Magnum Energy MMS Series - Manual (Page 20)

© 2014 Magnum Energy, Inc. 14
Installation
• DC wires and cables should be tied together with wire ties or
electrical tape approximately every 6 inches (15.2 cm). This
helps improve the surge capability and reduces the effects of
inductance, which improves the inverter waveform and reduces
wear on the inverter’s fi lter capacitors.
• Use only copper wires with a minimum temperature rating of
75°C (167°F).
• To ensure maximum performance from the inverter, all connec-
tions from the battery bank to the inverter should be minimized
(Exception: the DC overcurrent disconnect in the positive line).
2.2 DC Wiring
This section describes the MMS Series 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.
2.2.1 DC Wire Sizing
It is important to use the correct DC wire to achieve maximum ef-
fi ciency from the system and to reduce fi re hazards associated with
overheating. Use 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 (91.4 cm), 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 to 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.
Info: The DC wires must be color coded with colored
tape or heat shrink tubing; RED for positive (+), BLACK
for negative (-), and GREEN for DC ground.
The DC wires must have soldered and crimped lugs, crimped copper
compression lugs, or aluminum mechanical lugs. Soldered connec-
tions alone are not acceptable for this application.
If the inverter is expected to operate at a distance greater than 3 feet
(91.4 cm) from the battery bank, the DC wire size will need to be
increased to overcome the increase in resistance—which affects the
performance of the inverter. Continue to use the overcurrent device
and DC ground wire previously determined from Table 1 and then,
refer to Table 2 to determine the minimum DC wire size you need
for various distances based on your inverter model.
2.2.2 DC Overcurrent Protection
For safety and to comply with NEC (National Electrical Code) electrical
code regulations, you must install a DC overcurrent protection device
in the positive DC cable line to protect your DC cables. This DC
overcurrent device can be a fuse or circuit-breaker, but must be DC