Sometimes a squirrel
will mis-step and accidentally touch two conductors on a power line
, or touch a conductor
and something ground
ed, like the case of a pole pig
Now, power distribution lines are generally run at around 14kV, or 14,000 volts for the metric-impaired. To this voltage, a nice moist creature like a squirrel is practically a short circuit.
The squirrel vaporization process begins, drawing hundreds, maybe thousands of amps, resulting in the tripping of the circuit breaker which feeds the line at the upstream substation. A nice bright blue flash also accompanies the event.
The power goes out.
The circuit breaker automatically recloses after about two seconds. If the squirrel has been vaporized, all is well and the power returns. Otherwise the process repeats until the fault (charred squirrel) is cleared.
This is a frequent cause of brief repeating power interruptions in semi-rural areas. Stubborn squirrels can take two or three open-reclose cycles to clear, especially on lower voltage distribution lines.