The main circuit breaker sits atop an electrical panel to handle the high amperage load of incoming feeder wires, shutting off power to an entire building during severe overloads or surges. It also functions as the master system shutoff for maintenance and repairs.
Your electrical panel is full of circuit breakers running from top to bottom. For convenience, breakers are usually numbered and mapped, with odd-numbered breakers on the left and even-numbered circuits along the right. Sitting atop both rows of branch circuit breakers is a single larger circuit breaker—usually located dead center at the top of the panel, though placement can vary based on installation.
Quick Reference: Main Circuit Breaker Specifications & Amperage
| Feature / Metric | Functional Details |
| Incoming Voltage | Brings 240 volts into the home via two main service wires, each carrying 120 volts to individual hot buss bars. |
| Amperage Ratings | Typically rated from 100-amps, 150-amps, to 200-amps or higher (older homes may feature 60-amps). |
| Primary Purpose | Shuts off power to the entire building if overall load demand grows too high, surges occur, or branch safety fails. |
How to Safely Shut Down Your Electrical System
When using the main breaker as a system shutoff for major electrical work, follow this recommended procedure:
- Shut off each individual circuit breaker in the panel, one at a time.
- Flip the lever on the main circuit breaker to the OFF position.
- To restore power: Reset the main breaker to the ON position first, then turn on each individual circuit breaker one at a time to avoid sudden power demands.
Safe Procedure for Resetting a Tripped Main Breaker
If the main breaker trips due to a lightning strike, utility surge, or overload, use the following safety steps:
- Turn off branch circuits: Switch off all individual circuit breakers controlling branch circuits before touching the main breaker. This prevents motors and heavy loads from activating simultaneously.
- Protect yourself: Stand off to the side of the panel, wear safety glasses, and turn your head away when flipping the lever to protect against potential electrical flashes or sparks.
- Restore individual loads: Turn on each individual circuit one at a time by resetting its lever to the ON position.
Note: If the main breaker trips repeatedly, contact a licensed professional immediately, as the issue may involve a short circuit or a failed component.
Contact TSCA Electrical Group today for expert assistance with your electrical panel upgrades or industrial requirements, or explore our complete catalog of industrial electrical products and services.