What do you think of when you hear the saying "blow a fuse?" Do you think of the panel in your house where you replace a little glass bulb with a wire in it? Or do you think of the panel where you flip a switch to restore your electricity? If you think of the switch, then you actually have a circuit breaker in your house. This is a reusable electric switch that cuts off the circuit when the current is too high, preventing your wiring from heating up and potentially causing a fire.
Fuses are an older way of interrupting the flow of current. A fuse is simply a wire that heats up and breaks when the current is too high, disrupting the electricity. To turn it back on, the fuse has to be replaced. Newer houses and electrical installations use circuit breakers instead. All wiring and appliances in a house are on circuits. A circuit is essentially a closed loop of wire, allowing a return path for current to flow on. It consists of a "hot" wire coming from the source of electricity, and a "neutral" wire that connects to the ground. When the circuit is closed, the current can then flow, as it moves from areas of higher concentration to lower.
The current is the rate of flow of the electrical charge. Current is the voltage divided by resistance. Voltage is the force making the charge move and resistance is determined by the size and properties of the wiring and appliances. Voltage and resistance working together will vary the amount of current. Current increases when there is more voltage or less resistance, allowing the charge to flow faster.
When the charge moves to quickly, the wire or appliance the charge is moving through may not be able to handle it. Or, something will cause the hot wire to connect to the neutral wire or something else connected to the ground. A lack of resistance in the circuit will cause the charge to move freely. Either way, increased current will trip the circuit breaker switch.
Many small household circuit breakers consist of an electromagnet or a metallic strip that will cause a terminal in the breaker to move and open the circuit. Under normal conditions, current flows across the breaker from one terminal to the other and out the other end. But as current becomes too high, it will cause an electromagnet to move or a metal strip to bend, opening the circuit and stopping the flow of electricity. An arc of electricity is created in a chamber in the breaker when this happens, but in a household one, air is enough to extinguish it. Larger circuit breakers may use different methods of extinguishing this arc, such as a vacuum chamber, gas, or oil.
All the wiring in a house flows through circuit breakers. They're found on a panel in the house, usually in the basement or a closet. Some large appliances, like air conditioners or refrigerators, will be on their own circuits and have their own switch. When the circuit breaker is tripped, it will appear in the middle or off position of the switch. To reset it, unplug or turn off all devices and appliances on that circuit. Then make sure that all switches have been moved to the off position. Then simply move everything back to on. It's then safe to turn your appliances back on. Your electricity is back to normal.
If the circuit trips again with nothing plugged in or turned on, the breaker or electrical wiring may have a fault in it and need to be replaced. If it trips when something is turned on, there may be a short in the appliance or it is placing too much load on the circuit. If resetting the circuit breaker doesn't restore your electricity, there may be a wiring fault, a defective outlet, or your circuit is on a different type of circuit breaker, such as a ground fault circuit interrupter (GFCI). This is one designed to prevent electrocution and monitors the amount of current. These are often used in locations like the kitchen and bathroom. GFCI outlets have 'test' and 'reset' buttons on them. To trip the circuit, press the test one. To restore the circuit, simply press reset and the electricity should return to normal.
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