Quick answer
A small spark when plugging in an appliance is often normal. Large sparks, repeated sparking, or a burning smell mean the socket must be checked immediately.
A very small, brief spark when you plug in an appliance is sometimes normal — it happens as the plug makes contact with the energised socket. However, there are warning signs that mean you should stop using the socket immediately and call an electrician: a large or sustained spark, a burning smell, scorch marks around the socket face, the socket feeling warm or hot to the touch, or repeated sparking every time you use it. These signs indicate a loose connection, damaged socket, or overloaded circuit. Do not use a socket that shows these signs — turn off the circuit at the consumer unit and get it checked.
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