Chapter 3: System planning
Site planning
Page 3-22
Figure 17 Rolling sphere method to determine the lightning protection zones
Zone A: In this zone a direct lightning strike is possible. Do not mount equipment in this zone.
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 equipment in this zone.
Warning
Never mount equipment in Zone A. Mounting in Zone A may put equipment,
structures and life at risk.
Site grounding system
Confirm that the site has a correctly installed grounding system on a common ground ring with
access points for grounding PTP 550 equipment.
If the outdoor equipment is to be installed on the roof of a high building (
Figure 20
), confirm
that the following additional requirements are met:
•
A grounding conductor is installed around the roof perimeter to form the main roof
perimeter lightning protection ring.
•
Air terminals are installed along the length of the main roof perimeter lightning protection
ring, typically every 6.1m (20ft).
•
The main roof perimeter lightning protection ring contains at least two down conductors
connected to the grounding electrode system. The down conductors should be physically
separated from one another, as far as practical.
