Ground elwronc. cannot b. more than 1/5 7. Device must bar ... These general requirements are referred to in the chart as aquot;Basic. ... Under the heading aquot; Vehicles Affected, aquot; the word aquot;AHaquot; includes trucks, tractors, trailers, semi-trailers, pole trailers and buses. ... Devices must be of a type approved by the Commissioner of Safety, Lampl, wiring or reflectorized material must not be attached to the flaps. _ 9.