Short circuit protection of low voltage motor branch circuits, by HRC II-C fuses

It is pointed out that HRCII-C fuses meeting CSA Specification C22.2 no.106-M 1985 and complying with the requirements for type gG fuses of IEC269-1986 provide proven backup protection to IEC rated contactors and motor starters, ensuring Type 2 coordination and enabling their motor starting capabilities to be fully utilized. HRCII-C fuses provide lower power losses than the HRCI-J fuses for the same application, which is a significant factor in modern compact motor control centers. It is further noted that the pending revision of C22.2 no.106 will rectify a weakness in the 1985 edition by recognizing the fact that the HRCII-C fuses can meet let through limits significantly less than those indicated in that edition.<>