Alternative to ground rods or Ufer

[Scott’s Power & Electric]

I work in an area that has a bunch of pole mounted services. Many locations it is nearly impossible to drive a ground rod even 4’ into the earth.
There seems to be little or no conversation on alternatives to the two ground rods we all use.
Even the supply houses act as if no other options exist.
What are some options you all have used when rods or uffers are not an option.

 

[infinity]

A ground plate is a good option. Only issue is it requires someone to dig a decent size hole at least 30"+ deep.

 

[hillbilly1]

How far away from the pole is the building? Possibly a ground ring? Or if the ufer is available, it can be ran back to the pole. As far as I know, there is no restriction on how far away the grounding electrode is.

 

[Scott’s Power & Electric]

Most often this situation is where there is a modular or mobile home. The distance can be as close as 5’ or as far as 50’.
My first thought is a plate. As the previous response said it is a size able hole. If I’m recalling correct 2’x2’(maybe 3’x3’) for the plate itself and a short trench to service pole. The plate I believe needs to be 36” deep(again if I recall correctly) Not many inspectors are familiar with the specs either.
I know there are some Roto hammer bits that allow to drill out a hole for that 8’ rod also. Still difficult in a boulder rich environment.
My fear with the bit is buying it and getting it stuck on my first use.

 

[infinity]

If I’m recalling correct 2’x2’(maybe 3’x3’) for the plate itself and a short trench to service pole. The plate I believe needs to be 36” deep(again if I recall correctly)

Plate electrodes can be as small as 12"X12". They are required to be buried at least 30" deep and you would need two unless a single plate electrode is tested to 25Ω or less. It's one of those things where you could dig the two holes in 5 minutes if you had a backhoe.

250.52(A)(7) Plate Electrodes.
Each plate electrode shall expose not less than 0.186 m2 (2 ft2) of surface to exterior soil. Electrodes of bare or electrically conductive coated iron or steel plates shall be at least 6.4 mm (1∕ 4 in.) in thickness. Solid, uncoated electrodes of nonferrous metal shall be at least 1.5 mm (0.06 in.) in thickness.

250.53(A)(5) Plate Electrode.
Plate electrodes shall be installed not less than 750 mm (30 in.) below the surface of the earth.

 

[don_resqcapt19]

A ground plate is a good option. Only issue is it requires someone to dig a decent size hole at least 30"+ deep.

Probably two holes as the same rule that applies to rods, applies to plates.

 

[infinity]

Probably two holes as the same rule that applies to rods, applies to plates.

Correct. I mentioned in post #5. I wonder if a single plate electrode would be closer to the 25Ω or less than a single rod.

 

[electrofelon]

I work in an area that has a bunch of pole mounted services. Many locations it is nearly impossible to drive a ground rod even 4’ into the earth.
There seems to be little or no conversation on alternatives to the two ground rods we all use.
Even the supply houses act as if no other options exist.
What are some options you all have used when rods or uffers are not an option.

Note you don't have to drive the rod vertical. If you encounter rock, you can lay in a 30-in deep trench. In practice, I wouldn't dig a trench I would just drive it at a shallow angle as necessary.

 

[CoolWill]

A 7" cube has the right numbers. I wonder if anyone has tried that? Two 8" auger holes, 30" deep and 6 feet apart. Toss in a couple of 7"x7"x7" cubes... Boom... Grounded.

 

[LarryFine]

Anyone have some spare 7" copper cubes?

 

[CoolWill]

Anyone have some spare 7" copper cubes?

Do they have to be copper?

 

[Fred B]

Note you don't have to drive the rod vertical. If you encounter rock, you can lay in a 30-in deep trench. In practice, I wouldn't dig a trench I would just drive it at a shallow angle as necessary.

Code does allow for driving at an angle up to 45^o or a trench and horizontal lay of the rods, that would require 16 ft of trench. Did have one that only made a 10ft and 2-2.5ft to bedrock trench and drove the rod horizontally on the bed rock surface in either direction, 2 full rods and 6ft spacing as a result.

 

[infinity]

Do they have to be copper?

No, you can used steel for plate electrodes. Although it may have enough soil contact I don't think that a cube meets the definition of a plate. I do like the out of the box thinking.

 

[electrofelon]

Code does allow for driving at an angle up to 45^o or a trench and horizontal lay of the rods, that would require 16 ft of trench. Did have one that only made a 10ft and 2-2.5ft to bedrock trench and drove the rod horizontally on the bed rock surface in either direction, 2 full rods and 6ft spacing as a result.

Right, just to be clear, I would NEVER drive a ground rod in at less than a 45 degree angle, and then maybe bend the end up to 45 or more to make it look cold compliant.

 

[CoolWill]

Right, just to be clear, I would NEVER drive a ground rod in at less than a 45 degree angle, and then maybe bend the end up to 45 or more to make it look cold compliant.

Yeah, I wouldn't do that either last week.

 

[Greentagger]

As Hank Williams sang” There’s a tear in my beer……” after hearing all this.

 

[NTesla76]

Right, just to be clear, I would NEVER drive a ground rod in at less than a 45 degree angle, and then maybe bend the end up to 45 or more to make it look cold compliant.

Because everyone knows that 45 degrees is the magic angle.

 

[mtnelect]

Never leave short sections of a ground rod on the job !

 

[NTesla76]

Never leave short sections of a ground rod on the job !

I was on an inspection and the contractor did this. I handed the cut off piece to him.....the look on his face was priceless.

 

[jaggedben]

Never leave short sections of a ground rod on the job !

Also don't cut off the part in the ground at an angle.