INSTALLATION - PV MODULES
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The following procedure should be adhered to whilst wiring module strings to prevent the risk of electric
shock or inadvertent short circuiting of live cables whilst wiring the Rooftop DC Isolator:
1.
Two extension leads per string should be constructed using the DC extension cable provided in the BOS
Kit. One should be short to connect from the first module in the string to the DC isolator. The other
should be sufficiently long to plug the end module in the string to the DC isolator (see the example
schematic below).
2.
Ensure the Rooftop DC Isolator is in the OFF position, strip 12 mm of insulation from the end of each
extension lead and connect the two extension leads to the Rooftop DC Isolator terminals. The Rooftop
DC Isolator should be wired in a consistent manner. Refer to “DC Isolator Wiring” on page 35.
3.
Connect the first module positive (+) cable plug to the Rooftop DC Isolator extension cable negative (-)
plug.
4.
Connect each module’s negative (-) cable to the following module’s positive (+) cable as modules are
being installed until the halfway point is reached i.e. fourth module in an eight module string.
5.
Install and connect the remaining modules, but do not make the halfway connection, i.e. in an eight
module string do not connect the fourth module negative (-) cable to the fifth module positive (+) cable
(refer to wiring diagram below). These two cables will be connected at the end of this procedure.
6.
Connect the last module’s negative (-) cable to the Rooftop DC Isolator extension cable positive (+)
plug.
7.
Complete the circuit by connecting the two string halves together by connecting the positive (+) and
negative (-) cables of the two modules left previously disconnected in step 5.
Note:
Modules may be connected in a different order provided that all modules in a string are connected in
series.
Note:
The Rooftop DC Isolator should still be in the OFF position at the completion of this stage of the
installation. It should not be turned ON until the correct stage of commissioning. Refer to “Solar Isolation
Device(s) Test – Rooftop DC Isolator(s)” on page 49.
EARTHING
All modules and rails must be earthed. Refer to “Earthing Arrangements – All Systems” on page 18. Earthing
connections must be made by a suitably qualified person according to the relevant standards outlined on
page 19. It is also recommended that a reliable lightning protection system be installed.
Stainless steel serrated washers must be used so the rail anodising is pierced, providing good electrical
continuity. Stainless steel nuts, bolts and washers must be used and all ferrous metal in conductive
connections should be specially treated to prevent corrosion (i.e. by spray painting or coating with a
galvanising paint). Refer also to “Earthing Arrangements – All Systems” on page 18.
Earthing plates
To earth modules and rails, use earthing plates supplied when mounting modules. Install earthing plates in
accordance with the following instructions. When installed correctly, earthing plates will provide earth bond
continuity between rails and modules whilst allowing removal of a module without affecting the earthing
integrity of other components in the system. The rails must then be earthed by connecting a suitably sized
earth wire. Refer to “Earthing Arrangements – All Systems” on page 18.
