Notices Receiver Card
OEM7 Installation and Operation User Manual v4
14
Lightning Protection Installation and Grounding Procedure
What is the hazard?
A lightning strike into the ground causes an increase in the earth's potential which results in a
high voltage potential between the center conductor and shield of the coaxial cable. This high
voltage develops because the voltage surge induced onto the center conductor lags in time
behind the voltage surge induced onto the shield.
Hazard Impact
A lightning strike causes the ground potential in the area to rise to dangerous levels resulting in
harm to personnel or destruction of electronic equipment in an unprotected environment. It also
conducts a portion of the strike energy down the inner conductor of the coaxial cable to the con-
nected equipment.
Only qualified personnel, such as electricians mandated by the governing body in the
country of installation, may install lightning protection devices.
Actions to Mitigate Lightning Hazards
1. Do not install antennas or antenna coaxial cables outside the building during a lightning
storm.
2. It is not possible to avoid over voltages caused by lightning, but a lightning protection device
may be used to shunt a large portion of the transient energy to the building ground, reducing
the over voltage condition as quickly as possible.
3. Primary lightning protection must be provided by the operator/customer according to local
building codes as part of the extra building installation.
4. To ensure compliance with clause 7 "Connection to Cable Distribution Systems" of EN 60950-
1, Safety for Information Technology Equipment, a secondary lightning protection device
must be used for in-building equipment installations with external antennas. The following
device has been approved by NovAtel Inc.:
Polyphaser - Surge Arrestor DGXZ+36NFNF-A
If this device is not chosen as the primary lightning protection device, the device chosen
must meet the following requirements:
l
UL listed, or equivalent, in country of installation (for example, TUV, VDE and so on) for
lightning surge protection
l
The primary device must be capable of limiting an incoming surge to 10 kV
5. The shield of the coaxial cable entering the building should be connected at a grounding plate
at the building's entrance. The lightning protection devices should have their chassis groun-
ded to the same ground near to the building's entrance.
6. The primary and secondary lightning protections should be as close to the building's entrance
as possible. Where feasible, mount onto the grounding plate itself (refer to the figure
below).
