Dc Wiring; Dc Wire Sizing And Overcurrent Protection - Magnum Energy MM Series Owner's Manual

• Do not attempt to use a vehicle metal frame in place of the DC
negative connection or DC ground. The inverter requires a reliable
negative and ground return path directly to the battery.
• DC wires and cables should be tied together with wire ties or
electrical tape approximately every 6 inches. This helps improve the
surge capability and reduces the effects of inductance, which im-
proves the inverter waveform and reduces the wear of the inverter's
fi lter capacitors.
• Use only copper wires with a minimum temperature rating of 75° C.
• To ensure the maximum performance from the inverter, all
connections from the battery bank to the inverter should be mini-
mized; the exceptions are the DC overcurrent disconnect in the
positive line and a shunt in the negative line. Any other additional
connection will contribute to additional voltage drops, and these
extra connections points may loosen during use.
• All wiring to the battery terminals should be checked periodically
(once a month) for proper tightness. The torque requirement for the
DC terminals is between 10 to 12 foot-pounds. If you don't have a
torque wrench, ensure all DC terminals are tight and cannot move.
CAUTION: Be aware that overtightening and misthreading
the nuts on the DC terminals can cause the bolts to strip
and snap/break off.

DC Wiring

This section describes the inverter's required DC wire sizes and the
recommended disconnect/overcurrent protection, and how to make
the DC connections to the inverter and the battery bank.

DC Wire Sizing and Overcurrent Protection

It is important to use the correct DC wire to achieve maximum ef-
fi ciency from the system and reduce fi re hazards associated with
overheating. See Table 1 to select the minimum DC wire size needed
based on your inverter model. If the distance from the inverter to the
battery bank is greater than 3 feet, use Table 2 to help determine
the minimum recommended cable sizes for longer distances. Always
keep your wire runs as short as practical to help prevent low voltage
shutdowns, and keep the DC breaker from nuisance tripping (or open
fuses) because of increased current draw. Undersized cables can also
lower the inverter's peak output voltage as well as reduce its ability to
surge heavy loads.
© 2010 Magnum Energy, Inc.
2.0 Installation
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