C_Hill
Member
- Location
- Sonora, Ca. U.S.
For a 200 amp service, resi., 5/8 by 8' is required. Does a 400amp/320 continuous service require a 3/4 by 10' electrode? I feel like this was something that I had heard about. TIA!
For a 200 amp service, resi., 5/8 by 8' is required. Does a 400amp/320 continuous service require a 3/4 by 10' electrode? I feel like this was something that I had heard about. TIA!
But Where in the NEC does it reference the size and depth of the Ground Rod?
250.52(A)(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) Rod-type 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.
250.53(G) Rod and Pipe Electrodes. The electrode shall be installed
such that at least 2.44 m (8 ft) of length is in contact with the
soil. It shall be driven to a depth of not less than 2.44 m (8 ft)
except that, where rock bottom is encountered, the electrode
shall be driven at an oblique angle not to exceed 45 degrees
from the vertical or, where rock bottom is encountered at an
angle up to 45 degrees, the electrode shall be permitted to be
buried in a trench that is at least 750 mm (30 in.) deep. The
upper end of the electrode shall be flush with or below ground
level unless the aboveground end and the grounding electrode
conductor attachment are protected against physical damage as
specified in 250.10.
For a 200 amp service, resi., 5/8 by 8' is required. ...
Not if the rod is listed.
In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?
When I was a helper, our boss (mom'n'pop shop) always had us drive 3/4" RGS as electrodes . . . with a sledge hammer.In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?
In what situations one might install 3/4 by 10' ground rod instead of 5/8 by 8' ground rod?
No, the service can be 6000 amps and the ground rod only needs to be 5/8" x 8' or 1/2" by 8' if listed. BTW, welcome to the forum
To meet some silly job spec.
I'm glad I found this answer, I've been searching all over the internet and my ( 2014 NEC) , I know get the latest version .. , and all I found was 250-52 (5) (b) stating the 5/8" rod is approved .. what's with the "unless listed clause" anyway I'd sure like to get a real instance of when that 3/4" inch rod would be required other than a engineers spec.
I'm sure your right but it's got to have a place somewhere ... one would think. .. I'll followup if I ever decide to spend more time on the mystery ground rod.
Thank you. Sincerely, Mark
Ok But ... were would that 3/4" rod be commonly found, maybe its designed for more surface area in a less conductive soil composition ..?The customer has the money and asked for it.
Its the only rod you have on the truck.
Job specs.
You’ve had it in the shop for years and are tired of looking at it because you are reminded of that one and only time you goofed up?
By code, you would still need at least two, unless that extra surface area got you the 25 ohm. Threaded, they would be used for deep earth.Ok But ... were would that 3/4" rod be commonly found, maybe its designed for more surface area in a less conductive soil composition ..?
250.52(A)(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) Rod-type 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.
Although the only time I’ve driven 3/4”x10 ‘ rods was quite some time ago when the job specs or if we were doing a 400 amp service would do the 3 rods in a triangle. Silly wasn’t it, just how eluding the grounding requirements really were when learning from one person to another.