37 Construction services, construction planning and consulting services, construction supervision services; installation, maintenance and repair of ammonia and industrial refrigeration systems; commercial and industrial refrigeration repair services; installation, maintenance and repair of electrical systems; mechanical and electrical construction services, and maintenance services to public, private, institutional and commercial buildings; mechanical construction services, namely, providing mechanical, plumbing and HVAC systems; installation and maintenance for others of fire protection and life safety systems, namely, fire alarms; building, repair, and maintenance service for fire equipment and fire protection systems; electrical construction services, in the nature of, sizing, equipment selection for incoming main service, electrical power distribution, motor control; repair and maintenance for systems, namely, lighting systems, general electrical power systems, electrical construction and maintenance systems, commercial and industrial security systems and energy-saving systems