Gg overcurrent devices are equivalent to which type MCB?

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

Answer: (A)

The main idea is matching protective device characteristics to how circuits behave under fault conditions. A general-purpose overcurrent device like gG is designed to protect cables and normal loads, reacting to short circuits with a relatively quick trip but not nuisance-trip under everyday inrush. This behavior lines up with a B-type MCB, which trips quickly at about 3–5 times the rated current for short-circuit faults while staying stable during normal operation and small overloads. The other MCB types have higher instantaneous trip thresholds (C and D) or are not standard for this context, so they aren’t the right match for a general-purpose, everyday protection role. Hence, gG overcurrent devices are equivalent to B-type MCBs.