Insulated case circuit breakers, low voltage power circuit breakers, and molded case circuit breakers are all types of circuit breakers rated as ?

• A. Ground fault devices
• B. Branch circuit overcurrent protectives
• C. Main service disconnects
• D. Arc fault protectors

Answer: (B)

The main idea here is that these devices are all used to protect branch circuits from overcurrent. Insulated case, molded case, and low voltage power circuit breakers are built in common panelboard formats and are designed to interrupt current when it exceeds the safe limit for a specific branch. That makes them branch circuit overcurrent protectives—the function they share is limiting current on individual branch circuits to prevent overheating and fires.

Ground fault and arc fault protections are specialized features that some breakers may include, but they describe different protective functions (faults to ground or arcing patterns). The main service disconnect is a larger device at the service entrance that can shut off power to the whole installation, not just a single branch circuit.