This requirement applies only to single-family residential buildings. The main electrical service panel shall have a minimum busbar rating of 200 amps and shall have a reserved space to allow for the installation of a double-pole circuit breaker. The reserved circuit breaker space shall be on the opposite (load) end from the input feeder or main circuit location. The reserved circuit breaker space shall be permanently marked as “For Future Solar Electric”. These items are required to simplify the possible future installation of a solar electric system.