> Adding a second grounding rod anywhere else would violate code in most states and potentially create a grounding loop and fire hazard.
Can you cite the relevant portion of the code? Or, for that matter, can you explain why exactly a ground loop is a fire hazard? If this was a hazard, then buildings would burn down when a grounded metallic conduit was buried underground (perfectly legal and very common, although dubiously wise if the conduit is galvanized steel), when anything conductive and connected to building ground (an outdoor appliance, a person touching a switch, etc) touched the ground, or in any building with an associated ordinary in ground swimming pool (which is extensively bonded and generally grounded at the pool equipment pad).
Now you do need to avoid connecting neutral to ground in more than one place if you are a modern NEC-following project or a utility in California, for quite good reasons, but those reasons aren’t a “ground loop” or really a fire hazard — it’s because intentionally running current through a circuit that parallels a path through ground will make a fraction of that current flow through the ground, with potentially unfortunate consequences.
