When the reed contacts open they break a circuit. If there is a voltage and current present when the contacts open they will stop the current flow. Once the contacts open the voltage that was driving the current will reappear across the contacts. This is normally not an issue unless the voltage is generally higher than 250 volts. At this level and higher when the contacts attempt to open they will begin to draw an arc. The arc is over 2000°C and will melt some of the metal on the contacts. The higher the current flow the stronger the arc and therefore more melting of the metal. Some of this melted metal will transfer to the other blade. If enough metal transfers, the contacts will stick. Breaking more than 10 ma can becomes a real problem with the higher voltages. Quenching the arc refers to the stoppage of the arc and/or metal transfer. If you are having to break high voltages care must be advised to minimize the amount of current flowing at the time of contact opening to minimize the metal transfer. Minimizing the current will prolong the life of the contacts.