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©
2017 Sensata Technologies
Installation
2.4 DC
Wiring
This section describes the inverter’s required DC wire sizes, the recommended
disconnect/overcurrent protection, and how to make the DC connections to
the inverter and the battery bank.
WARNING:
Even though DC voltage can be regarded as “low
voltage”, signi
fi
cant hazards may be present, particularly from short
circuits of the battery system.
CAUTION:
The inverter is NOT reverse polarity protected—if the
negative and positive battery voltage is connected to the inverter
backwards, the inverter will likely be damaged. Use a voltmeter to
verify the correct polarity BEFORE connecting the DC wires.
CAUTION:
DO NOT connect the battery cables to the inverter until
all wiring is complete and the correct DC voltage and polarity have
been veri
fi
ed.
Refer to Figure 2-7 when connecting the DC wires to the battery, and to
Figure 2-8 when connecting to the inverter. Also, consider the following
requirements to ensure maximum performance:
The inverter’s DC positive and negative cables from the battery bank should
be tied together with wire ties/straps or electrical tape approximately every
6 inches (15.3 cm). This helps improve the surge capability and reduces the
effects of inductance, which improves the inverter waveform and reduces
the wear of the inverter’s
fi
lter capacitors. Keeping the battery cables close
together also reduces the chance of radio frequency interference.
Be aware that over-tightening or misthreading the nuts on the DC terminals
can cause the bolts to strip and snap/break off.
Make sure cables have a smooth bend radius and do not become kinked.
Follow existing wire runs where possible.
Crimped and sealed copper ring terminal lugs with at least a 6 mm (1/4”)
bolt hole to connect the DC wires to the inverter’s DC terminals.
The battery bank voltage MUST be between 10.5 – 15.5 (10.5 – 15.75 for
the CSW412) for the inverter to operate. If the voltage exceeds 16.0V, the
inverter may be damaged.
To ensure the maximum performance from the inverter, all connections from
the battery bank to the inverter should be minimized. The exceptions are the
DC fuse and disconnect, or the DC circuit breaker—required at the battery to
protect the DC wiring—in the positive line. Any other additional connection
will contribute to additional voltage drops, and these extra connection points
may loosen during use.
A brief spark or arc may occur when connecting the battery cables to the
inverter DC terminals; this is normal and due to the inverter’s internal
capacitors being charged.
Before routing the wiring, color code the DC cables/wires with colored tape
or heat shrink tubing: RED for positive (+); WHITE for negative (–); and
GREEN (or bare copper) for DC ground, to avoid polarity problems.
A cable should be connected directly from the inverter negative terminal
to the battery negative connection; this ensures the inverter has a reliable
return path directly to the battery. Do not use the chassis in place of the
battery negative connection to the inverter.
