Why it sparks when plugged into the wall outlet?

Answer 1

If you are plugging/unplugging under load it means that there is some abrupt energy change causing a spark. Inductors (motors) try to prevent changes in current. So if you unplug one while on it will spark. Capacitors try to prevent changes in voltage. So if you plug something in with a switchmode supply, it will spark as the input capacitors try to quickly charge. If the outlet is sparking when the appliance is off, or when the plug is not being handled, then you have a fire hazard. Cut power to that circuit at the breaker. Replace the outlet or call an electrician.

Answer 2

Because of electronic discharge in gas... when the plug is pulled to far, the electrons don't tend to travel too long in air, under atmospheric pressure. But until a short distance after removal of the plug, the electrons overcome the resistance in air and travel to the plug, so the spark (analogous to cathode ray tube). The intensity of spark depends on the voltage at the terminal.

Answer 3

Anytime an electrical circuit is completed or broken, if the voltage across the circuit is high enough, either a spark or arc will jump the remaining gap between the contacts. If it is just a spark it is simply electrical breakdown of the dielectric of the air between the contacts, in most cases normal airflow will restore the dielectric causing the spark to go out. If it is an arc then the air between the contacts has ionized, this can be very dangerous as the ionized air can still conduct with the contacts far apart and can badly burn the contacts and even ignite nearby materials.

Normal household AC voltage (e.g. 120 VAC in the US, 240 VAC in much of the rest of the world) is high enough to do this very easily. Lower voltages (e.g. 12 V, 24 V) are generally too low to do this, but if the circuit powered by such low voltage contains significant inductance the "kick back" of the inductance when the circuit is broken can easily be tens of thousands of volts and can generate very dramatic sparks and arcs.

Answer 4

It generally means that you should turn that circuit off at the breaker panel until the electrical outlet can be replaced.

Answer 5

receptacles are worn out