Metal cable trays are generally suitable for overhead installations in indoor spaces under normal conditions. Due to the fact that metal conduits are typically made from steel plates with a thickness of 0.4 to 1.5rhm, their structural characteristics dictate that metal conduit wiring should not be used in locations where there is severe corrosion of the metal conduits.
Closed metal conduits with slot covers, offering fire resistance comparable to metallic conduits, are suitable for installation in building ceilings.
Plastic cable trays are generally suitable for open installations in indoor spaces with normal environments, as well as for projects in scientific research laboratories or precast structures where concealed installations are not possible; they are also used for replacing wiring in existing projects; and they are also suitable for concealed installations in suspended ceilings for low-voltage wiring.
Metal Conduit and Grounding:
Metal conduits must have a reliable electrical connection with PE or PF.N cables, and Nanchang Bridge Support Factory complies with the following regulations:
Metal conduits shall not be welded across to connect grounding wires.
(2) Metal wire grooves should not be used as grounding conductors for equipment. When no design requirements are specified, the entire length of the metal wire groove should be connected to the PE or PEN cable trunk at least twice.
(3) The non-galvanized metal cable tray connection plates are bridged at both ends with copper core ground wires, with a cross-sectional area of not less than 4mm2. The galvanized line slot connection brackets do not bridge the ground wires at both ends, but both ends of the connection plates have at least two connection screws with anti-loosening nuts or anti-loosening washers.
