Many a chase nipple I have installed wrenchtight into an LB still rattles against the enclosure. There is no way this is providing the "effective ground fault current path" as required by 250.4(A)(5).
The UL listing of reducing washers as a proper ground, sticks in my craw. I will have to digest this for awhile. UL does add: "where installed in accordance with" the NEC.
250.96(A) requires: Metal parts are to be "effectively bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any nonconductive paint, enamel or similiar coating shall be removed" or replaced with grounding fittings.
