In which scenario is the installation of a Type 1 TVSS considered appropriate?

The installation of a Type 1 Transient Voltage Surge Suppressor (TVSS) is considered appropriate when it is connected to the line side of the service disconnect. This placement ensures that surge protection is applied before the power enters the building's electrical system, providing a crucial first defense against voltage spikes that could damage equipment or compromise safety.

By placing the TVSS on the line side, it can effectively mitigate surges from external sources, such as lightning strikes or utility switching actions, before they have an opportunity to reach sensitive electronic equipment. This strategic location allows the TVSS to intercept and redirect excessive voltage away from the circuits and devices downstream, helping to maintain the integrity of the power system and protect the equipment connected to it.

Additionally, TVSS devices on the load side of the panel or connected directly to the ground system would not offer the same level of protection against incoming surges, as they would only respond to surges that have already penetrated the panel or might not be adequately grounded to dissipate the energy. Therefore, connecting the Type 1 TVSS to the line side of the service disconnect is essential for optimal protection.