18
WARNING: The
photovoltaic
array generates
hazardous
voltages. A 48
Volt (nominal)
array can
generate nearly
100 volts when
disconnected
from load. A
short circuit or
loose connec-
tion will produce
an arc that can
cause serious
burns. All wiring
must be done by
qualified person-
nel, in compli-
ance with local,
state, and
national electri-
cal codes.
5.3
Solar Array Wiring
2 types of PV module junction systems
TOP Quick-connect system using “MC”
connectors.
BOTTOM Junction box with screw terminals
and conduit holes
The solar array can produce hazardous
voltage even under low light exposure. To
prevent shock hazard while wiring the array,
leave one or more wires disconnected or
cover it with opaque material.
Solar-direct (non-battery) systems use a
variety of array configurations. Some use 12V
(nominal) modules, and some use 24V
modules. Modules are connected in series
for 24 - 36 - 48V and up to 96V (for PS1200
Systems), and sometimes also in parallel to
increase the current.
Refer to the System
Wiring Diagram
for your system, attached at
the end of this manual. Be sure the modules
(panels) match the description on your
System Wiring Diagram.
Solar module connections
The terminals in
the module junction boxes can be confusing.
Refer to the module manufacturer’s instruc-
tions that are packed with the modules. Make
strong connections that will hold for many
years. Most array failures are caused by
loose, corroded, or shorted connections.
Type of wire
Use either electrical conduit or
outdoor UV-resistant wire. The solar array has
a life expectancy beyond twenty years. Don’t
degrade it with inferior materials! Use mini-
mum wire size #12 (4 sq. mm) for the connec-
tions between modules and for short dis-
tances to the controller. Some appropriate
types of wire are: USE, UF, SE and SOOW.
Solar tracker wiring
If you are installing a
solar tracker, pay careful attention to the wire
section that leads from the moving rack down
to the stationary mounting pipe. Use a highly
flexible wiring assembly. Form a drip loop to
shed water and to minimize stress. SEE
TRACKER PHOTO and caption in the PHOTO
GALLERY. Secure the assembly mechanically
at each end so the insulation and the connec-
tions are not stressed by the tracker’s motion.
Swing the tracker fully in each direction, at
various seasonal tilt angles, to verify that the
cable will not rub or restrict the tracking
motion.
MC connectors
Some PV modules have
these quick connectors. If the connector is not
appropriate at some junctions, you can cut the
wire and make a conventional connection.
