questions.
But if you asked your supervisor, they would say e)

 

[augie47]

how about an (f) selection: none of the above (based on the driveway)

 

[Little Bill]

That old guy above stole my answer!

 

[Little Bill]

Wait, I change my answer based on it being a dwelling, so E!

 

[Greentagger]

E

 

[infinity]

Yes, the correct answer is supposed to be e). This is from a practice test that I'm writing for a fellow electrician who is studying for a licensing exam and in answering the question I've always found parts of the table to be confusing. The interesting part of Table 300.5 is the note #4 which can trick one into thinking that for RMC a 6" burial depth could apply but it actually would not apply since one of the other conditions listed in the table (under a dwelling driveway) is within the question. I guess one could argue that the question should say 1 or 2 family dwelling (in my head it was implied) which may have led to Augie's answer.

4. Where one of the wiring method types listed in Columns 1 through 3 is used for one of the circuit types in Columns 4 and 5, the shallowest depth
of burial shall be permitted.