What is the difference between service rated and non service rated?

The National Electric Code (NEC) requires a way for disconnecting the electrical service where it enters a building. This main circuit breaker prevents the building from demanding too much current from the utility creating a dangerous conditions. This circuit breaker may be in a separate panel or part of a service entrance rated transfer switch. There isn’t any over-current protection within a non-service entrance rated transfer switch. Therefore, when you install this type of transfer switch, it will be after the service disconnect panel. Service entrance switches will have a service disconnect at the utility side. This installation requires less components, making it ideal for new construction, which can be more cost effective.