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How should Surge Protection be sized for my application?

We recommend using THOR SYSTEMS’ Site Shield 3g Risk Assessment Guide. The “Site Shield” provides a coordinated protection scheme throughout the facility. Installation locations with higher exposure levels (normally service entrance applications and critical equipment) have higher surge current ratings, while installations within the distribution system typically have lower exposure levels and therefore lower surge Read the full article…


What are the Modes of an electrical system that need Surge Protection?

Some manufacturers specify all ten protection modes contain suppression elements for true “All Mode” protection. Claims are made that indicate IEEE and NEMA standards call for all modes to be protected (IEEE C62.41.1 – 2002, C62.41.2 2002, and C62.45 – 2002; NEMA Publication LS1 – 1992). In reference to all of these standards, the implication Read the full article…


Why not Integral Surge Protection?

The main issue concerning Surge Protection Devices (SPDs) suppression units mounted integral to the distribution equipment is the risk of collateral damage to the distribution equipment in the event of a failure of the SPD. The IEEE Green Book points out this concern in Section 8.4.2.5. Another concern relative to arc flash discussions is integral Read the full article…


Why Modular vs. Non-modular Surge Protection?

Modular devices are specifically applied for the more harsh service entrance, main distribution, and where protected equipment criticality is a vital consideration. Modular devices that experience component failures can quickly return surge protection to full rated capacity, limiting the amount of time critical equipment is unprotected. Non-modular designs are typically applied for lower ampacity distribution, Read the full article…


Is there a need for more than one SPD?

This answer depends on the application. If protection is only being considered for a single piece of equipment, one SPD may be appropriate. If the complete electrical system is being considered, a cascaded installation is typically recommended. A cascaded installation (referenced in IEEE Guide for the Application of Surge-Protective Devices for Low-Voltage [1000 V or Read the full article…


Electrical power quality problems cost the United States industries over $100 billion annually
80% of voltage surges and transients are caused by changes in electrical demand, inside the user's facility