Overview; Lightning Protection Zones - Motorola PTP 600 Series User Manual

11.1 Overview

The idea of lightning protection is to protect structures, equipment and people against
lightning by conducting the lightning current to ground via a separate preferential solid path
and by reducing the electromagnetic field.
The following should be treated as a guide only, the actual degree of lightning protection
required depends on local conditions and weather patterns and applicable local regulations.
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.

11.1.1 Lightning Protection Zones

The installation of the ODU can be classified into two different lightning protection zones.
Zone A — In this zone a direct lighting strike is possible.
Zone B — In this zone a direct lightning strike is unusual, but the un-attenuated
electromagnetic field is still present.
The zones are determined using the 'rolling sphere method', an imaginary sphere, typically 50
meter in radius is rolled over the structure. All structure points that contact the sphere, (Zone
A) indicate the zone where a direct strike is possible. Similarly points that do not contact the
sphere indicate a zone (zone B) where a direct strike is less likely.
The following diagrams (Figure 93 & Figure 94) show this zoning pictorially:
Equipment mounted in Zone A should be capable of carrying the full lightning current.
Mounting of the ODU in Zone A is not recommended. Mounting in Zone A should only be
carried out observing the rules governing installations in Zone A
structures, equipment and life at risk.
Equipment mounted in Zone B should be grounded using grounding wire of at least 10 AWG.
This grounding wire should be connected to a grounding rod or the building grounding system
before entry in to building.
The 600 Series bridge ODU grounding point can be found on the bottom of the unit. The 600
Series bridge is supplied with an appropriate grounding lug for attachment to the ODU.
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Local regulations may also require the fitting of the 8 AWG ground wire referred below.
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Failure to do so may put