Figure 8, Neutral-To-Ground Switching With External Ac - Trace Engineering LEGEND II Manual

For this system to work, the AC output neutral of the inverter must be isolated from the ground of the
system (usually the green wire). When in the inverter mode, the neutral ground switching relay will
automatically connect (bond) the output neutral to ground, and when in charger/pass-through mode,
the ground and neutrals will be bonded to one another at the AC source (generator or shore power).
The diagram below graphically describes the ground switching system in the inverter for a unit
connected to an external AC source (generator, grid etc.) and passing the AC power through the
inverter to the AC sub-panel.
Relay RY-A connects the AC input and
AC output HOT sides together to allow
power to pass through the inverter when
AC is present at the inverter inputs.
RY-A
Inverter
out
AC
GROUND
HOT
NEUTRAL
GROUND

Figure 8, Neutral-to-Ground Switching with External AC

WK

RY-B
HOT IN
NEUTRAL IN
Neutral-to-Ground "BOND" is provided by the
external AC source for entire AC system
Relay RY-B connects the NEUTRAL (IN)
from the external AC source and NEUTRAL
(OUT) of the loads together when AC is
applied to the inverter.
HOT OUT
NEUTRAL OUT
AC Sub-panel
(Inverter loads)
N
E
U
GND
The
neutral
conductor
shall be
insulated
from the
equipment
grounding
conductors
or
enclosures