Chapter 6 Battery 51
Liebert APM 90 Integrated Modular UPS User Manual
6.10
Reference Current And Connection Of BCB
Table 6-3 provides recommended BCB rated current and connection cable CSA.
Table 6-3
Reference table for selection of BCB rated current and connection cable CSA (recommended)
UPS rating
（
kW*
）
Item
Unit
18
36
54
72
90
Max. battery discharge (both
positive and negative) current
at full load
A 45 90 135 180 225
36-block
battery
Reference rated current of BCB
A
160
160
160
250
320
Connection cable CSA
A
42
84
126
168
210
38-block
battery
Max. battery discharge (both
positive and negative) current
at full load
A 160 160 160 250 250
Reference rated current of BCB
A
40
80
120
160
200
40-block
battery
Connection
cable
CSA
A 160 160 160 250 250
1. If the external battery is configured to have separate wiring of positive terminal and negative terminal (that is, four wires
will be led out from the battery side), for the UPS, due to the limitation of the rated current, it is recommended to use a 4P
DC MCCB (DC rated voltage of the breaker meeting 1-pole 250Vdc, 2-pole 500Vdc, 3-pole 750Vdc, rated breaking
capacity limit being 35kA) or two 2P DC MCCBs (DC rated voltage of single breaker meeting 1-pole 250Vdc, 2-pole
500Vdc, rated breaking capacity limit being 35kA). Connections between the battery, BCB and UPS are shown in
Figure 6-3.
2. If the external battery is configured to use CT wiring (that is, three wires will be led out from the battery side), it is
recommended to use a 4P DC MCCB, with DC rated voltage of the breaker meeting 1-pole 250Vdc, 2-pole 500Vdc, 3-pole
750Vdc, and rated breaking capacity limit being 35kA. If the battery cell number ranges from 36 to 40, refer to Figure 6-4
for the connections between the battery, BCB and UPS.
3. The max. battery neutral cable current can reach half of the current of the battery positive and negative cables. When
sizing the neutral cable, refer to this cable, and take the neutral cable currents as half of the currents listed in the table.
4*. When the UPS output power factor is 0.9, the battery current is the same as that of power factor to 1. For example, the
battery current of 100kVA/90kW is equal to 90kVA/90kW.
+
N
N
-
+
N
-
UP
S
U
P
S
N
N
N
Figure 6-3
Connections between battery, BCB and UPS (4 wires at battery side)
