Wiring Considerations
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7.1 Power Wiring
1. Power wiring—rectifier input, bypass input, UPS output and battery cables—must be run in
individual, separate conduits or cable trays. Refer to the Outline and Bussing Details drawings
(Figures 14, 15, 19, 21, 23, 25, 43 and 44) for locations of the various power connections within
the UPS and ancillary equipment. In particular, note the location of the rectifier input power
connections.
2. Observe local, state and national electrical codes. Verify utility power and its overcurrent
protection rating will accommodate the UPS input rating, including battery recharging.
3. A safety ground wire must be run from the building ground to a ground point in the UPS Module
Cabinets, ancillary equipment and the Power-Tie Cabinet (if applicable). See 6.0 - Configuring
Your Neutral and Ground Connections. The grounding conductor shall comply with the
following conditions of installation:
a. An insulated grounding conductor must be sized in accordance with the NEC and local codes.
It must be green (with or without one or more yellow stripes) and be installed as part of the
branch circuit that supplies the unit or system.
b. The grounding conductor described above is to be grounded to earth at the service equipment
or, if supplied by a separately derived system, at the supply transformer or motor-generator
set in accordance with the instructions in 6.0 - Configuring Your Neutral and Ground
Connections.
c. The attachment-plug receptacles in the vicinity of the unit or system are all to be of a
grounding type, and the grounding conductors serving these receptacles are to be connected to
earth ground at the service equipment.
4. Observe clockwise phase rotation of all power wiring. Phase A leads Phase B leads Phase C.
A qualified electrician should check the phase rotation.
5. AC power cables must be rated to meet NEC requirements for voltage drop at the maximum rated
system current. DC power cables from the UPS to the battery terminals and return must be sized
for less than 2 volts total loop drop at the maximum rated system current.
6. If site equipment includes a backup generator and automatic transfer switch(es), consult the
manufacturers of those devices for information on sizing and interfacing to the UPS system.
7. Removable access plates are available for power wiring. Refer to the Outline Drawings for your
particular model (Figures 14, 19, 21, 23, 25, 43 and 44).
!
CAUTION
Power and control wiring must be separated!
!
CAUTION
After cutting holes in the access plates, be certain that no foreign matter (metal shavings,
sawdust, insulation or wire fragments, etc.) remains inside the UPS. Likewise be certain to
block any “extra” holes in the plates through which foreign matter could later enter the UPS.
