If the Building Inspector determines that an electrical installation or alteration as proposed in an application complies with this chapter and all other applicable statutes and regulations, said official shall issue to the applicant a written electrical permit authorizing the proposed work. Permits shall become invalid unless the work on the site authorized by such permit is commenced within 180 days after its issuance, or if the work authorized on the site by such permit is suspended or abandoned for a period of 180 days after the time the work is commenced. In addition, all work authorized by such permit must be completed within two years.