Electrical Exam Term
Main Breaker
The primary circuit breaker in an electrical panel that controls power to the entire panel and serves as the main disconnecting means for the building.
Detailed Explanation
The main breaker is rated to handle the full amperage capacity of the service (commonly 100A, 150A, or 200A for residential). NEC 230.70 requires the service disconnecting means to be installed at a readily accessible location nearest the point of entrance of the service conductors. Some installations use a main lug only (MLO) panel with an external disconnect.
Premium Study Material
Don't just memorize terms.
Master the exam.
Get access to 650+ exam-like questions, detailed explanations, and specific state law-supplements for your state.
Pass Guarantee
State-Specific Content
Unlimited Practice Tests
Instant Feedback
Practice QuestionEasy
Which of the following best describes the concept of Main Breaker?
Start Practicing →