7
Figure 3.1
Module Ground Position
Junction Box
Label
Backside
The ground holes
are on the backside of
the module frame.
Ground Location
(holes for bolt and nut)
Array Wiring
The term “array” is used to describe
the assembly of several modules on
a support structure with associated
wiring.
Use copper wire which insulation is
sunlight resistant and can withstand
the maximum possible system open
circuit voltage.
Interconnection of modules must be
performed in a professional fashion.
Wires should be secured and only
reasonable slack should be allowed.
Check local codes for requirements.
Earth Ground Wiring
A module with exposed conductive
parts
is
considered
to
be
in
compliance with UL 1703 only when
it
is
electrically
grounded
in
accordance with the instructions
presented
below
and
the
requirements
of
the
National
Electrical Code.
All modules should be grounded. All
structures or metallic components in
direct contact with the modules or
electric wires should be properly
grounded too. To avoid the hazards
of electric shock or fire, modules
should be grounded by the frame
only at the locations marked in this
manual (see grounding methods
below).
The array frame shall be grounded in
accordance with NEC Article 250
(USA) or the CEC in Canada.
Bonding shall be by a positive means,
such as clamping, riveting, bolted or
screwed connectors, or welding,
soldering or brazing. If the bonding
means depends upon screw threads
two or more screws or two full
threads of a single screw must
engage the metal.
Great care should be exercised to
ensure that corrosion caused by the
grounding means be avoided.
Corrosion can increase the resistance
of the grounding connection on the
module, or can even cause the
grounding connection to fail entirely.
Corrosion can be caused by the
effects of weather, humidity, dirt
and so on. It can also be caused
when two dissimilar metals are in
contact (galvanic reaction).
The
module
frame
material
is
aluminum/magnesium alloy.
All fasteners (nuts, bolts, washers,
screws, etc.) must be stainless steel
unless otherwise specified.
Length of bolt should not be more
than 0.78’’ (20 mm) in order to
avoid contacting the back-sheet of
the module.
Acceptable
grounding
wire
is
following.
Ilsco Corp. GBL-4DBT 10-14AWG-
Solid,
4-6,
8,
10-14AWG-Strand
Burndy L L C CL501TN 14AWG-Solid,
14-4AWG-Strand
Tyco Electronics Corp. 1954381-
1/1954381-2 10-12AWG Solid
Each ledge on the module frame has
two holes for bolts (0.205’‘diameter
(5.2 mm)). These ground holes are
marked with a “G” or "ground mark"
adjacent to their location on the
frame rail (see Figure 3.1).
Ground wires must be connected to
the module’s metal frame at one of
these locations.
Lay-in lugs or grounding clips can be
used
to
ground
Panasonic
PV
modules.
Both
methods
are
explained below, please choose one.
Grounding Locations (or grounding
holes)
Using bolt and nut
(see Figures 3.3 and 3.5)
If using this method, use one of the
holes with diameter of 0.205’‘ (5.2
mm)
The bolt and nut size should be
No.8 (0.164’‘diameter (4.16
mm)),
or
No.10
(0.190’‘diameter (4.83 mm))
or M5 (0.197’‘diameter (5.0
mm)).
Star washers must be used to
make contact through the
anodization of the module
frame.
In this case, the screw threads are
not providing the electrical ground
contact.
Recommended
torque
value
in
tightening bolt and nut is 2.3 N.m
(20in-lb).
Grounding Methods
Where
common
grounding
hardware (nuts, bolts, star washers,
spilt-ring lock washers, flat washers
and the like) is used to attach a
listed
grounding/bonding
device,
the attachment must be made in
conformance with the grounding
device manufacturer's instructions.
Common hardware items such as
nuts,
bolts,
star
washers,
lock
