a risk of shock protection circuit is disclosed , which comprises a capacitor that charges whenever there is a voltage between a ground on a lamp ballast and earth ground . if the capacitor exceeds a predetermined threshold voltage , the capacitor causes a gate to shunt current away from a tertiary winding in a control circuit , which in turn reduces impedance reflected by the tertiary winding back on to primary and secondary windings in the ballast circuit . the reduced reflected impedance causes the operating frequency of the ballast to increase , reducing the voltage between the ballast ground and earth ground until it is safe for human contact . in this manner , a human replacing a lamp connected to the ballast can be protected from shock despite a failure to disconnect the power to the lamp ballast prior to lamp replacement .