series wiring
parallel wiring
If you select or assemble your own wiring for
a photovoltaic solar power system, please
observe the following points:
}
Use only wiring material that is specifi-
cally intended to be used in photovoltaic
solar power systems.
}
At extreme low temperatures the cable
should be handled with more than usual
care.
}
Select wiring material with insulation that
is UV-resistant and weatherproof. It should
have a rated voltage of at least 600 V.
}
The cross-sectional area of the (stranded)
conductor depends on the maximum
short-circuit current and the overall length
of the wiring.
}
If you use multi-conductor cable, the
insulation of the individual conductors
must be resistant to damage resulting from
movement
Typically, conductors with a cross-sectional
area of at least 2.5 mm
2
are used, although
4 mm
2
is recommended. Shell Solar recom-
mends using wiring specially designed for
solar power systems. Ask your dealer to
recommend manufacturers that can provide
cables with connectors made to meet your
requirements.
Use suitable connectors
If you select or assemble connectors for a pho-
tovoltaic solar power system, please observe
the following points:
}
Use only connectors that are specifically
intended to be used in photovoltaic solar
power systems.
}
Use the tools recommended or prescribed
by the connector manufacturer for assem-
bling connectors.
}
Do not unplug a connector while the circuit
is under load. It is OK to unplug a connec-
tor while the circuit is ‘live’.
}
Use protective caps to guard loose con-
nectors against the effects of weather.
Special connectors for solar power system
are commercially available - ask your dealer.
Installing solar-power wiring
Correctly installed wiring assures reliable
long-term operation of the photovoltaic solar
power system. Please observe the following:
}
Keep cable length as short as possible to
reduce efficiency / voltage drop.
}
If you connect several modules together,
secure the wiring to the support frame.
}
Where possible, use suitable fasteners to
restrict the range of motion of loose sec-
tions of wiring.
}
Avoid running wiring over sharp edges.
Comparison of series and parallel wiring
For applications with a
high operating volt-
age
, several photovoltaic modules can be
connected in series:
V
total
= V
1
+V
2
+V
n
I
total
= I
1
= I
2
= I
n
A photovoltaic system with a high open-cir-
cuit voltage is suitable for use with a battery
storage system having an operating voltage
of 48 V or more.
}
The maximum open-circuit
voltage of the system must not
be greater than the specified
maximum system voltage for
the module.
}
There is an increased risk of short circuits
and arcing with high DC voltages. Use
adequately insulated wiring and connectors
that are approved for use at the maximum
open-circuit voltage.
For applications with
a high current con-
sumption
, several photovoltaic modules can
be connected in parallel:
I
total
= I
1
+I
2
+I
n
V
total
= V
1
= V
2
= V
n
A parallel wiring is suitable for use in sys-
tems containing low-voltage loads with high
power consumption, or for optimising the
charging process with high-capacity battery
storage systems.
}
The wiring and connec-
tors can become overheated
at high currents. Use wiring
with suitable cross-sectional
areas and connectors that are approved
for use at the maximum short-circuit cur-
rent. Observe the manufacturer’s instruc-
tions and local electrical code.
}
It is recommended to use additional
junction boxes when connecting several
modules in parallel. Modules with conduit
ready (CR) ProCharger™ junction boxes
can be directly connected in parallel.
Use suitable solar-power wiring
Modules supplied with pre-assembled cables
can easily be connected to other modules
or matching electrical components, such as
charge regulators or inverters, using plug
connectors.
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