| Grounding and surge protection requirements | |||
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CAUTION
Equipment warranty can be voided
The equipment warranty can be voided if the guidelines detailed in the National Electric Code (NFPA 70), Standard for Installation of Lightning Protection System (NFPA 780, latest edition) and Alcatel-Lucent 401-200-115 are not followed.
The UMTS Macrocell base station must be grounded with an integrated (multi-point) grounding system. The equipment is susceptible to lightning surges due to its association with towers and antennas. Therefore, it is imperative that the cell site be properly grounded and that a low impedance path to earth is provided. The grounding conductors must be as straight and short as possible. No sharp bends or loops are permitted in grounding conductors.
The RF and GPS antenna coaxial cables are also susceptible to lightning surges and must be protected*.
A surge protection device must be installed between each antenna coaxial cable and jumper cable, at the point where the antenna cables enter the building*. They can be obtained from Alcatel-Lucent (KS24577 L-5A (1900 and 2100 MHz) and KS24577 L-4A (850 MHz) for RF, and KS24577 L-3A for GPS if used), or a Alcatel-Lucent approved equivalent.
The surge protectors must be bonded to a nearby ground bus bar that is connected directly to the grounding electrode system at two points.
The antenna cable shield must be bonded at the top of the tower next to the antenna, and at the bottom of the vertical run. If the tower is too high, the antenna cable shield must be bonded at approximately 30-meter (100-ft.) intervals. The tower or metallic support for the antenna must also be bonded to the grounding electrode system.
The following diagram shows a typical antenna grounding and surge protector installation.
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