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MX28B200/400 –48 VDC User’s Manual (990-9133) Page 9
WARNING: The MX28B DC power plant is supplied from a
nominal 220VAC, 60 Hz source. Keep the AC input enclosure
in place when the system is operational or energized.
3.4. Battery Connections
WARNING: Hazardous energy levels are present on bare
conductors in the -48VDC distribution connection area of the
plant. Accidental shorting of distribution conductors can cause
arcing and high currents that can cause serious burns or other
physical harm. It is recommended that:
• Any jewelry, rings or watches be removed while working
on this equipment.
• Handles of all wrenches, screwdrivers, cutters and pliers
be insulated.
• Shafts of screwdrivers be wrapped in electrical tape or
otherwise insulated
Planning the Battery installation
The battery cable(s) should be sized sufficiently large to limit the voltage drop from the
MX28B DC power plant to the battery during charging per system design requirements.
The cable(s) must also carry the full load current during battery operation. If assistance
is required to determine the necessary cables for the application, contact your sales
representative or APC.
An external fuse or circuit breaker (various options are available from APC) is required in
the negative line (located at the battery end) to protect the cables from the battery to the
MX28B DC power plant. The power plant can monitor auxiliary contacts from this
breaker.
Connecting the Cables
WARNING: Make certain that the battery polarity is correct
when making connections to the Model MX28B DC power
plant. Incorrect connection could cause severe equipment
damage.
The battery cable connections are located at the top rear of the unit as shown in Figure
3.4-1. The battery positive (return bus) and battery negative (-48V bus) buses each
provide two sets of threaded 3/8”-16 holes on one-inch centers for connecting two-hole
battery cable lugs. Connect the battery cables as applicable using 3/8-16 bolts (not
provided) and tighten them with a torque wrench to 200 in-lbs (23 N-m).