Best Surge Protector Ratings

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What exactly are Surge Protector Ratings? What information should be included to help determine a quality SPD?

Although there are a number of categories that are standard, it can vary depending on who’s marketing material you’re studying, who's website you're reviewing and the type of SPD in question.

Overall, the purpose of this data is to provide an overview of safety and capabilities for a particular SPD. Among other things, surge protector ratings are often used to compare and contrast competing devices.

Generally... surge protector ratings data may include:

Power Protection Devices

  • Clamping Voltage
  • Energy Absorption/Joules
  • Reaction Time
  • Modes of Protection
  • Short Circuit Ratings (SCCR)
  • Voltage Protection Ratings (VPR)
  • Circuit Interruption/Fusing
  • Peak Surge Current
  • Insertion Loss
  • Filtration Technology
  • MCOV
  • Type
  • Let-Through Voltage
  • Certifications
  • Warranty

Data Line & Telecom Protection Devices

  • Modes of Protection
  • Peak Surge Current
  • Max Operating Voltage
  • Max Continuous Operating Current
  • Data Rate
  • Let-Through Voltage
  • Resistance
  • Certifications
  • Warranty

Surge Protector Ratings
Data We Focus On

With over 30 years of SPD design, SPD testing and in-the-field experience, we're confident we know what to look for when reviewing surge protector ratings. We're comfortable navigating through the confusing world of marketing material and spec sheet information.

As listed above, there are a number of characteristics that can be used to create Surge Protector Ratings. We focus on characteristics and data that our experience tells us are the most effective and reliable in the SPD evaluation process.

Data We Focus On: Power SPDs

Power SPDs include hardwired panel (type 1-2), individual equipment (type 2CA) and plug-in (type 3) devices.

Peak Surge Current

This is determined by the highest single shot a SPD can withstand without failure or degradation. This will vary per device type usually depending on it's intended install location (C,B,A). This rating will also very depending on device design. The higher the rating, the more robust the device.

MCOV

MCOV or Maximum Continuous Operating Voltage is the maximum voltage allowable before the device begins to operate (clamp). Typically, this is 15-25% above nominal system voltage. We don't recommend MCOV being less then 15%.

VPR

VPR or Voltage Protective Rating is a byproduct of the UL 1449 Safety Standard. The byproduct of the test are let-through voltage (limiting voltage) scores. These resulting scores are then placed into a range of predetermined values in the VPR Table (330 volts, 400 volts, 500 volts, 600 volts etc.).

Let-Through Voltage

Let-Through Voltage is remnant voltage passed from a SPD into the electrical system after a surge event. VPR provides a general range of what that voltage might be. The VPR range does not provide a true performance score. SPDs that provide Measured Limiting Voltage test results, conducted by independent test labs, using industry standard protocols reveal a more accurate score. 

Example:

  • Let-Through Voltage/Limiting Voltage result = 270 volts: Listed VPR = 330
  • Let-Through Voltage/Limiting Voltage result = 325 volts: Listed VPR = 330
  • Let-Through Voltage/Limiting Voltage result = 331 volts: Listed VPR = 400

SCCR

SCCR or Short Circuit Current Rating is the amount of available current that the SPD can be subjected to and safely disconnect from the power source under short circuit conditions. This rating can vary between devices and device types. The highest SCCR is 200 kAIC.

Modes of Protection

A mode is a distinct pair of wires protected by a SPD. Modes are classified as either Normal or Common.

  • Normal Mode: Phase to Neutral and Phase to Phase
  • Common Mode: Phase to Ground and Neutral to Ground

Many SPDs in the market place share components between modes as a protection design. This reduces performance, reliability and durability when compared to True All-Mode methodology. However, the trick is determining True All-Mode from Reduced Mode when both are advertised as "All-Mode."

Filtration Technology

In addition to Voltage Responsive Technology, some SPDs offer a form of Filtration Technology to improve performance and protection capabilities. These filtration options can differ. The Filtration Technology we focus on is:

Frequency Responsive designs (SineWave Tracking) is not EMI/RFI Filtration. FRCTM technology is designed to react to changes in frequency. This specialized circuitry protects against RingWave Surges.

Like Voltage Responsive Technology, Frequency Responsive CircuitryTM or SineWave Tracking Technology will vary in quality and performance. This will be determined by manufacturer and by SPD design.

Fusing-Circuit Interrupt

Fusing or Circuit Interrupt capabilities of SPDs can vary by manufacturer. Different technologies and designs are used to address SPD operational safety concerns. Component Level Thermal Fusing and Internal Over Current Fusing are two options. This fusing combination delivers redundant safety measures and doesn't require any mechanical operation to perform properly.

Safety Certifications

Safety Certifications are not required. However, they are beneficial and many engineers, associations and trade groups may not use a SPD without a Certification Marking/Seal. Safety Testing Organizations include UL, CSA, ETL and others.

Underwriters Laboratories (UL) is the most common in the United States. CSA, ETL and other safety certification organizations provide the same test requirements as UL. In the United States, all testing organizations fall under OSHA.

SPD Warranty

Reviewing the product Warranty can be a good way to help validate marketing materials and surge protector performance claims. However, it's important to read through the Warranty and understand what it actually provides for.

A Warranty should be straight forward and easily enforceable. It should cover manufacturing defects and operational failures incurred during the warranty period. Many SPD warranties only cover manufacturing defects.

Data We Focus On: Data Line & Telecom SPDs

High Quality, High Performance Data Surge Protectors and Telephone Line Surge Protectors

Data and Telecom include; telephone line, T1, coaxial, Ethernet (Cat5+) and others.

  • Peak Surge Current
  • MCOV
  • Modes of Protection
  • Let-Through Voltage
  • Certifications
  • Warranty

For additional information or to inquire about having a SPD tested to verify marketing data... please contact us.

The Right Surge Protector
The Right Surge Protector Ratings

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