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Grounding and lightning protection
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.
Motorola recommends that PTP 800 installation is contracted to a professional
installer.
Standards
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.
CAUTION
Lightning Protection Zones
The 'rolling sphere method' is used to determine where it is safe to mount antennas
or ODUs. 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 considered
to be in the zone of protection (Zone B). Similarly, where the sphere rests on two
finials, the space under the sphere is considered to be in the zone of protection.
Assess locations on masts, towers and buildings to determine if the location is in
Zone A or Zone B:
x
Zone A: In this zone a direct lightning strike is possible. Do not mount the
antenna or ODU in this zone.
x
Zone B: In this zone, direct EMD (lightning) effects are still possible, but
mounting in this zone significantly reduces the possibility of a direct strike.
Mount the antenna and ODU in this zone.
WARNING
2-6
EMD (Lightning) damage is not covered under standard warranty. The
recommendations in this user manual, when implemented correctly, give
the user the best protection from the harmful effects of EMD. However
100% protection is neither implied nor possible.
Never mount the antenna or ODU in Zone A. Mounting in Zone A
may put equipment, structures and life at risk.
Chapter 2 Planning considerations
phn-1478_005v000
Apr 2010
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