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:
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.
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 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 MCOVs less then 15%.
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 UL VPR Table (330 volts, 400 volts, 500 volts, 600 volts etc.).
Let-Through Voltage is remnant voltage passed from a SPD into the electrical system after a surge event. VPR provides a general range of where that voltage might be around. The VPR range does not provide a true performance score. SPDs that provide Measured Limiting Voltage (MLV) test results, conducted by UL-CSA certified test labs reveal more accurate Performance Data.
The MLV data helps determine a SPDs real world (installed) performance capability. This is one piece of information based solely on the units protection quality. Not all manufactures provide this performance data.
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.
A mode is a distinct pair of wires protected by a SPD. Modes are classified as either Normal or Common.
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."
In addition to Standard Clamp or Voltage Responsive Technology, some SPDs offer different forms 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) are not EMI/RFI Filtration. FRCTM technology is an advanced design that reacts to changes in frequency. This specialized circuitry protects against RingWave Surges.
Like Standard Clamp or Voltage Responsive Technology, Frequency Responsive CircuitryTM (SineWave Tracking) Technology will vary in quality and performance. This will be determined by manufacturer and by SPD design.
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 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.
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.
For additional information or to inquire about having a SPD tested to verify marketing data... please contact us.
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