What is the difference between metal wire trough and cable tray? Can anyone tell me?

Cable trunking is a subcategory of bridges, just like cars, which include cars, trucks, buses, etc. Cable bridges refer to a combination of brackets, accessories, supports and hangers, etc.; among them , the bracket body can be divided into: non-hole, hole, ladder rack, combination tray and other forms. Metal trunking, more often referred to as sealed steel cable trays (optional with covers), can be used to lay wires and cables. Since it is a closed steel shell, it has a certain shielding effect, and weak wires or control The lines mostly use trough type bridge. (In addition, plastic wire ducts and bus ducts are different from those mentioned here). In engineering, trough type cable tray is often referred to to avoid being distinguished from products such as bus ducts.