When a wire is connected to a circuit breaker in an electric panel, the insulation should only be stripped back enough so that, when it is fully inserted in the breaker, no insulation is under the setscrew terminal and no bare wire extends past the side of the breaker. it’s called “overstripped” when bare wire is left exposed outside of the breaker, as in the photo above.
Overstripped wires are both a shock hazard and can cause a short circuit if they contact any bare ground wires nearby or the panel box. In the photo below, there is also the potential for the overstripped wire to come in contact with the neutral/ground bus bar below it to short out.
