Plumbing, heating, air conditioning contractor and repair services; electrical contractor services; retrofit and replacement of existing systems and appliances, namely, piping, ductwork, wiring; repair, retrofit and installation of piping, ductwork, wiring and appliances, equipment, fixtures, motors and parts thereof; installation of new plumbing systems, heating systems, air conditioning systems, electrical systems and control systems, namely, piping, ductwork, wiring and appliances, equipment, fixtures, motors and parts thereof