How Deep Does A Ground Wire Have To Be Buried According To The Nec Code Book?

Question

How Deep Does A Ground Wire Have To Be Buried According To The Nec Code Book?

4 Answers

Answer Question

Answer 1

I am going to run 2224 direct burial 100 am wire to a boat house that I will encase in schedule 40 conduit. How deep must I dig the trench to be legal? I have run into a huge rock seam that I cannot go around and can only dig 8 inches deep. Can I add dirt on top of the line equivalent to 2 feet and be legal?

Answer 2

Anonymous answered

The ground wire needs to be at least 18" below the surface, when attach the the ground rods, as previously mentioned.

Answer 3

Well, ground RODS are 8 and 10 feet in length and I'm sure the minimum is 8 feet. You drive the ground rod down then attatch the ground wire to the top of it using a specially made clamp.

Answer 4

My 1971 NEC book says "pipes or rods shall be driven to a depth of 8 feet regardless of size or number of electrodes used." A rod electrode of steel or iron is required to be at least 5/8" in diameter. Other dimensions apply to pipe or other rod materials. Each electrode must be at least 6 feet from any other. If it is less than 4 feet to "rock bottom," the rod must be buried in a trench.

It appears that metal water pipes are the preferred grounding technique, followed by metal gas pipes if the utility agrees. Driven pipes or rods are least preferred in that version of the code.