Alpha Technologies Cordex CXPS-D 48-2500_5000A - Manual (Page 44)

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6.3 Connecting the Frame and Reference Grounds
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NOTE: This power system is suitable for installation as part of a Common Bonding Network (CBN) and is intend-
ed to be used in a DC-C configuration (common DC return).
A true single point ground system means that everything is referenced to a single point that is tied to the external
earth ground system. In reality each component and external source is effectively bonded to a single point, which
is then effectively bonded to the facility or site external ground system.
6.3.1 Connecting the power plant battery return reference lead
1. Connect the isolated power system battery return bus (BRB) of the primary bay to the building master ground
bus (MGB) or floor ground bus (FGB) in larger buildings (Figure 30). This acts as a system reference and
a low impedance ground path for surges, transients, noise, etc. The MGB or FGB should have a direct low
impedance path to the building grounding system.
2. Size the cable between the power system and the MGB or FGB so that there is sufficient ampacity to clear
the largest fuse or breaker on the power system, excluding the battery protection fuse or circuit breaker—750
MCM is recommended. This is the minimum requirement for these high capacity plants. Other factors,
including length of cable and special grounding requirements of the load, must be factored in. The insulated
cable should be equipped with two-hole crimp type lugs and should not have any tight bends or kinks.
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