Magnum Energy Magnum Panel (MP Series) - Manual (Page 51)

Page 44 © 2011 Magnum Energy, Inc.
3.0 Installation
3.7 DC Wiring
This section describes the DC wiring from inside the MP enclosure to the inverter, and from the
MP enclosure to the battery bank.
Info: If installing optional DC breakers, see Section A6 in Appendix A.
3.7.1 DC Wiring Guidelines
WARNING: During normal operation the terminals, busbars, and electrical components
inside the MP enclosure may be energized - DO NOT TOUCH. Disconnect all power
sources before removing the cover.
WARNING: Even though the DC voltage/battery bank is considered “low voltage”,
signifi cant hazards are present because of the high current available, particularly if the
battery system has a short circuit.
CAUTION: Before wiring the DC cables, review the safety information at the beginning
of this manual and the following information to ensure a safe and long-lived system.
CAUTION: If you are using fi ne-stranded DC cables, the crimp or compression lug
used must be specifi cally marked or labeled for use with fi ne-stranded conductors.
Failure to use the proper terminal may cause the connection to heat-up, and it may
eventually fail or become a fi re hazard.
CAUTION: DO NOT connect the battery cables to the inverter until all wiring is
complete, and the correct DC voltage and polarity have been verifi ed.
• When the inverter is installed in a Photovoltaic System, the NEC requires that the DC circuit
conductors and overcurrent devices to the inverter be sized to carry not less than 125% of
the inverter’s maximum current rating.
• The DC positive and negative cables from the battery bank should be tied together with wire
ties or electrical tape approximately every six inches. 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.
• Crimped and sealed copper compression lugs with a 3/8” hole should be used to connect the
battery cables to the DC Disconnect Breaker and the DC Shunt busbar inside the MP enclosure.
• The battery bank voltage MUST match the DC voltage required by the inverter (i.e., 24-volt
battery bank for a 24-volt inverter), or the inverter may be damaged.
• The DC cables must be of a type listed for use in conduit (i.e., THHN, RHW or THW).
• To ensure the maximum performance from the inverter, all connections from the battery
bank to the inverter through the MP enclosure should be minimized, the exception is the DC
circuit breaker in the positive line and the DC shunt in the negative line. Any other additional
connection will contribute to additional voltage drops and may loosen during use.
• All wiring to the inverter and battery terminals should be checked periodically (once a month)
for proper tightness. Refer to the torque requirements in Tables 3-1 to 3-3.
• After making the battery connections and ensuring they are properly tightened, cover the
outside of the connection with petroleum jelly or an antioxidant grease/spray. Do not put
jelly/anti-corrosion grease between the terminal and the battery cable.
• Ensure the color code for the DC cables/wires are correct: RED for positive (+); WHITE for
negative (-); and GREEN, GREEN with YELLOW stripe, or bare for DC equipment grounds.