What is a Surge?

Surges, or transients, are brief overvoltage spikes or disturbances on a power waveform that can damage, degrade, or destroy electronic equipment within any home, commercial building, or manufacturing facility. Transients can reach amplitudes of tens of thousands of volts. Surges are measured in microseconds.

The presence of sensitive electronic equipment such as computers, answering machines, microwaves, and other microprocessor-based equipment is growing exponentially in virtually every aspect of life.  Surges  can cause damage,  resulting in:

• Equipment loss or damage
• Lost productivity/down time
• Other financial losses

For more detail about what a surge is relative to different facility types, visit the commercial, industrial, or residential section.

What is at Risk?

Here is a partial list of vulnerable equipment in and around your commercial or industrial facility or home:

• Industrial or commercial equipment - machinery, motors, HVAC, cash registers
• Office equipment - personal computers, printers, fax machines, copiers, modems
• Home appliances and theater equipment
• Telephones and answering machines
• Security systems
• Sprinkler systems
• Invisible fences
• Landscape/pool/outdoor lighting

For more detail about what is at risk, visit the commercial, industrial, or residential section.

What is a Surge Protective Device (SPD)?

SPDs are devices that can attenuate, or reduce, transient voltage levels and noise.  They're also called transient voltage surge suppressors, or TVSS. Industry professionals refer to these devices as surge protective devices, or SPDs. The terms TVSS and SPD are interchangeable. 

Surge protective devices are designed to reduce potentially damaging short-duration transients present on utility power lines, data networks, telephone lines, closed circuit and cable TV feeds, and any other power or control lines connected to electronic equipment. 

For more detail about SPDs used in specific facilities for these purposes, visit the commercial, industrial, or residential section.

How do SPDs Work?

In the simplest terms, SPDs prevent damaging transient voltage surge levels from reaching the devices they protect however a SPD doesn't necessarily reduce the surge to zero amplitude. It reduces it to a level that can safely be passed through to the load. 

For more detail about how SPDs work, visit the commercial, industrial, or residential section.

What are SPD Technologies?

The components used in SPDs vary considerably. Here is a sampling of those components: 

• Metal oxide varistor (MOV)
• Silicon avalanche diode (SAD)
• Gas tubes
• LCR filters
• TVSS (transient voltage surge suppressor) hybrid

These components vary in their:

• energy capability
• availability
• reliability
• cost
• effectiveness

For more detail about SPD technologies, visit the commercial, industrial, or residential page for "What is an SPD?".

What about Grounding?

The goal of any grounding system is to provide a low impedance path for fault or transient currents to the earth. “Grounding” may be described as the process of making this electrical connection to the general mass of the earth. 

The primary characteristic that determines the effectiveness of a grounding system is the impedance the connection provides to the earth.  A grounding system appears to such transient events, such as surges, an impedance, rather than a resistance. 

For more detail about grounding, download the brief white paper, Ground Resistance or Impedance?

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