I thought everybody might find this interesting, this was the response from NFPA to our DCA in reference to 3 wire or 4 wire supply side connection,
Thank you for your email concerning the National Electrical Code@.
After consulting with the team here are NFPA we are in agreement that the PV system disconnect should not be bonded, an insulated grounded conductor would be required and the equipment grounding conductor carried back to the point of connection.
Regards,
Gil Moniz
Senior Electrical Specialist
National Fire Protection Association
I Batterymarch Park
Quincy, MA 02169-7471
617-770-3000