10
BUILDING GROUNDING
ELECTRODE OR
PROTECTIVE EARTH
SYSTEM
AC LINE INPUT
AC TO
UPS INPUT
AC FROM
UPS OUTPUT
AC TO LOADS
Note 2
Note 10
Note 4
Note 4
Note 7
Note 5
Note 3
Note 4
TO
LOADS
Note 4
N
L2
L1
L1
L2
Note 1
9 10 11 11 12 12
15 14 13
5 6 7 8
1 2 3 4
N
N
N
L1
L1
L1
L1
L2
L2
L2
L2
Note 2
!
L1 L2
X1 X2 X3 X4
Note 9
Note 6
Note 8
Note 10
Note 10
Note 11
Figure 7B: Installation Wiring Diagram for B610 6 & 10 kVA Models
with External MBB Bypass Switch (L1, L2, N)
• 208 Input, 120/240 Output
• 208 Input, 208 or 240 Output
• 208 Input, 120/208 Output
• 60 Hz 220 Input, 220 Output (Mexico)
• 120 or 240 Input, 120/240 Output
NOTE 1: The customer must provide input overcurrent pro-
tection 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: UPS output circuits shall be installed in dedicated
conduit systems and not shared with other electrical circuits.
NOTE 11: The load fuse or circuit breaker should be sized to match
the load current requirements.
