Power Supply And Wiring Preparation Of The Ups System - Eaton 93PR Series Installation And Operation Manual

3.2.2.

Power supply and wiring preparation of the UPS system

For maintenance bypass installation, dual-feed input protected by an upstream circuit
breaker or single-feed input protected by two upstream circuit breakers shall be adopted.
Wherein, one is for UPS/rectifier input breaker (if installed), and the other is for the
maintenance bypass input. It's forbidden to merely employ single-feed and single-breaker
protection for UPS/rectifier input and maintenance bypass. If the UPS adopts single feeder
line and a bypass input breaker is mounted on the maintenance bypass, maintenance
bypass single-feed input is allowed, and power can be supplied to the UPS and bypass
simultaneously.
As for the actual configuration of external wiring, please refer to the local or national electrical
specifications:
• To facilitate future expansion, power line and external overcurrent protection switch shall be
selected for derating under full load.
• Materials and operations for external wiring requirements shall be supplied and performed by
designated personnel.
• External wiring shall adopt the copper wire capable of withstanding 105℃. Please see
relevant information in
• If the operation temperature of conductor is above 40℃, it's necessary to use the wire that is
thicker or capable of withstanding higher temperatures.
• The wiring specifications are defined by copper wire at 105℃.
4-wire system:
• The input adopts three live wires and an N wire, in addition to a grounding conductor
(protective grounding conductor). To ensure the normal operation of the equipment, the
phase lines must be grounded in a symmetric manner (from Y-type/star-type power supply).
• Support loads with N wire.
• For UPS systems configured with a 4-Pole ATS or generator, make sure the switching of the
upstream ATS will not cause disconnection of N wire, or the input N wire disconnection is
recovered before low battery voltage alert:
• When the N wire is disconnected, all phase lines shall be disconnected as well.
The wire with appropriate size shall be used to facilitate future upgrade.
23
CAUTION
Table 3-3 . The wire size depends on the circuit breaker.
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