LG LG390N3K-V6, Installation Manual

Page: 7 / 18

Parallel Connection
•
The solar modules may be combined in parallel to
produce the desired current output.
•
When modules are combined in parallel, the total
current is equal to the sum of currents from each
module.
•
The voltage of each module connected in parallel
should be the same.
•
When connecting plural strings of modules in parallel e
very series string or solar module must be fused prior t
o combining with other strings.
•
Abide with all applicable federal, state, and local codes
for additional fusing requirements and limitations on the
maximum number of solar modules in parallel.
•
Maximum series fuse rating is refer to “Product
Specifications; page 11”.
•
Parallel configuration is not limited if proper measures
are taken to block the reverse current flow, e.g. fuses f
or the protection of the module and cables from over-
current for prevention of unbalanced string voltage.
•
LG Electronics recommends to take blocking diode
for prevention of unbalanced string voltage.
•
The reverse current flow in the string may be caused by
a module short circuit, incorrect wiring, shadow, etc.
•
Blocking diodes must have :
1) VRRM(Repetitive Peak Reverse Voltage) :
1.5times of maximum system voltage
2) IF (Average Forward Current) :
2 times of Isc (PV module short circuit current)
※
It is selected in consideration of the thermal
characteristics of the diode, and it is recommended
to use a component of 30mA or less for IRRM
(Repetitive Peak Reverse Current, max).
•
A multiplying factor is required for increased output
of the PV modules. Under normal conditions, a PV
module is likely to experience conditions that produce
more current and/or voltage than reported at standard
test conditions. The requirements of the National Elect
rical Code (NEC) in Article 690 shall be followed to ad
dress these increased outputs.
The values of Isc and Voc marked on this PV module
should be multiplied by a factor of 125% when determ
ining component voltage ratings, conductor ampacitie
s, fuse sizes, and size of controls to the PV output.
•
Depending on national directives, additional safety fact
ors might be applicable for over current protection.
7
General Wiring
•
LG Electronics recommends that all wiring be double
insulated with a minimum rating of 90
°
C (194
°
F).
•
All wiring should use a flexible copper (Cu) conductor.
•
The minimum size should be determined by the
applicable codes.
•
LG Electronics recommends a size no smaller than
4mm
2
.
Earth Grounding
•
All work must be conducted in conformance with all
Federal, State, and local codes and standards.
•
Grounding works should be performed by an authoriz
ed installer for the safety and maintenance of the syst
em in accordance with all national, state and local ele
ctrical codes and regulations and standards.
•
Specific information on the solar module dimensions a
nd location of grounding holes is provided in “Product S
pecifications”.
•
One M4 stainless steel bolt, one nut, one spring wash
er, two flat washers, one cup washer, one star washe
r and 12 AWG Cu wires are recommended per mount
ing hole.
•
Where common grounding hardware (nut, bolts, washe
rs) is used to attach a listed grounding device, the attac
hment must be made in conformance with the groundi
ng device manufacturer’s instructions.
•
All hardware should be consist of corrosion resistant
material such as stainless steel.
•
There is an earth hole on the edge of the module f
rame. Using this hole, an earth conductor and the
solar module frame may be recommended to be c
onnected and earthed as the below drawing.
•
All screws and nuts shall be tightened to a torque of
4~5
N∙m.
•
To prevent electric shock and fire, a protective ground must
be done on the frames of solar modules and arrays althoug
h the solar modules from LG meet the conditions of safety
class II. The national directives must be respected.
•
Bonding points to ground should be tight, secure and free fro
m corrosion. (Maintenance is especially important in areas wit
h high levels of salt in the atmosphere, such as coastal areas
and the surrounding seas.)
Module frame
Bolt
Flat washer
Star washer
Cup washer
Grounding wire
Flat washer Spr
ing washer
Nut
Parallel connection for more current
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