Magnum Energy Series Stacking Cable Kit (ME-SSI) - Manual (Page 18)

©
2010 Magnum Energy, Inc.
Installation
13
Neutral to Safety Ground Bonding
Electrical safety standards for wiring mobile (RV, boat, or truck)
and AE (houses, cabin, or offi ce) installations require: an AC
source such as the utility feed in your home, an inverter or
a generator, and the neutral conductor tied to ground. These
standards also require that the AC neutral be connected to safety
ground (often called a “bond”) in only one place at any time (often
called a “bond”). If more than one bond is established, currents
can circulate between neutral and ground and cause ground-
loop currents. These “ground-loops” can trip GFCIs and cause an
electric shock hazard.
The fundamental difference between using an inverter in a mobile
installation as opposed to an AE installation is how the neutral is
grounded in the AC system. There may be multiple AC sources in
mobile installations, which means there is the potential of having
multiple neutral to ground connections. Therefore, if you are
using an inverter as one of your AC sources along with another
AC source (i.e., utility power or generator), you must ensure that
the inverter does not also connect the neutral to ground while
the other AC source is actively powering the inverter loads. In AE
installations, the main service panel provides the neutral to ground
bond for the entire electrical system – not in the inverter.
The MS4024 inverter provides an internal relay that connects the
neutral to ground while inverting and opens this neutral-to-ground
connection automatically when connected to an active AC source,
such as utility power or a generator.
WARNING: Each MS4024 inverter in a series stacked
confi guration provides a neutral-to-ground connection,
creating two “bonds” at the same time. Depending on the
installation, either one or both of the neutral-to-ground
connections inside the inverter must be disconnected to
prevent multiple neutral to ground connections.
In a mobile installation, the neutral-to-ground connection in one
of the MS4024 inverters in a series stacked confi guration must be
disconnected; while leaving the neutral-to-ground connection in
place in the other MS4024 inverter to allow the automatic neutral-
to-ground switching to continue for the series stacked pair.
In an AE installation, the neutral-to-ground connection in both of
the MS4024 inverters must be disconnected, because the neutral-
to-ground connection is provided in the main AC panel.
WARNING: Any neutral-to-ground bond downstream
from the inverter must be removed to prevent multiple
bonds. If there is an inverter sub-panel — separate from
a “main” electrical panel — it should have a removable
wire that allows the neutral bus to be unbonded from
the ground bus.