Cambium PTP 450 series, User Manual

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Cabling and lightning protection PTP 450 User Guide
ptp-450 (July 2014)
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Cabling and lightning protection
This section describes the cabling and lightning protection components of a PTP 450 installation.
PTP and lightning protection
Due to the full metallic connection to the tower or support structure through the BHM antenna, grounding the BHM
and installing a 600SS surge suppressor at the Ethernet cable building ingress is strongly recommended. This
suppresses overvoltages and overcurrents such as those caused by near-miss lightning. BHMSs provide a
grounding lug for grounding to the tower or support structure.
The PTP 450 Series is not designed to survive direct lightning strikes. For this reason the unit should not be
installed as the highest point in a localized area.
Outdoor connections
The term ‘drop cable’ refers to the cable that is used for all connections that terminate outside the building, for
example, connections between the BHM/BHS, surge suppressors (if installed), uGPS receivers (if installed) and the
power supply injector.
The following practices are essential to the reliability and longevity of cabled connections:

Use only shielded cables and connectors to resist interference and corrosion

For vertical runs, provide cable support and strain relief

Include a 2 ft (0.6 m) service loop on each end of the cable to allow for thermal expansion and contraction and
to facilitate terminating the cable again when needed

Include a drip loop to shed water so that most of the water does not reach the connector at the device

Properly crimp all connectors

Use dielectric grease on all connectors to resist corrosion