Disclosed is an epoxy resin composition for printed circuit board, which includes an epoxy resin; a composite curing agent, including an amino-triazine-novolac resin and dicyandiamide mixed in a certain proportion; a curing accelerator; and an optional inorganic filler. Furthermore, each of said upper cage portions defines with the bottom cage portion a respective compartment having an inner cavity for receiving an electronic module, and a subdivision of said bottom cage portion provides for a bottom wall of said compartment. When a plurality of solar panels are arranged on a roof in courses with an upper course partially overlapping a lower course, the junction boxes of roofing panels in the upper course are disposed in the cutouts of roofing panels of the lower course.