Many people ask if all bus ducts are waterproof.In fact,waterproof bus ducts can be sealed by pouring,while other bus ducts,including fire-resistant ones,cannot be waterproof.Waterproof busbar trunking models are generally classified into dense or air type,with specifications classified according to the current size.However,there are not many people who use this type of busbar trunking because although the overall waterproof effect is good,maintenance is more complicated,and because it is fully solid enclosed,it is easy to be exploited by people.

　　The fire-resistant busbar trunking consists of an outer shell coated with fire-resistant paint,busbars wrapped with fire-resistant mica tape,and brackets made of fire-resistant insulation materials.The fire resistance time of fire-resistant bus ducts is usually 60 minutes or 90 minutes,mainly due to the fireproof treatment of the outer shell and the lining of corresponding refractory materials inside.It is a non-metallic shell bus duct,which is made of high-performance insulation material by mixing special composite resin and quantitatively selected mixed materials.The copper bus is directly poured and sealed.There is no air gap,no chimney effect,and busbar burrs or overloads will not cause short circuits.

　　For wide busbar main lines,the number of straight units tested can be reduced,but in this case,the three test arrangements should be repeated(considering the direction of the shell side).For busbar main lines with tap devices,the test arrangement should face the outlet end of the tap device towards the burner,and the tap device installed as in normal use(such as with a cover plate)should be placed directly facing the flame.After the combustion stops,the outer shell of the busbar should be wiped clean,all smoke and dirt should be removed,and the original surface should be intact and undamaged.The softening and deformation of non-metallic materials should be ignored.The large-scale measurement of destruction is measured in meters from the bottom edge of the burner to the starting point of burning.

　　A representative sample of the busbar main fire protection unit is placed on a concrete test bench as it is actually used in buildings,and its thickness is determined according to the requirements of fire resistance time.The fireproof sealing layer should be filled around the busbar main shell passing through the test bench opening according to the manufacturer's instructions and the requirements of building safety and fire prevention.If the busbar main system passes through building partitions horizontally or vertically,the design of the busbar main fireproof board unit should prevent flame spread in case of fire.