Re-bar ground required in Precast?

[dereckbc]

250.50 states "All grounding electrodes as described in 250.52(A) (1) through (A) (7) that are present at each bldg or structure served shall be bonded together to form the grounding electrode system.

Right there is your answer, and your misunderstanding of the requirement. The rebar is NOT PRESENT and/or accessible. Therefore not required to be used.

Now if he was pouring the pad, then the rebar is Present and shall be used.

 

[suemarkp]

Don't think that argument will work. When this UFER wording first went into the code, many a contractor here had to jackhammer up a portion of a slab because he didn't leave an accessible tail on the rebar to ground to. That seems to match the gist of the letter iwire posted for Mass too. Here, they said if there was suitable rebar and the required minimum length, you had to use it. Your only way out would be to use plastic coated rebar, put plastic under the concrete so it wasn't in direct contact with the earth, or don't install rebar in the first place.

The "not in contact with the earth" may be a way out for him -- can these precast piers (or whatever they are) be put on top of plastic sheeting?

 

[GoldDigger]

The "not in contact with the earth" may be a way out for him -- can these precast piers (or whatever they are) be put on top of plastic sheeting?

Applying a foundation wall type waterproofing coating would work too, and might even be justifiable in terms of preventing wicking of water up the columns.