Installation Guide Manual

3.7.3 Battery over current protection and wire sizing
• Please read the safety precautions at the front of this guide carefully, and thoroughly review the
battery manufacturers installation and maintenance manual before connecting the batteries to the
UPS.
• If the UPS system has been purchased with an accompanying battery cabinet, that cabinet should
have an integral battery circuit breaker.
If the UPS has been purchased without a battery cabinet or remote rack mounted batteries are to
be used then DC over current protection must be provided by others.
• Choose an appropriate DC fuse or circuit breaker using the current data in the chart below.
• Minimum battery cable requirement is based on the current data below.
The AC values below are current ratings per phase.
These maximum and nominal ratings should be considered when choosing the appropriate AC
over current protection device.
NEC (National Electric Code) Section 210-20 a rules must be applied.
DC current rating is the nominal battery discharge current which the UPS allows.
(See Fig. 3.7.1-1 and 3.7.1.2)
AC Input Rectifier
AC Input
AC Input
Bypass
DC Input
F1 F3
UPS rating
Nom. Max.
F2
Nom. Max.
F4
SG Series 50 kVA
65.5 A 81 A 60.1 A 65.5 A 81 A 100 A
SG Series 80 kVA
104.7 A 125 A 96.2 A 104.7 A 125 A 159 A
Size of Branch Circuit Over current Protection - All Models: - "CAUTION - To reduce the risk of fire,
only connect UPS to a circuit provided with (See below) maximum amperes branch circuit over
current protection in accordance with the NEC (National Electric Code), NSI / NFPA 70
AC Input Rectifier AC Input Bypass AC Input DC Input
UPS rating
F1 F2 F3 F4
SG Series 50 kVA
110 80 110 110
SG Series 80 kVA
175 125 175 200
WIRING
Wire sizing according to
NEC Section 210-20 (a) Table 310-16
Use 75°C (167°F) copper wire
Wiring requirements:
AC INPUT RECTIFIER: 3-Phase, 3 wire plus Ground
AC INPUT BYPASS: 3-Phase, 4 wire plus Ground
AC OUTPUT: 3-Phase, 4 wire plus Ground
DC INPUT: 2 wire (positive and negative) plus Ground
Maximum cable diameter that terminals can accept
Refer to torque specifications table for torque requirements
UPS rating Rectifier Input Bypass Input DC Input AC Output GND
SG Series 50 kVA
4/0 AWG 4/0 AWG 4/0 AWG 4/0 AWG 4/0 AWG
SG Series 80 kVA
4/0 AWG 4/0 AWG 4/0 AWG 4/0 AWG 4/0 AWG
Modifications reserved Page 20/38
OPM_SGS_ISG_50K_80K_0US_V040.doc Installation Guide SG Series 50 & 80 kVA