User Guide

PMP 450 Planning Guide Grounding and lightning protection
pmp-0047 (December 2012)
2-33
General protection requirements
To adequately protect a PMP 450 installation, both ground bonding and transient voltage surge suppression are
required.
Basic requirements
The following basic protection requirements must be implemented:
• The equipment must be in ‘Zone B’ (see Lightning protection zones on page 2-32).
• The AP must be grounded to the supporting structure.
• A surge suppression unit (600SS) must be installed close to the SM.
• The distance between the SM and 600SS should be kept to a minimum.
• The drop cable length between the SM and 600SS must be less than 600 mm.
• An surge suppression unit (200SS) must be installed within 600 mm (24 in) of the point at which the power
cable enters the building or equipment room.
• The drop cable must be grounded at the building entry point.
• The drop cable must not be laid alongside a lightning air terminal.
• All grounding cables must be a minimum size of 10 mm
2
csa (8AWG), preferably 16 mm
2
csa (6AWG), or 25
mm
2
csa (4AWG).
Grounding cable requirements
When routing, fastening and connecting grounding cables, the following requirements must be implemented:
• Grounding conductors must be run as short, straight, and smoothly as possible, with the fewest possible number
of bends and curves.
• Grounding cables must not be installed with drip loops.
• All bends must have a minimum radius of 203 mm (8 in) and a minimum angle of 90° (Figure 17). A diagonal
run is preferable to a bend, even though it does not follow the contour or run parallel to the supporting
structure.
• All bends, curves and connections must be routed towards the grounding electrode system, ground rod, or
ground bar.
• Grounding conductors must be securely fastened.
• Braided grounding conductors must not be used.
• Approved bonding techniques must be used for the connection of dissimilar metals.