Change Summary

• Voltage surge protective devices (SPD’s) are required to be installed in or on all switchboards and panelboards of emergency systems
• These surge protective devices and products must be listed
• Requiring SPD’s ensures emergency electrical distribution systems will continue to deliver reliable power to vital life safety loads in the event of a voltage spike

Expert Analysis

Surge protective devices or SPD’s are covered by the NEC in Article 285 Surge-Protective Devices (SPD’s),1000 volts or Less; by Underwriters Laboratories in UL 1449, Standard for Surge Protective Devices 3rd Edition and by IEEE in C62.41 IEEE Recommended Practice for Surge Voltages in Low-Voltage AC Power Circuits. For the 2014 NEC, Section 700.8 now requires a voltage surge protective device must be installed in or on each emergency system switchboard and panelboard. The proper type and rating of the SPD must be suitable for the application. This requirement helps ensure that emergency electrical distribution systems will continue to deliver reliable power to vital life safety loads in the event of a voltage spike.  Voltage surges resulting from lightning strikes or due to various sources within an electrical system, such as switching of power electronic devices, can destroy both the electrical distribution equipment and the loads it supplies. Electrical equipment damage can be from a single lightning strike nearby or the accumulative effects of multiple voltage surges from sources within an electrical system.

Type 2 Modular Surge Protective Devices

Leviton’s 74000 and 75000 Series panel mounted surge protective devices provide seven-mode protection in WYE-configured, 3-phase AC systems. Designed for most industrial and commercial environments with critical operations, these panels offer complete protection at the building entrance and distribution panel.