ECN Forum Forums General Topics of the Trade General Discussion Area Fluke 1735 and Neutral to Ground Voltages

Typically they tell you to connect the IG to the same spot in the service disconnect enclosure where the MBJ lands.
For the NEC purposes a Ufer is a pretty good electrode but I would not count on 30' of that rusty rebar to give you a single point ground. There are at least 2 wire tied joints in there.