Is ufer ground available?

[DOUGPVE]

Starting a new 4-story bank, full basement. footings, 13' concrete walls, and 20" slab is all below grade but is not in contact with the earth because of complete waterproofing of the
basement. A thick waterproofing material has been installed under and around all portions of the building below grade. Typically we connect to the rebar, this building has miles, but in this case all I would accomplish is bonding the steel, I hate to have a 2000amp 480V service grounded with only two ground rods. Just so you know, all the concrete work is being done prior to MEP drawings being released. Inspector and Engineer are not sure what to do, any thoughts?

 

[dicklaxt]

My first thoughts would be to treat it as tho it was an installation back before Ufer gounds became very popular,,,,,,that would be multiple rods and a grid tied off at the building steel at all 4 corners as a minimum.I can be easily made to change my mind tho

dick

 

[kwired]

I can see floors or walls being insulated, waterproofed, etc. but is the footing isolated from the earth? Usually it is not, and that is why the footing is the preferred place to connect a CEE.

Doesn't matter if you have a 30 amp service or a 3000 amp service, two ground rods is sufficient for NEC if there is no other electrodes naturally present. You can put in 10 ground rods and likely will not see much enhancement over what you will get from 2.

These electrodes do not care that you have a 2000 amp service - they are not intended to interrupt fault current or carry any normal operating current, they are intended to stabilize voltage between grounded conductors and earth, and to dissipate transient voltages to earth.

 

[infinity]

If the footings are not in contact with the earth then you do not have a CEE. If no other electrodes are present then 2-8' rods are all that you'll need.