1. Heat - the temperature of the cable in the metal pipe or trunk is very high, and many aggregate materials will fall in service life at this temperature.
2, water - the moisture in the LAN twisted pair cable will add the capacitance of the cable, which reduces the impedance and causes near-end crosstalk
3, mechanical damage (correction costs) - the correction of the cable is very expensive, at least two terminations at each discontinuity.
4. Grounding - If the shield of the cable needs to be grounded, it is necessary to adhere to the corresponding specifications.
5, the total length of the route (not only refers to the floor) - the use of outdoor-grade LAN twisted pair cable between the buildings, the total length should be limited to within 90 meters. Regarding a 100Mps or 1000Mbps network, the laying interval cannot exceed this limit. If the interval between laying is between 100 and 300 meters, the fiber optic cable should be selected.