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Every time an electrical power device (for example: heaters, lamps, motors, transformers or similar power loads) turns on or off, its switch, relay or contactor transitions either from a CLOSED to an OPEN state ("BREAK") or from an OPEN to a CLOSED state ("MAKE"), under load, an electrical arc occurs between the two contact points (electrodes) of the switch.
The electric arc occurs between the contact points (electrodes) both during the transition from closed to open (BREAK) and from open to closed (make) when the contact gap is small and the voltage is high enough. Heating due to arcing and high current density can melt the contact surface temporarily.
An arc-fault circuit interrupter (AFCI) or arc-fault detection device (AFDD) [1] is a circuit breaker that breaks the circuit when it detects the electric arcs that are a signature of loose connections in home wiring. Loose connections, which can develop over time, can sometimes become hot enough to ignite house fires.
An electric arc between two nails. An electric arc (or arc discharge) is an electrical breakdown of a gas that produces a prolonged electrical discharge. The current through a normally nonconductive medium such as air produces a plasma, which may produce visible light. An arc discharge is initiated either by thermionic emission or by field ...
If the voltage is high enough, an arc may be struck even without an inductive load. Regardless of how the arc forms, it will persist until the current through the arc falls to the point too low to sustain it. Arcing damages the electrical contacts, and a sustained arc may prevent the open contacts from removing power from the system being ...
When the electric field applied across an insulating substance exceeds in any location the threshold breakdown field for that substance, the insulator suddenly becomes a conductor, causing a large increase in current, an electric arc through the substance. Electrical breakdown occurs when the electric field in the material is strong enough to ...
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If the power supply continues to supply current, the spark will evolve into a continuous discharge called an electric arc. An electric spark can also occur within insulating liquids or solids, but with different breakdown mechanisms from sparks in gases. Sometimes, sparks can be dangerous. They can cause fires and burn skin.