For a Category C TVSS panel, which installation location is correct?

In a Category C Transient Voltage Surge Suppressor (TVSS) panel, the correct installation location is on the load side of an Automatic Transfer Switch (ATS).

This placement is vital because Category C TVSS devices are designed to protect sensitive electronic equipment from transients that may occur downstream of the ATS. By installing the TVSS on the load side, it ensures that protection is provided directly to the equipment that is most vulnerable to surges, including computers, servers, and other delicate electronic systems.

Positioning the device in this manner allows it to intercept transients that may be introduced not only from the normal utility supply but also from the generator or other backup power sources activated by the ATS during a power failure. This ensures comprehensive protection at all times, regardless of the source of power being utilized.

In contrast, installing a TVSS at the service entrance panel limits the protection to the entire facility but does not account for specific surges that may occur once the power has been conditioned by the ATS. Similarly, other locations mentioned do not provide the optimal protective strategy when dealing with sensitive equipment connected through an ATS.