6
Figure 3.1
Module Ground Position
Junction Box
Label
Backside
The ground holes
are on the backside of the
module frame.
Ground Location
(larger holes for bolt and nut)
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
larger 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 larger
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 washers and the
like have not been evaluated for electrical
conductivity or for use as grounding devices
and should be used only for maintaining
mechanical connections and holding electrical
grounding devices in the proper position for
electrical conductivity. Such devices, where
supplied with the module and evaluated
through the requirements in UL 1703, may
be used for grounding connections in
accordance with the instructions provided
with the module.
Wire connection using cup washers
(see Figures
3.2)
The use of cup washers is to prevent wire
from slipping out from under the screw
head (and/or the flat washer).
Make sure that the cup washer is placed
between the wire and the module frame.
Choose an adequate size for the cup
washer and the flat washer so that the
wire is fully clamped between them.
Note: Cup washers are also called terminal
cup washers.
The cup washers should be stainless steel,
or a cup washer made of brass may be
used only if a large flat washer made of
stainless steel is inserted between the
module frame and the cup washer.
Choose the adequate size for the large flat
washer (between the module frame and
the cup washer) so that the cup washer
doesn’t contact the module frame and is
fixed stably to the module frame.
Method- Use a bolt and nut (see Figures 3.1 and
3.2)
If using this method, use one of the larger
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 for this method.
In this case, the screw threads are not
providing the electrical ground contact.
Using a lay-in lug with bolt and nut
If using this method, please follow
instructions in previous section regarding
