An integrated lead suspension is formed from a laminate of three materials in a variety of configurations having from three to five layers. A base sealing member on the roof base is provided for covering the through hole and an exit is provided in the base sealing member through which the electrical wire extends into the space between the solar cell module and the roof base at a portion of the base sealing member other than a portion just over the through hole of the base sealing member. A first copy of the test signal is transmitted via a reference path of known characteristics and with minimal impairments.