Hi Jim, the first wire, coming from the output of the ABG-25 should be 6mm AUTO ( 4.5mm2 ) but all other connections can be made using 5mm AUTO ( 2.5mm2 ).
NOTE, if you use 5mm2 for the daisy chain connections, you can use YELLOW crimp terminals and 2 x 5mm2 wire will fit into a YELLOW crimp terminal.
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