Which of the following is a true statement regarding Type 1 surge protective devices?

The correct statement regarding Type 1 surge protective devices is that they are suitable for the supply side of the service disconnect. Type 1 surge protective devices are designed to be installed before the service disconnect, which allows them to protect all downstream equipment from voltage surges that may occur on the utility side. This positioning is critical because it ensures that any transients are mitigated before they enter the building's electrical system, providing broad protection.

In contrast, options that suggest they must be installed downstream of the service disconnect are not accurate, as this location would actually negate some of the protective benefits these devices offer. Additionally, stating that they can be installed anywhere in a circuit overlooks the specific application requirements that Type 1 devices are designed for. Finally, the assertion that they can only be used in residential applications is misleading, as Type 1 surge protective devices are also applicable in commercial and industrial settings where surge protection is needed at the service entrance.