The use of cable tray is more frequent in some outdoor areas, which is mainly used for cable erection. Its use is conducive to the protection of the cable and plays a greater role. Because of its wide use and unfixed use, there are many different types of cable tray, including long-span, galvanized cable tray, fireproof cable tray, etc. There are many styles, and the later installation is relatively simple. So, which aspects should we start from when building the cable tray? Let's have a look.
1、 Configuration of supports and hangers
1. The short span of indoor support and hoisting is generally 1.5-3m. The middle span of outdoor column is generally 6m.
2. The support and hanger configuration of non-linear section follows the following principles. When the bridge width is 300 mm, a support and hanger shall be set at the side of the straight section 300-600 m away from the joint of the non-linear section and the straight section. When the bridge width is 300 mm, in addition to the following conditions, a support and hanger shall be added in the middle of the non-linear section.
3. When the cable tray is set in multiple layers, the distance between layers is 200250300350mm.
4. 20-30mm expansion joint (metal bridge) shall be reserved for the straight section of cable bridge every 50m.
2、 Fire prevention
Steel or non combustible and flame retardant materials shall be used in the section where the bridge is required to be fireproof.
1. The bridge system shall have reliable electrical connection and grounding (only for metal bridge).
2. When the bridge system is allowed to form the grounding trunk circuit, the following requirements shall be met. The connection resistance between bridge ends shall not be greater than 0.00033 ohm, and the insulation coating shall be removed from the grounding hole. In the 1kV and below neutral point direct grounding system, the grounding of the receiving equipment is connected with the neutral line of the system. When installing the dynamic cut-off power supply installation, the metal cross-sectional area in the direction of the bridge length shall not be less than the specified value.
3. When another grounding main line is laid along the whole length of the bridge, at least one point of each section (including non-linear section) of the bridge shall be reliably connected with the grounding main line.
4. For vibration place, spring coil should be installed at the connection of grounding part.
The above are several aspects that should be paid attention to in the construction of cable tray. The bracket or hanger should be set when the cable tray is installed, so as to ensure the correct installation of the cable tray. In addition, the grounding connection should also be paid attention to when carrying out the grounding work, so as to prevent affecting the use of the cable tray.