Control cable precautions
1. Insulation electrical strength: 1min between conductors 1kv does not breakdown conductor and shield 1min 3kv does not breakdown
2. DC resistance: 20 ° C, 0.4 mm copper wire, less than or equal to 148 Ω / km, 0.5 mm copper wire, less than or equal to 95 Ω / km.
3. Working capacitance: average 52±2nF/km
4. Insulation resistance: Each core wire is grounded with the other cores, the control cable is greater than 10000MΩ.km, and the HYAT cable is greater than 3000MΩ.km.
5. Far-end crosstalk defense: The average power of the specified combination is greater than 69dB/km at 150kHZ.
Common faults in general control cable lines are mechanical damage, insulation damage, insulation moisture, insulation aging deterioration, overvoltage, cable overheating faults, etc.
Therefore, when the above fault occurs in the control cable, the power supply of the faulty cable should be cut off, the fault point should be searched, the fault should be inspected and analyzed, and then repaired and tested. The cut-off can be resumed after the fault is eliminated.
Control cable installation precautions:
1, the outer wall
Avoid direct sunlight on the wall and human damage. Heat - The temperature of the cable in metal pipes or trunking is high and many polymeric materials will reduce their service life at this temperature.
2, under the eaves
The standard LAN cable can be used only when the cable is not directly exposed to sunlight or high temperature. It is recommended to use the pipe. Ultraviolet (UV)--Do not apply UV-free cables to direct sunlight.
3, in the pipeline (plastic or metal)
For example, in the pipeline, pay attention to the damage of the plastic pipe and the heat conduction of the metal pipe. Mechanical damage (repair cost) - The repair of the cable is very expensive, requiring at least two terminations at each break point.
4, cable trench
Laid directly in the underground cable trench, this environment is the smallest control area. Cable trench installation should be checked regularly for dryness or humidity. Grounding - If the shield of the control cable needs to be grounded, the corresponding standard must be observed.
5, suspended application / overhead cable
Consider the drooping and pressure of the cable. Whether the cable is directly exposed to sunlight.
6, underground pipeline
In order to facilitate future upgrades, cable replacement and isolation from surface pressure and surrounding environment, auxiliary piping is isolated, and auxiliary piping is a better method. But don't expect the pipeline to remain dry forever, which will affect the choice of cable type. Water - The moisture in the LAN twisted pair cable increases the cable's capacitance, which reduces impedance and causes near-end crosstalk.