Hi,

One of the circuit in my house has all of a sudden died. It happened
when I was trying to plug in a (working) device in the outlet, and
something in the outlet popped with a bright spark. Now the circuit is
down, except when I use a voltage detector it beeps and when I use a
meter it shows a voltage of 3V. I don't think it's the circuit breaker
because I swapped it out and it didn't affect anything. What could
this be?

Many thanks in advance!