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UPS WITH BYPASS ELECTRICAL INSTALLATION
Eaton 9170
+
UPS (3–18 kVA) User's Guide S 164201393 Rev E www.eaton.com/powerquality
22
See Table 2 for recommended conductor sizes to wire the input circuit
breakers.
Table 2. Recommended Wire Sizes
Input Circuit Breaker Size 75°C Copper Wire Size Conductor Screw Torque
25A 5.3 mm
2
(10 AWG) 4.0 Nm (35 lb in)
40A 8.4 mm
2
(8 AWG) 4.5 Nm (40 lb in)
60A 21.2 mm
2
(4 AWG) 5.1 Nm (45 lb in)
80A 26.7 mm
2
(3 AWG) 6.6 Nm (50 lb in)
100A 33.6 mm
2
(2 AWG) 6.6 Nm (50 lb in)
125A 42.1 mm
2
(1 AWG) 6.6 Nm (50 lb in)
FOR U.S. INSTALLATIONS, READ THIS IMPORTANT NOTE!
This table lists the mm
2
and AWG wire size for each circuit breaker size shown on the
wiring diagrams. The minimum recommended circuit breaker sizes for each model and
voltage application are listed on the wiring diagrams.
Conductor sizes shall be no smaller than the 75°C wire size based on the ampacities
given in Table 310–16 of the National Electrical Code, ANSI/NFPA 70-1999, and
article 220. All circuit conductors, including the neutral conductor, must be the same
size (ampacity) wire. Code may require a larger AWG size than shown in this table
because of temperature, number of conductors in the conduit, or long service runs.
Follow local code requirements.
Bypass Switches
Bypass switches are available in two types: Make-Before-Break (MBB)
and Break-Before-Make (BBM).
An MBB switch makes a new connection before it breaks the original
connection. For example, if you turn an MBB switch from UPS to LINE,
the bypass switch connects the load to AC input power before
disconnecting the load from UPS output power. (As noted in Figure 38
on page 57, MBB switches may not be used in certain system
configurations.)
A BBM switch breaks the original connection before it makes a new
one. If you turn a BBM switch from UPS to LINE, the switch
disconnects the load from UPS output power before connecting the load
to AC input power.
The bypass switch has four positions as described in Table 3.