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MNL107-900-000D
2.3 INSTALLATION
CONSIDERATIONS
Figure 2-3 illustrates typical wiring to and from the AC/DC 1200. When the load is running from
the inverter (not-by-passed) the output circuit is completely floating with respect to the AC input,
DC input and earth connection. This arrangement provides the user with flexibility in regards to
the output circuit reference point. When in the bypass mode, the inverter is disabled and the AC
input is routed directly from the AC input terminal to the output terminals (refer to Figure 1-1 in
section 1). This will place the output circuit at the same reference as the AC
line.
In
North
America the neutral terminal is defined as the “grounded conductor” and is bonded
to
the
earth connection at the service entrance. This is defined in the Nation Electrical Code (NEC)
section 250 regarding bonding and protective (a.k.a. safety) earth connections.
The NEC considers AC sources that are Isolated from the AC supply as “separately derived
sources”. Stand alone back-up generators, some UPSs, and battery powered inverters fall into
this category. If this equipment is to be installed in a building or vehicle that must meet the NEC,
then grounding of the output circuit will be required. This can be accomplished by the connection
suggested in the figure 2-4 below. For units with a terminal block output option this is easy to add.
Units with NEMA plug output may require adding an external outlet box to make this connection.
If specified at time of order, units can be modified by Behlman to provide this connection. A
connection could be added from AC output low terminal to earth, however this would violate NEC
bonding rules when the unit is in the bypass mode. If this concept is not understood consultation
with a licensed electrician is highly recommended.
FIGURE 2-4
