What does the term headroom mean with regard to surge protection devices?
Headroom is Line Voltage Variation Allowance (LVVA) of the protector. This is the difference between the nominal line voltage amplitude and the voltage level that the surge protector will conduct or turn on with. Usually headroom is expressed as a percentage of the nominal line voltage, like 15% or 20%. Electrical equipment, like a surge protector, has limits with regard to the AC voltage applied that it can handle. Electrical equipment can handle these common utility swells without damage or disruption. But a surge protector with inadequate headroom may be damaged as it is not designed to conduct such currents and may short out as a result of the AC current flowing through the protection components. The most reliable surge protectors are able to ride through common utility voltage variances (i.e. +/-20%) without conducting, while still providing exceptional protection. A protector with inadequate headroom may be damaged and taken off line by an otherwise harmless AC power frequency vo
