What is the technical rationale for minimizing SPD lead length and maintaining straight wire routing during installation?
Product Line:
Surge Protective Devices (SPDs)
Resolution:
To ensure optimal system performance, the SPD (Surge Protective Device) should be installed as close as possible to the electrical panel or circuit it is protecting. Minimizing lead length is critical, as each additional foot of wire introduces approximately 160 volts of added clamping voltage during a surge event (based on a 6 kV / 3 kA, 8/20 µs waveform).
According to UL® 1449 standards, the Voltage Protection Rating (VPR) is measured six inches from the SPD enclosure. However, actual performance can degrade significantly with increased wire length. For best results, it is recommended to maintain a lead length of less than 5 feet, using the shortest and straightest possible path between the SPD and the panel. Longer distances reduce protection effectiveness, especially at the farthest panel locations.
White Paper https://www.se.com/us/en/download/document/ASC-SPD-WP-CONSIDERATION-SPD/
Released for: Schneider Electric USA
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