Grounding Electrodes/Ground Rods; Bonding The Grounding System - Xantrex7 UX - REV A Owner's Manual

3.0 Installation
Pre-Installation Planning (continued)
System Grounding (continued)

Grounding Electrodes/Ground Rods

NOTE: Be sure to consult your local
and national electrical codes
to confirm grounding and
bonding requirements for
your specific system.
WARNING: NEVER USE A
GAS PIPE, GAS LINE, OR
WATER PIPE FOR
GROUNDING PURPOSES!

Bonding the Grounding System

NOTE: The ground and neutral
must be bonded at one
place, and only one place,
in the system.
If the generator is the main
source of power, (i.e., no
utility grid power) then the
neutral and ground
connections are bonded at
the main AC distribution
panel.
If the utility grid is the main
source of power, then the
bond should be at the utility
AC distribution panel.
If there is no utility or
generator in the system,
then the ground/neutral
bond should be in the
inverter AC distribution
panel.
©2002 Xantrex Technology Inc. All Rights Reserved.
P/N 975-0026-01-01 Rev A 06/2002
The purpose of the grounding electrode (often called a ground rod) is to "bleed"
off any electrical charge that may accumulate in the electrical system and to
provide a path for "induced electromagnetic energy" or lightning to be
dissipated. The size for the conductor to the grounding electrode or grounding
system is usually based on the size of the largest conductor in the system. Most
systems use a copper-plated rod as the grounding electrode. The rod should be
5/8 inch (16 mm) round by 6 feet (2 meters) long and driven into the earth. It is
also common to use copper wire placed in the concrete foundation of the
building as a grounding system. Either method may be acceptable, but the local
code will prevail. Connection to the ground electrode should be done with
special clamps located above ground where they can be periodically inspected.
Many large systems use multiple ground rods. The most common example is
providing a direct path from the solar array to earth near the location of the solar
array. Most electrical codes want to see the multiple ground rods connected by a
separate wire with its own set of clamps. If this is done, it is a good idea to make
the connection with a bare wire located outside of the conduit (if used) in a
trench. The run of buried wire may be a better grounding electrode than the
ground rods. Well casings and water pipes can also be used as grounding
electrodes. Under no circumstance should a gas pipe or line be used. Consult
local codes and the NEC for more information.
Bonding means connecting one of the current-carrying conductors (usually the
AC neutral and DC negative) to the grounding system. When the other
ungrounded conductor (the hot or positive) touches the grounding system,
current will flow through it to the point of connection to the grounded conductor
and back to the source. This will cause the overcurrent protection to stop the
flow of current, protecting the system. This point of connection between the
grounding system (ground rod), the current carrying grounded conductor (AC
neutral and DC negative), and the equipment grounding conductor (green ground
wire, equipment ground) is called a "bond".
Bonding is usually located in the overcurrent protection device enclosures (both
AC and DC). Although it can be done at the inverter, codes do not generally allow
it since the inverter is considered a "serviceable" item that may be removed from
the system. In residential systems, it is located at the utility panel, after the
power has gone through the kilowatt-hour meter of the utility (if present).
Bonding must be done at only one point in an electrical system. Inherently,
Xantrex systems have two separate electric systems – a DC system and an AC
system. This means that two bonding points will occur in all inverter
applications. The bonding point will also be connected to the equipment
(chassis) grounding conductors. It is common to have two separate conductors
connect the ground electrode and the two bonding points. Each conductor
should use a separate clamp.
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