Surge Protection for Uninterruptible Power Supplies


Critical Operations Power Systems are generally installed in vital infrastructure facilities that, if destroyed or incapacitated, would disrupt national security, the economy, public health or safety; and where enhanced electrical infrastructure for continuity of operation has been deemed necessary by governmental authority.

Uninterruptible Power Supplies (UPS) are commonly deployed to provide short-term backup power for information technology equipment and facilities. The following narrative explains how surge protection devices (SPDs) can be deployed to protect UPS equipment from damages that can be caused by excessive transient overvoltages.


Uninterruptible power supplies provide backup power to critical infrastructure equipment and systems. UPS systems, like other devices containing sensitive electronic components, are susceptible to transient overvoltages from lightning or switching-related events. IEEE 1100 provides recommendations for protecting UPS equipment from associated risks. For complete protection, IEEE recommends SPDs be applied on UPS inputs and bypass switch inputs. The selected SPDs should offer premium protection, meet or exceed the short circuit current rating of the associated electrical circuits, and provide protection meeting or exceeding UPS manufacturer recommendations.