Surge Protection Devices Guide

November 20, 2020

 

Surge Protection Devices Guide

If you work in communications and distribution networks, then you are already well aware of the importance of Surge Protection Devices (SPD) in maintaining the functionality of your systems.

They are commonly used for power electric supply networks, distribution and communication networks, but did you know that they are also valuable in lighting systems?

You have made the investment on energy efficient LED lighting… Now is the time to ensure that you protect that investment to the best level! Time to ensure you have SURGE PROTECTION on the panel that is supplying those LED fixtures! LED fixtures utilize electronics that are susceptible to SURGE. Installing Surge protection at the distribution panel can reduce these surges and any potential damage that may occur.

What are Surge Protection Devices (SPD)?

Surge Protection Devices (SPD) are electrical components used for voltage protection in power supply circuits and electrical distribution networks. When there is an increase in voltage above the average level, surge protectors redirect the electricity flow away from your devices, preventing equipment damage and downtime.

  • Surge Protection Devices also protect Residential Homes

Mersen’s Surge-Trap® STXH surge protective device adds a critical layer of surge protection for your entire home. From your family room to your office, and your kitchen, your entire electrical system is protected. This simple whole house solution is installed at your load center – out of sight, out of mind.

Featuring Mersen’s industry leading TPMOV® Technology inside, Mersen’s Surge-Trap® SPDs meet the rigorous safety requirements of the UL 1449 4th edition safety standard and need no additional overcurrent protection.

 

 

PD Term Definitions

  • Nominal system voltage

    The voltage assigned to a system during regular operation. The surge protector device should match this nominal system voltage.

 

  • MCOV

    The Maximum Continuous Operating Voltage, this is the maximum voltage the device can withstand before conduction (clamping) begins. It is typically 15-25% higher than the nominal system voltage.

 

  • VPR

    Voltage Protection Rating. VPR limits the voltage that passes through the SPD during a surge. A lower VPR will protect your devices better. VPR is a clamping voltage measurement that is rounded up to one of a standardized table of values. The standard VPR ratings include 330, 400, 500, 600, 700, etc. As a standardized rating system, VPR allows the direct comparison between like SPDs (i.e. same Type and Voltage).

 

  • Nominal Discharge Current (In)

    It allows an SPD to resist and function at a peak value of current without damage after repetitive surges (15 total surges). The manufacturer selects the peak value from a predefined level (3kA, 5kA, 10kA, or 20kA) UL has set. This value is used to test the product, having the SPD subject to 15 surges at the chosen curret, 1 minute apart, with rated voltage applied between surges.

 

  • SCCR

    Short Circuit Current Rating. It is the maximum current an SPD can withstand during a short circuit, allowing to safely disconnect from the power source, without jeopardizing the equipment.

 

How to Select The Right Surge Protection Device

To select a SPD, there are several considerations to take into account. Here are some advice that will guide you in your search for an SPD.

1. Average design lifespan of electrical equipment should be roughly 30 years, thus SPD selection should fall within this design parameter.

2. Identify what you are trying to protect and the value of the equipment. This will give you an understanding of the level of protection your equipment needs.

3. Locate where the device will be installed. Knowing the location will help you identify the type of SPD needed: Type 1 (service entrance), Type 2 (sub panel), or Type 3 (point of use)

4. Make sure the device has outlets for all your equipment and displays the UL 1449 (safety standards for every SPD) on the box.

 

Regarding performance ratings, don’t forget to:

1. Specify the appropriate SPD with the highest Nominal Discharge current rating available (i.e., 10kA or 20kA)

2. Specify the appropriate SPD with the highest Peak Surge current rating. This is provided by the SPD manufacturer. The higher the number, the higher longevity SPD has.

3. Specify the appropriate SPD with a high Short Circuit Current rating to match the system’s available short circuit current level

4. Specify the appropriate SPD with Maximum Continuous Operating Voltage, higher than normal voltage fluctuations. This way, it does not exceed the MCOV rating of the SPD. (i.e. 120V system = 150VMCOV)

Why Nominal Discharge Current (In) Matters

If Surge protection devices are OVERVOLTAGE protection . . . then why need to look at Nominal Discharge Current (In) ratings of SPD ?

In UL 1449 3rd edition, it was determined that ALL SPD manufacturers have their product tested to prove performance characteristics. In order to provide standard testing, Nominal Discharge Current (In) rating was chosen for a measure of how robust or rugged an SPD performs. While the SPD is an OVERVOLTAGE protection device, the I2t (discharge energy) that the SPD can handle safely without damage is selected by the manufacturer for the test. Typically Type 1 = 10kA or 20kA, Type 2 = 3kA, 5kA, 10kA or 20kA.

When selecting or specifying an SPD, looking at all other performance characteristics, one should select/specify an SPD with highest Nominal Discharge Current (In) rating. This will provide the greatest degree of longevity for the SPD (based on ACTUAL test results).

Looking at I2t :

  • 10kA (In) rated SPD will ONLY take 25% of energy that a 20kA (In) rated SPD will handle
  • 5kA (In) rated SPD will ONLY take 6.25% of energy that a 20kA (In) rated SPD will handle
  • 3kA (In) rated SPD will ONLY take 2.25% of energy that a 20kA (In) rated SPD will handle

 

Peak Surge Current rating is a measure of how large, or expected longevity of an SPD is, as given by the manufacturer. Peak Surge Current is NOT a UL 1449, 3rd edition, tested parameter. Rather it is information that each manufacturer determines for their given product.

 

Mersen Surge Protection Devices in Stock at E.B. Horsman & Son

Did you know? 80% of surges occur WITHIN your own facility! Utilizing a Mersen Surge Protective Device on your electrical distribution panel ensures a high degree of surge protection!

Features:

  • ✓ LED indicator to show when protected!
  • ✓ Easy Installation
  • ✓ TPMOV technology ensures a high level of SURGE protection for minimal investment

 

Mersen Surge Protection Devices in Stock at E.B. Horsman & Son

Did you know? 80% of surges occur WITHIN your own facility! Utilizing a Mersen Surge Protective Device on your electrical distribution panel ensures a high degree of surge protection!

Features:

  • ✓ LED indicator to show when protected!
  • ✓ Easy Installation
  • ✓ TPMOV technology ensures high level of SURGE protection for minimal investment
ApplicationProductPart #DescriptionUPC Code
Residential, Commercial & IndustrialType 1, Indoor Application – STXH productSTXH240S05

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120/240volt, split phase782001472504
Commercial/IndustrialType 1, Indoor Applications – STXH,STXR productSTXH240S05

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120/240volt, split phase782001472504
STXR208Y05

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120/208volt, 3ph Y782001469955
STXR208Y05N

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347/600volt, 3ph, N-G78200146996
STXR600Y05

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347/600volt, 3ph, Y782001469993
Mounting BracketSTXRMBK

Buy

78200147076
Industrial (Control Panels)/CommercialDin Rail, Pluggable Style – STP productSTP120P07M

Buy

120volt, 1pole0782001477684
STP240S07M

Buy

120/240volt, split phase0782001477752

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