I am confused by the process of "grounding the can. NEC and my friendly neighborhood electical inspector say, "put the green bonding screw in the neutral bus." How does that ground the can? It looks like to me that the neutral bus is insulated from the can by the piece of plastic underneath it. Can you help me understand? Thanks for any help you can offer. Les
That little green screw is made of metal, most metals are reasonably good conductors of electricity. When you run the screw through the proper hole in the neutral bus, (there will be a hole through the plastic at this point) it will thread itself into a hole in the can and the head will make contact with the bus. Now the neutral bus is no longer isolated from the enclosure.