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©
2010 Magnum Energy, Inc
.
Installation
2.6 Grounding
Inverters
The inverter/charger should always be connected to a permanent, grounded wiring system. An
inverter system that is properly grounded will limit the risk of electrical shock, reduce radio frequency
noise from the inverter and minimize excessive surge voltages induced by lightning. This is done
by ensuring there is a well-de
fi
ned, very low-resistance path from the electrical system to the
grounding system. This low-resistance path helps stabilize the electrical system voltage with respect
to ground and carries fault currents directly to ground if the electrical system malfunctions.
To understand how the conductors in the electrical circuit will be connected to the system ground,
the following terms should be understood:
Grounded Conductor
(GC)
: The wire/cable in the electrical system that normally carries current (usually
the AC neutral and/or the DC negative); and is intentionally connected or “bonded” to the ground
system. This wire or the ends of this wire should be colored white or gray.
Equipment Grounding Conductor
(EGC)
: A wire/cable that does not normally carry current and is used
to connect the exposed metal parts of equipment that might be accidentally energized to the grounding
electrode system or the grounded conductor. This wire or the ends of this wire should be green or green
with a yellow stripe; or this wire can be bare copper.
Grounding Electrode Conductor
(GEC)
: The wire/cable that does not normally carry current and connects
the grounded conductor and/or the equipment grounding conductor to the grounding electrode at the
service equipment.
Grounding Electrode
(GE)
: A ground rod or conducting element that establishes an electrical connection
to the earth.
System bonding jumper (
SBJ
) The connection between the grounded circuit conductor in the electrical
system and the equipment grounding conductor at a separately derived system.
The RD Series inverter/charger uses both AC and DC power; however, the AC electrical system is
isolated from the DC electrical system by an internal transformer. Although this inverter/charger
has two electrical systems, each electrical system
must
be properly grounded and connected to
a common “earth” reference; refer to Figure 2-15.
For proper grounding, each electrical system must connect all exposed metal parts of equipment
(via Equipment Grounding Conductors - EGC) and one of the current-carrying conductors (Grounded
Conductor - GC) together at a common point (Ground Busbar - GBB), usually by a System Bonding
Jumper (SBJ) in an electrical service disconnect panel. The common point of each electrical system
is then connected (via Grounding Electrode Conductor - GEC) to the common ground reference,
such as a ground rod (Grounding Electrode - GE). This connection to earth should only be made
at one point in each electrical system; otherwise, parallel paths will exist for the currents to
fl
ow.
These parallel current paths would represent a safety hazard and are not allowed in installations
wired per the NEC/CEC.
•
•
•
•
•
A C
D C S e rvice
P a n e l
A C S e rvice
P a n e l
D C E lec tric al S y s tem
A C E lec tric al S y s tem
N eutral
Positive
N egative
D C
G rounding
S y s tem
N e g a tive
S B J
GC
GE
GE C -A C
E GC
AC Ground
D C Ground
S B J
E GC
GC
N e u tra l
H ot
GE C -D C
GE
GE
GB B
GB B
Grounding Electrode
(AC and D C sides shared)
Grounding Electrode
(D C side dedicated)
Grounding Electrode
(AC side dedicated )
or
or
R D S e rie s In ve rte r/C h a rg e r
Figure 2-15, Grounding System for RD Series
