Student Practical PV Install #2
29 April 2006
Location: Strath Creek, Victoria.
Supervisor: Glen Morris (BCSE Accred. F1441)
Installing 6 x 100W RWE Schott Solar module array (24V) on a UniRac pole top mount
View from pole top mount (foreground with white bucket on top) looking north east before PV array installed.
Graham and Ralph running conduit for the PV array wiring (13.5mm sq cable).
Ralph clipping 25mm corrugated conduit to wall with half saddle clamps.
Tom securing PV array surge protection earth stake. Note how the stake is secured against the pole using a 20mm half saddle that has been squeezed to fit tightly around stake.
Tom with his partially completed PV array junction box. Note that all conduit is secured against mechanical damage with half saddles.
Partially completed wiring of PV array junction box. Consists of positive and negative termination bars, earth bar and 6 x 6A circuit breakers (to provide both overload protection and isolation at the array itself). MOV surge protectors in plastic bag yet to be installed. The MOV's are tinned with the new RoHS compliant (lead free) solder and thus require higher temperature irons (227°C) and lead free solder.
NB. Max. short circuit current = 3.2A therefore according to AS5033 the protection for each string needs to be between 1.25 x Isc and 2 x Isc = 4 - 6.4A (we used 6A breakers).
Post visit completion
4 May 2006
A few days later the array was errected (6 x 100W Schott Solar modules on a UniRac pole top mount).
Detail of UniRac single point mounting system. Tilt and azimith adjustments are very simple once the frame is in position. Can be assembled on the ground then lifted onto pole.
Completed PV Array Junction Box. Note the six blue MOV's used as surge protection on the solar positive of each string.
Wide spacing of modules lessens wind loading in this windy site, though the frame and module array are rated for 200km/h wind speeds. Owner wishes to add additional guy wires to wooden posts behind - just to be sure it won't blow away.