Xylem SDI-12 RADAR - Manual (Page 11)

Grounding the radar is a simple yet subtle thing to do. Figures on page 10 show the preferred
methods for grounding a radar gauge over a cable. a metal conduit is to be used. if junction
boxes or pull boxes are used, they are to be metal as well. The metal conduit will provide a
conducting path to ground for the radar enclosure and also act as a shield that will conduct away
electrical noise. If a flex conduit is used at the radar enclosure or at the gauge house, this
conduit must be a conducting type of conduit. note: you must also use a conducting
connector for conducting flex conduit. The electrical cable is to have a shield and at least 3
conductors. The wire conductor gauge of 20awg is recommended for most applications, but
you may certainly use 18 or 16 gauge conductors as well.
Installation & Maintenance
9
making Connections
Since the radar can be exposed to the
sun and weather, a cable rated for water
immersion (rain) and sunlight resistance
is required. a polyurethane or similar
sunlight and waterproof rated cable is
recommended. Do not use utility PVC
or other wiring materials which can
become brittle or crack when exposed to
ultraviolet radiation from the sun.
if conduit is used to connect to the radar,
remove and discard the liquid-tight cord
retainer. if metal conduit is used, the
conduit must be grounded. when using
conduit the entry must be sealed with
Caution: remove all power from the unit before making any connections.
Warning: all wiring must be done by qualified individuals in accordance with applicable
codes such as the aNSi/NFPa 70 specifications or the
Canadian electrical Code Part 1.
silicone or other sealant to prevent moisture from entering the radar enclosure via the conduit piping.
The thermal mass of the casting will cause water vapor to internally condense and accumulate with
changes in the weather.
SDi-12 Connections
Liquid Tight Fitting
Grounding Your radar
The following graphic illustrations are the recommended methods for grounding the radar. These
grounding methods will work if the guidelines are strictly followed. it should be mentioned that not
much can protect your site if it suffers a direct lightning strike. However, these general grounding
techniques can certainly help protect the equipment from normal occurrences. it is hoped that this
information will serve as a reference guide to grounding your radar.
Grounding Your radar over Cable