standards and guidelines for communication sites - Radio And ...

CHAPTER
7
SURGE PROTECTIVE DEVICES 7
7.1 INTRODUCTION
This chapter includes the following topics:
• “Technologies Available” on page 7-4
• “Suppression Mode Definitions” on page 7-4
• “AC Power SPD Requirements” on page 7-5
• “Telephone/Control/Data Network Circuit SPDs” on page 7-34
• “RF Components Protection” on page 7-36
• “GPS Receiver Protection” on page 7-44
• “Tower Lighting Protection” on page 7-45
• “Battery Powered Protection” on page 7-47
• “AC Power Line SPD Test Certification Requirements” on page 7-47
The installation of Transient Voltage Surge Suppression (TVSS) devices is a requirement for all
communication sites and is essential for all facilities where communication- related electronics
and electrical equipment is in use. Surges and transient power anomalies are potentially
destructive electrical disturbances, the most damaging being over-voltage occurrences and short
duration over-voltage events. Sometimes referred to as “spikes”, high-energy transient power
anomalies can arise from inductive load switching or other events within the power system or
capacitive and inductive coupling from environmental events such as nearby lightning activity.
Environmental and inductive power anomalies are wideband occurrences with a frequency
range from close to DC to well into the RF high frequency spectrum. It is critical that each pointof-entry
(AC, telephone, LAN, signal/control and RF) into the equipment area be protected
against these anomalies. This protection is essential to reduce the risk of personal injury,
physical equipment damage, and loss of operations (equipment down time). Although lightning
can cause the most visible damage, it is not the predominant cause of transient voltages.
Transient voltage sources include, but are not limited to the following:
• Power company switching
• Generator transfer
• Shared commercial feeders with poor line regulation
• Load switching
• Fault currents
• HVAC units
• Heating elements
• Power tools
• Electric motors
• Fluorescent lights
68P81089E50-B 9/1/05 7-1