Type A electrical services are used to power lighting circuits only. All circuits are controlled by a lighting contactor and photo control. All circuits are automatically switched on during the night and off during the day. Line voltage for Type A services may be 120/240V or 240/480V.

Type A services use individual feed-through branch circuit breakers mounted to a back plate in the cabinet. Typically the maximum number of circuits in a Type A service is 4 or 5.