From Allen-Bradley Pub. 1770-4.1
Isn't ising the equipment ground in effect connecting to an electrode?I see in the AB drawing they require a connnection to an electrode where the NEC allows the incoming equipment ground in place of the electrode.
Rick
I think you missed my point. An EGC in a typical premises wiring system is in effect connected to the grounding electrode system (i.e. the EGC provides a low-impedance path to the GES).Yes it is but currently only allowed to be used with transformers 1000va or less. Why would AB require an electrode if not nec required. I don't see a significant amount of control transformers needing to be any larger than a 1000 va.
Rick
Aye...I understood what you were saying. The equipment ground conductor is tied to the GES back at the source, but the AB drawing is calling for a "GEC". If the drawing didn't call it a GEC and just said connect it to the GES, i would agree that the equipment ground conductor is satisfying the requirement.
Aye...
...but it appears, though not noted, the xfmr is over 1000VA and qualifies as an SDS.