What Is The Maximum Permitted Rating On Branch Circuits: Explained In 20 Words

What is the maximum ampere rating allowed for a branch circuit breaker? According to Section 210.18 of the electrical code, the branch-circuit rating is determined by the maximum permissible ampere rating or setting of the overcurrent protective device. In this case, the maximum rating for the branch circuit breaker is 20 amperes, as specified by the code. This regulation was last updated on June 16, 2022.

The rating range for branch circuits, excluding individual ones, typically falls within the range of 15, 20, 30, 40, and 50 amperes. If conductors with a higher ampacity are employed for specific reasons, the ampere rating or setting of the designated overcurrent device will dictate the overall circuit rating. This means that the circuit’s capacity is contingent on the ampere rating of the protective device in use.

What is the maximum allowable branch circuit protection for a power supply? The maximum allowable rating for fuses used solely for branch circuit protection should not exceed 175% of the rated-load current of the hermetic motor-compressor or the branch circuit selection current, whichever value is larger. This means that when choosing fuses to protect the power supply’s branch circuits, they should be sized based on this 175% limit, using the larger of the two available current values: the rated-load current of the hermetic motor-compressor or the branch circuit selection current. This helps ensure safe and effective protection for the power supply system.