Alltec Recognizes UL 3rd Edition Changes to Surge Protection Devices

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Alltec Corporation recognizes ANSI/UL 1449 & UL Standards for Safety for Surge Protective Devices. This will mean differences in classification, testing, and terminology for SPDs (formerly known as Transient Voltage Surge Suppression devices, or TVSS). Alltec designs and manufactures the PowerTrip® line of Surge Protection Devices.

September is a time for change. Mornings become brisk as summer weather fades, while leaves start to inspire color patterns across mountainous landscapes. For Alltec Corporation September will propel changes to the PowerTrip® line of surge protection devices. These improvements comply with future requirements for UL 1449. Officially, it will be the 3rd Edition to UL 1449 with a fresh title of "ANSI/UL 1449 & UL Standard for Safety for Surge Protective Devices, UL 1449." As the name signifies, safety is the reason for these updates, and Alltec remains at the forefront of the power quality industry while pioneering these advances.

With these new additions there will be differences in classification, testing, and terminology that all parties involved will need to fully understand. For example:

  •     The term Surge Protective Device (SPD) now covers what was referred to as Secondary Surge Arrestors and traditional Transient Voltage Surge Suppression devices and components.
  • UL 1449 3rd Edition now applies to devices used to repeatedly limit transient voltages on 50/60 Hz circuits 1000 volts and below.
  • Testing has been revised to include Nominal Discharge Current (In).

Furthermore, 4 classifications or types of SPDs have been established, depending on where in the electrical system the device is connected. When determining which type of classification of SPD to use, the location and application are the determining factors. In addition, peak surge current, voltage or frequency responsive circuitry requirements, operating voltage and wiring, enclosure and needed options are still required for proper selection.

SPD Type 1: Permanently connected SPDs installed on the line side just after the meter. This type closely relates to the devices previously referred to as secondary surge arrestors. These Type 1 SPDs must be especially powerful to conduct the high energy impulse of a lightning strike event. In order for a lightning protection system to receive an UL96A Master Label, a Type 1 20kA Nominal Discharge Current rated unit should be specified.

SPD Type 2: Permanently connected SPD installed on the load side of the service panel. This type most closely relates to devices that were previously classified as Transient Voltage Surge Suppression (TVSS). These applications include the PowerTrip® panel and branch panel units. Type 2 SPDs can be offered in a standard 10kA or an optional 20kA Nominal Discharge Current (In).

SPD Type 3: Point of use SPDs, installed at a minimum conductor length of 10 meters (30 feet) from the electrical service panel to the point of use, for example cord connected, direct plug-in, receptacle type and SPDs installed at the equipment being protected. These SPDs can also be tested as Type 2 devices, thus eliminating the 10 meter rule.

SPD Type 4: Component SPDs and component assemblies.

With UL 1449 3rd Edition, latest testing guidelines were established and innovative terms introduced. Nominal Discharge Current (In) and the duty cycle test are new to UL 1449. The testing process is lengthy and is used to verify that an SPD can withstand exposure to the declared (In) without degradation. Different SPD Types have special (In) requirements. The Nominal Discharge Current value, set by the manufacture, can be either 10 kA or 20 kA for a Type 1 SPD or 3 kA , 5 kA, 10 kA or 20 kA for Type 2 SPDs. The testing current is applied in three groups of 5 pulses each. Between impulses the SPD is energized at the unit's MCOV (Maximum Continuous Operating Voltage) rating. The previous version of UL 1449 used 500A testing labeled as Suppressed Voltage Ratings ( SVR ). The latest test uses 3,000A impulses and labels the results as Voltage Protection Ratings (VPR). Higher current levels result in higher limiting voltages, therefore the VPR ratings will be higher numerically than the SVR rating. Care must be taken when evaluating different units to make sure the VPR ratings for both units are being compared correctly.

The PowerTrip® line of SPDs will continue to offer a complete array of products that present the highest level of protection while maintaining the industry's best warranty. PowerTrip® Surge Protection Devices incorporate "Frequency Responsive Circuitry" technology years ahead of any other devices on the market today. Utilizing proprietary electro-chemical encapsulation, PowerTrip® SPDs dissipate large amounts of surge energy to prolong service life. Some major features include:

  •     Discrete "All Mode" circuitry
  •     Industry leading Let-Through voltage performance
  •     25 Year free replacement warranty
  •     Frequency Responsive Circuitry
  •     Independent verification of performance and safety

The PowerTrip® catalog data sheets are currently being updated to reflect the new industry terminology and testing results. In addition, the latest master specification and application guides are being developed to address the 3rd Edition changes and to assist engineers, contractors and all end users with the selection process. For more information on Alltec's PowerTrip® Surge Protection Devices (SPDs) or UL 3rd Edition changes visit or contact us at pr(at)allteccorp(dot)com.


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Beth Chittum
Alltec Corporation
828.646.9290 ext. 41
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