2365 203 #17 - Circuit Protection Devices

What is the main purpose of a circuit protection device?

• Increase energy efficiency

• Prevent voltage drop

• Automatically disconnect supply during faults

• Boost current flow

What does MCB stand for?

• Manual Circuit Breaker

• Miniature Circuit Breaker

• Multi-Core Breaker

• Maximum Current Blocker

What fault does an MCB protect against?

• Earth faults only

• Overcurrent due to overload or short circuit

• RCD tripping

• Undervoltage

What does a fuse do?

• Reduces current continuously

• Trips repeatedly

• Melts and disconnects supply when current exceeds a set limit

• Indicates voltage levels

What is the main function of an RCD?

• Protect against overload

• Control heating

• Detect and disconnect earth leakage faults

• Prevent overheating

What does RCBO stand for?

• Residual Core Breaker Output

• Residual Current Breaker with Overcurrent protection

• Reverse Current Breaker Overload

• Remote Controlled Breaker Output

Which device combines the functions of an RCD and an MCB?

• RCCB

• Isolator

• RCBO

• Contactor

What does the number on an MCB (e.g. B32) represent?

• Cable size

• Disconnection time

• Rated current in amps

• Voltage drop

What curve types are associated with MCBs?

• A, B, C, D

• X, Y, Z

• B, C, D – indicating tripping characteristics

• 1, 2, 3

Which MCB curve type is typically used for domestic installations?

• A

• B

• C

• D