11
Figure 7C: Installation Wiring Diagram for B610 6 & 10 kVA Models
with MBB External Bypass Switch (1, L2, N) and External Isolation Transformer
60 Hz 208 or 480 VAC Source with Input Step-Up or Step-Down Isolation Transformer
240 UPS Input - 120/240 UPS Output
BUILDING GROUNDING
ELECTRODE OR
PROTECTIVE EARTH
SYSTEM
AC LINE INPUT
AC TO
UPS INPUT
AC FROM
UPS OUTPUT
AC TO LOADS
Note 2
Note 6
Note 10
Note 7
Note 5
Note 8
Note 3
TO
LOADS
Note 4
Note 4
Note 4
N
N
L1
L1
L2
L2
Note 1
9 10 11 11 12 12
15 16
13
5 6 7 8
1 2 3 4
N
N
L1
L1
L1
L2
L2
L2
N
L1
L2
Note 2
Note 11
Note 12
Note 11
Note 8
!
L1 L2
X1 X2 X3 X4
Note 9
Note 6
Note 4
NOTE 1: The customer must provide input overcurrent
protection as stated in NEC Section 240-21 or local codes.
Size the protection device according to local code requirements.
NOTE 2: The UPS bypass switch must be installed within
sight of the UPS. To properly install, complete the voltage
and phase check procedure on pages 14 and 15. The wires
coming from the side of the switch must be connected
to the ES2 plug on the Best Relay (AS400) card. See
Section 704 for wiring instructions.
NOTE 3: The customer must provide and install this ground
(earth) connection per NEC Sections 250-20, 250-30, 250-62
and 250-64, or local code requirements. This grounding electrode
conductor must be at least #8 AWG (8.36 mm
2
) per NEC
table 250-66. If the UPS input circuit conductors are larger
than #8 AWG (8.36 mm
2
), Best Power requires the grounding
electrode conductor to be the same size (ampacity) as the
largest UPS input circuit conductor. See NEC Section 110-3(b).
Conduit is not considered an acceptable grounding electrode
conductor. Best Power recommends that you do not route
the grounding electrode conductor through metallic conduit.
This conductor may require protection from physical damage
according to local code requirements.
NOTE 4: All AC circuit conductors, including the neutral and
equipment grounding conductors, must be the same size
(ampacity), have the same rating (75° C copper wire), and
be sized according to the input circuit breaker. The UPS input
and output conductors must be run through separate conduits.
NOTE 5: The customer must provide output overcurrent protection.
See NEC Section 240-21 or local requirements. See Figure 8 for
maximum output overcurrent protection device ratings.
NOTE 6: See Figure 8 for proper output wiring termination and neutral-
to-ground (neutral-to-earth) connection.
NOTE 7: For maximum protection against electrical noise, use isolated
ground receptacles. See NEC Section 250-146(d).
NOTE 8: See Section 302 for installation and service clearances
before installing the UPS. Use flexible conduit on the UPS or the
external battery cabinet if either must be moved.
NOTE 9: External UPS battery cabinets are optional. See Section
305 for installation instructions.
NOTE 10: For 208 VAC, use a step-up transformer. For 480 VAC,
use a step-down transformer. Use an isolation transformer with a
120/240 grounded center-tapped neutral output.
Do not use a
buck/boost transformer.
NOTE 11: UPS output circuits shall be installed in dedicated
conduit systems and not shared with other electrical circuits.
NOTE 12: The load fuse or circuit breaker should be sized to match
the load current requirements.
