User's Guide

Chapter 4: System planning
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Chapter 4: System planning
Site planning
This section describes factors to be considered when planning the proposed link end sites, including
grounding, lightning protection and equipment location for the ODU and PSU.
Grounding and lightning protection
Structures, equipment and people must be protected against power surges (typically caused by lightning) by conducting the surge
current to ground via a separate preferential solid path. The actual degree of protection required depends on local conditions
and applicable local regulations. To adequately protect a PTP installation, both ground bonding and transient voltage surge
suppression are required.
Full details of lightning protection methods and requirements can be found in the International Standards IEC 61024-1 and IEC
61312-1, the U.S. National Electric Code ANSI/NFPA No. 70-1984 or section 54 of the Canadian Electric Code.
Lightning protection zones
Use the rolling sphere method (Rolling sphere method to determine the lightning protection zones) to determine where it is
safe to mount equipment. An imaginary sphere, typically 50 meters in radius, is rolled over the structure. Where the sphere rests
against the ground and a strike termination device (such as a finial or ground bar), all the space under the sphere is in the zone
of protection (Zone B). Similarly, where the sphere rests on two finials, the space under the sphere is in the zone of protection.
Figure 26 : Rolling sphere method to determine the lightning protection zones
Warning
Electro- magnetic discharge (lightning) damage is not covered under warranty. The recommendations in this
guide, when followed correctly, give the user the best protection from the harmful effects of EMD.
However,
100% protection is neither implied nor possible.
Note
International and national standards take precedence over the requirements in this guide.