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Main Circuit Breaker

Circuit Breakers

Circuit breakers protect a circuit from overloads and short circuits. When the current exceeds the rating of the breaker, it will trip. Circuit breaker ratings for household use are typically 15, 20, and 30 amps.

How to Reset a Circuit Breaker

Important! Before resetting a breaker, stand to the side of the electrical panel, do not stand in front. In certain rare situations while resetting a breaker, it could arc flash and injure a person standing in front of the panel.

To reset the breaker, turn the handle away from the middle of the panel (off position) and then turn the handle toward the middle of the panel (on position).

Can I Use a Circuit Breaker as a Switch?

It is fairly common for circuit breakers to act as light switches in warehouses, stores, and commercial environments. It is OK to use a circuit breaker as a switch if the following ratings are listed on the breaker.

GFCI and AFCI Circuit Breakers

Ground fault circuit interrupter (GFCI) and arc fault interrupter (AFCI) breakers work the same as standard breakers. The GFCI breaker will also trip when current flows to ground instead of back to neutral. The AFCI breaker will also trip when it detects an arc fault. To test either breaker, press the white button and it should trip. If it does not trip, it needs to be replaced. Reset like a standard breaker.

Nuisance Circuit Breaker Tripping

Nuisance tripping happens when a circuit breaker trips during normal conditions (circuit is not overloaded, no ground fault, no apparent arc fault). It could be that the breaker needs to be replaced, or that a load is causing a ground or arc fault. An old vacuum cleaner may be tripping a good AFCI breaker. If a load trips an AFCI breaker, try plugging the load into another circuit with AFCI protection.

GFCI or AFCI Circuit Breaker

GFCI and AFCI Breaker Wiring

A GFCI and AFCI breaker comes with a white neutral wire attached to it. This wire is connected to the neutral bar in the electrical panel. The circuit neutral wire is connected to the GFCI or AFCI breaker. Ground is not shown in these diagrams.

GFCI and AFCI Circuit Breaker Wiring Diagram


How to Troubleshoot Circuit Breakers

TROUBLESHOOTING CIRCUIT BREAKERS ARE DONE ON AN OPEN LIVE ELECTRICAL PANEL AND SHOULD ONLY BE DONE BY A QUALIFIED ELECTRICIAN. REMOVING WORKING ON A LIVE ELECTRICAL PANEL RUNS THE RISK OF ELECTROCUTION OR SEVERE ARC FLASH!!! THESE INSTRUCTIONS ARE FOR REFERENCE ONLY.

There are two tests for breakers, voltage and current.

Voltage test - With a solenoid tester or a multimeter set on AC voltage, one lead is placed on the neutral or ground bar, and the other lead is placed on the circuit breaker 120 V terminal. If voltage is not present with the breaker on, it needs to be replaced.

Current test - The clamp of a multimeter/clamp meter is placed around the circuit wire connected to a breaker. If the breaker trips while the current is below the rating of the breaker, it needs to be replaced.

                             Voltage Test using Multimeter                                   Current Test using Clamp Meter

               Voltage test using test leads                    Current test using clamp

Circuit Breaker Handle Position

Tripped breaker position, handle in between on and off position.

A circuit breaker is in the “on” position when the handle faces the middle of the electrical panel. The “off” position is away from the middle of the panel.

If power is lost to lights, receptacles, or appliances it may be a tripped circuit breaker. When a circuit breaker trips, the handle is usually in between on and off position (sometimes in the “off" position).

“On” position, handle toward middle of panel

The main circuit breaker (disconnect) to a house is either located on the meter panel, or at the top or bottom of the main electrical panel. It can be used to shut power down to the whole house. Including the electrical panel.

How Circuit Breakers Work

See How Circuit Breakers Work by Southland Electrical Supply.

Main Circuit Breaker

Circuit Breakers

Two-Pole Circuit Breakers

Two-Pole Circuit Breaker

Two-pole (double-pole) circuit breakers are used to protect a 240 volt (V) circuit. A 240 V circuit consists of two 120 V circuits, A and B phase. 240 V is used for central air conditioners, electric dryers, electric ranges, etc. Since the handles are connected together, when one pole (A or B phase) trips, the other pole is automatically turned off.

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Main Circuit Breaker