Transient spikes and ground contamination are not the only problems faced by today’s sensitive electronics. There are also sustained over-voltage conditions, sometimes called extreme voltages. Many surge suppression devices will not be able to protect equipment from sustained over-voltages. These conditions can occur for multiple reasons. For example, a power pole may be damaged during a storm or accident. Also, in many countries, such as USA and Canada, lost or intermittent neutral wiring of a multiple-zone system can result in a sudden connection well in excess of 208 volts AC.
Many surge suppression devices are not equipped to handle these kinds of conditions. Without proper protection, the end result is destroyed equipment, or at best, a destroyed surge suppression system.
Furman’s Extreme Voltage Shutdown (EVS) constantly monitors incoming voltage, and once any over-voltage condition over 137 volts AC is detected, a relay opens which immediately shuts down the unit and all connected equipment. An indicator light informs the user there is a problem. Once the condition has been corrected, the unit may be reset or auto-reset (depending on model) and will operate normally.