Ground Rods

[kkober@tsinc.cc]

I work in the oilfield and wanted to know the code for installing our ground rods on our equipment.
We move mobile homes to various locations & install water pumps & sewer pumps to our living quarters. We also power up our equipment through our Portable Generators. What depth & distance from our houses and equipment does the ground rods need to be?

Thanks,
Kyle

 

[zbang]

We also power up our equipment through our Portable Generators. What depth & distance from our houses and equipment does the ground rods need to be?

Don't know about oil-field specifics, but the minimum distance from grounding electrode to structure is zero feet. To avoid pulling specific sub-article numbers, you really ought to read all of article 250.

For instance 250.52(A)(5) says:

(5) Rod and Pipe Electrodes. Rod and pipe electrodes shall not be less than 2.44 m (8 ft) in length and shall consist of the following materials.
(a) Grounding electrodes of pipe or conduit shall not be smaller than metric designator 21 (trade size 3⁄4) and, where of steel, shall have the outer surface galvanized or otherwise metal-coated for corrosion protection.
(b) Grounding electrodes of stainless steel and copper or zinc coated steel shall be at least 15.87 mm (5⁄8 in.) in diameter, unless listed and not less than 12.70 mm (1⁄2 in.)
in diameter.

See 250.35 and 35 for generators, 250.32 for feeders supplying structures, etc. Pay attention to the main bonding jumper- if the generator is supplying multiple structures, it should be at the generator and no where else.

Also, take a look at articles 550, 552, and 590.