What sets Type 1 and Type 2 Surge Protective Devices (SPD) apart from each other?

Issue:
What sets Type 1 and Type 2 Surge Protective Devices (SPD) apart from each other?

Product Line:
TVSS/SPD

Environment:
Application

Cause:
Clarification

Resolution:

​​​​​​​Type 1 Surge Protective Devices (SPDs):

Type 1 SPDs are permanently hard-wired devices intended for installation between the secondary side of the utility service transformer and the line side of the main service equipment’s overcurrent protective device. They may also be installed on the load side of the main service equipment. These devices are designed to protect against external surges, such as those caused by direct lightning strikes or utility switching events, before the surge reaches the main service panel.

Type 2 Surge Protective Devices (SPDs):

Type 2 SPDs are specifically designed for installation on the load side of the main service equipment’s overcurrent protective device. While they can be located at the service entrance, it is critical that they are installed after the main overcurrent protection. Type 2 SPDs primarily protect against internally generated surges, such as those caused by switching of inductive loads

System-Level Protection Strategy:

Type 1 and Type 2 SPDs serve complementary roles in a layered surge protection strategy:

• Type 1 SPDs provide the first line of defense against high-energy surges entering from external sources.
• Type 2 SPDs offer downstream protection for sensitive equipment and circuits from residual or internally generated surges.

Together, they help ensure comprehensive surge protection across the electrical system.

Released for: Schneider Electric Canada