Cambium PTP 450 series, Руководство пользователя

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PTP 450 User Guide Grounding and lightning protection
2-72
ptp-450 (July 2014)
Assess locations on masts, towers and buildings to determine if the location is in Zone A or Zone B:

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.
Never mount equipment in Zone A. Mounting in Zone A may put equipment, structures and life at risk.
General protection requirements
To adequately protect a PTP 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 2-71 ).

The BHM must be grounded to the supporting structure.

A surge suppression unit (600SS) must be installed close to the BHS.

The distance between the BHS and 600SS should be kept to a minimum.

The drop cable length between the BHS and 600SS must be less than 600 mm.

A surge suppression unit (600SS) 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 18 ). 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.