The statement that MCCB, ICCBs, and LVPCBs all have the same 1.5 cycle typical fault clearing time is true.

• A. True
• B. False
• C. Not specified
• D. Unknown

Answer: (B)

Fault-clearing time is governed by how the protective device detects a fault and activates the mechanism, which varies by device design and protection scheme. Molded Case Circuit Breakers, Insulated/Integrated Case variants, and Low-Voltage protective breakers each use different trip curves and mechanisms (thermal for overloads, magnetic for short circuits, and sometimes instantaneous trips). The exact clearing time depends on the current level, device rating, and coordination with upstream protection. Because these devices are built with different protective philosophies and specifications, they do not share a single typical fault-clearing time such as 1.5 cycles. Some faults may clear in well under a cycle, while others—depending on the protection settings and fault magnitude—may take longer. That’s why the statement is not true.