Am overcurrent devices are equivalent to which type MCB?

• A. B type
• B. D type
• C. C type
• D. A type

Answer: (B)

The main concept is how MCBs are categorized by their instantaneous trip characteristics, which determines how quickly they respond to an overcurrent fault. A protective device that reacts when current rises to about three to five times its rated current provides fast short-circuit protection while typically not tripping for normal inrush in many general circuits. This fast-acting, lower-threshold curve matches the way general overcurrent protection is expected to behave in standard installations: it interrupts faults quickly to prevent conductor damage, yet stays clear for normal load surges. Other curves have higher instantaneous trip thresholds, so they’re chosen for circuits with larger inrush currents (like motors) where nuisance tripping would be an issue. Therefore, the type that best aligns with general overcurrent protection is the one with the 3–5 In instantaneous trip characteristic.