During switching of a capacitor, transient currents to the order of 200 times the rated current can flow stressing the capacitor and the switching contacts immensely. This can lead to damage or welding of contacts of the contactors. The modern Power Factor Correction systems use new generation Viz Contactors designed to switch the capacitors first through contact block of three early make auxiliary contacts in series with current limiting resistors(also called pre charging resistor) to limit inrush current to the value within contactor rated capacity. Normal rated capacitor current is carried by main contacts which after closing after about 5 milliseconds, effectively bypass the damping resistor. The leading contacts then open up and no currents flows through them.