DAVIS Gro/Energy/Health Installation - Manual (Page 19)

Typical Installations
Standard System Installation Manual Page 19
Field System with Wired DC Power
This system configuration has the same characteristics and advantages as those
of the AC-powered system described in “Field System with AC Power” on
page 18. In this case AC power is not wired to the site. Rather, the power
adapter is plugged into an available circuit in a sheltered location, and the
(nominal) 12-Volt DC output is supplied to the station with a two-wire cable
(twisted-pair is preferred, but not required). The two wire cable is connected to
the power Y-Cable using a single Surge Protector, Terminal Box, or splice con-
nectors. The Surge Protector may be housed in a Small Surge Protector Shelter
as shown below, or it may be attached to the back panel of the shelter. The table
below lists some recommended maximum distances, which are determined by
the wire gauge used.
F IELD S YSTEM WITH W IRED DC P OWER
M AXIMUM C ABLE R UN T YPE OF C ABLE
460 feet (140 m) 24 AWG Pair (.20 mm 2 )
600 feet (180 m) 22 AWG Pair (.32 mm
2
)
1000 feet (300 m) 18 AWG Pair (.82 mm
2
)