"Surge noise is due to the dielectric varistor material and occurs at high frequency noise or high voltage surge and also in situations when surging is at extremely high speeds."

"Surge noise occurred as a result of inserting and removing an electrical appliance
plug. The average surge noise detected in the fast-response interrupting interrupting module is 360 mV and 250 ns. However, the maximum surge noise voltage may reach 3 V. The module control voltage was set to 2.4 V. It must be lower than this surge noise level...."