User Manual

Understanding surge protection and grounding
IP-RN 8000 Installation & Commissioning Guide 33
Understanding the backhaul switch
The backhaul switch is pre-installed. The backhaul switch is field-replaceable. Replacing the backhaul
switch is service disrupting.
The backhaul switch is inside the cabinet and is not visible. It performs two important functions:
• Secondary surge protection
The IP-RN 8000 is protected from system transients on the backhaul caused by lightning and power
cross conditions.
• T1/E1 backhauls are switched and connected with the BIO/SC that is currently active.
For example, if your backhaul is a single T1 and you have a redundant IP-RN 8000 (with two Digital
Module Kits), you only need to provision a single T1 and wire it to the backhaul punch block. If the
redundant Digital Module Kit become active, the backhaul switch switches the T1 from the primary to
the redundant Digital Module Kit.
Ethernets are not switched. If you are deploying an Ethernet backhaul and you have a redundant
IP-RN 8000 (with two Digital Module Kits), you must provision and connect two Ethernets to the
backhaul punch block. One Ethernet is used as the backhaul by the primary Digital Module Kit and the
other Ethernet is used by the redundant Digital Module Kit.
Understanding surge protection and grounding
The IP-RN 8000 has multiple connections for attachment to the site’s grounding infrastructure. The
IP-RN 8000 has a secondary surge protection system for additional protection against lightning strikes
beyond the protection provided by a required primary external surge suppression system. A primary surge
protection system must be designed by qualified personnel for each site and must be installed accordingly to
prevent equipment damage and to minimize danger to nearby persons during lightning strikes.
Understanding the secondary surge protection system
The secondary surge protection system consists of surge suppressors for each antenna and surge suppressors
for the T1/E1 backhaul links that are electrically connected to the lighting ground coil. (For information
about the lightning ground coil, see Figure 3
.) The lightning ground coil must be connected to an external
earth ground infrastructure.
The secondary surge protection system is designed to supplement a required external primary surge
protection system. Both must be in place to protect equipment and persons against lightning strikes traveling
down the cell tower along the RF and GPS antennas to the IP-RN 8000. Any surge that passes the required
external primary surge protection system is expected to take the following path to the earth ground
infrastructure:
• From the RF and GPS antennas through the surge suppressors onto the surge protection bar
• From the surge protection bar to the directly connected lead to the lightening ground coil
• From the lightning ground coil to the required external earth ground infrastructure
WARNING
Installation of a primary surge protection system and proper
grounding of the IP-RN 8000 according to all relevant codes and
requirements is necessary to avoid potential damage to the
equipment and to minimize danger persons near the equipment
during surges. Lightning protection design must be performed by
qualified personnel for each IP-RN 8000 installation.