Concerns with Common Mode SPD Application

Concerns with Common Mode SPD Application Key Takeaways Common mode (phase-to-ground mode and neutral-to-ground mode) suppression can create unwanted performance outcomes for end users. Common mode suppression can create touch safety hazards. Metal oxide varistors (MOVs) are surge protective device (SPD) components designed to absorb transient overvoltage and dissipate energy as heat. Introduction An electrical […]

Integrated vs. Externally Mounted Surge Protective Devices

Integrated vs Externally Mounted Surge Protective Devices Key Takeaways Integrated surge protective devices (SPDs) create limitations when sourcing parts or replacements that non-integrated SPDs do not. Integrated SPDs can damage the electrical distribution system during failure conditions; non-integrated SPDs cannot. Externally mounted SPDs offer serviceability without the need to de-energize the entire load center; integrated […]

Common Misconceptions About SPDs Nominal Discharge Current Ratings: Part Two

Common Misconceptions About Surge Protective Devices Nominal Discharge Current Ratings: Part Two Key Takeaways The existing single-pulse In test is inadequate to assess robustness or safety. Increasing the kA of a single-pulse test will not give an accurate representation of MOV-type surge protective device (SPD) responses to multi-pulse lightning flashes. Service entrances where ANSI/UL 1449 […]

Common Misconceptions About SPDs Part One: Nominal Discharge Current Ratings

Common Misconceptions About Surge Protective Devices Part One: Nominal Discharge Current Ratings Key Takeaways Nominal Discharge Current Rating (In) tests are not based on normal operating conditions. In ratings are not indicative of surge protective device (SPD) safety nor robustness. The vast majority of SPD failures occur due to temporary overvoltage (TOV) conditions, which the […]

Modern ATS Components Are Highly Susceptible To Failure Caused By Transient Voltage

Modern ATS Components Are Highly Susceptible To Failure Caused By Transient Voltage Key Takeaways Transient voltage is inherent to AC power systems. Modern automatic transfer switches (ATSs) contain sensitive components that are highly susceptible to damage caused by transient voltage. Voltage monitoring control boards and control power supplies commonly fail due to damage caused by […]