UL 1449 has undergone extensive revision as surge protection’s standard for safety. UL 1449 Third Edition, defines performance testing and nomenclature, which effectively reboots the surge protection industry. UL 1449’s performance testing provides a way to compare newly evaluated Surge Protective Devices (SPDs), formerly known as Transient Voltage Surge Suppressors (TVSS). These changes became effective September 29, 2009, which predictably impacts specifiers and the supply chain as follows:

• New performance tests use more surge current, resulting in increased clamping voltages

• New test results are numerically higher, thus not meeting old-style specifications 

• Electrical & General Contractors and Distributors might waste time trying to source surge protectors that cannot meet an out-dated specification 

• In frustration, Old/Obsolete TVSS may be sumitted, which may or may not be UL Listed, or supported in the future

• Specifying Engineers might waste time evaluating submittals

• Specifying Engineers may not be getting what they want, or what they think they’re getting

Terminology Shift and Inclusion of Surge Arresters:

The term Transient Voltage Surge Suppressor (TVSS) is replaced by Surge Protective Device (SPD). This nomenclature change coincides with NEC and International standards’ terminology. Surge Protective Device is a more general description and pulls oldstyle secondary surge arresters (SSAs) aka lightning arrestors under UL’s Surge Protective Device performance and safety standard. Type 1 Surge Protective Devices replace almost every secondary surge arrester on the market effectively obsolescing them.

Clamp Voltage Test Change: 

Old 2nd Edition UL tests used 500A, 6,000V. New 3rd Edition UL tests use 3,000A, 6,000V, i.e. 6 times more surge current. The Voltage Protection Rating (VPR) for a Surge Protective Device will be higher than the Suppressed Voltage Rating (SVR) of an identical surge protector. Higher current levels equal higher clamp voltages.tandard

The change from Suppressed Voltage Rating (SVR) to Voltage Protection Rating (VPR) is probably the single most important change in UL 1449 3rd Edition relating to specifiers. The SVR listed in current specifications will be obsolete. Comparing a VPR rating to a SVR rating would provide no information of value. In order to make accurate performance comparisons, the Voltage Protection Rating (VPR) of one device must be compared with the VPR of another device.

UL96A Lightning Protection Master Label Impact:

Previously, UL 96A required surge protectors evaluated as secondary surge arresters. There were issues associated with different regulation and administration. Secondary surge arresters now evolve into Type 1 Surge Protective Devices, and UL 96A will accept Type 1 or Type 2 SPDs having 20kA In ratings (new rating, explanation follows).

Type Designations:

UL 1449 3rd Edition assigns type designations to Surge Protective Devices (1, 2, 3, 4) based on the installation location within the electrical distribution system.

Type 1 – Installed on line or load side of the Main Overcurrent Protection (OCP), similar to what you knew as Secondary Surge Arrestors, except now includes rigorous safety testing. Includes all OCP & safety disconnectors inside the Surge Protective Device.

Type 2 – Installed on load side of the Main OCP, similar to what you know as hardwired Transient Voltage Surge Suppressors (TVSS), and it may require external OCP.

Type 3 – Point of Utilization, direct plug in type devices, similar to what you know as surge strips (i.e. power bars) Theses devices are intended for installation 10 meters from the panel (rational based on IEEE Cat. A location).

Type 4 – Surge suppression components, could be a basic component or a complete module. Type 4 components can be tested for Type 1, Type 2 or Type 3 applications.

Nominal Discharge Current Test (In):

The In test is new to UL 1449. It originates from IEC style testing whereby a Surge Protective Device must remain functional after being subjected to 15 repetitive impulses of a specific value. Every mode of protection is tested, including any required overcurrent protection. Between impulses, the Surge Protective Device is energized at Maximum Continuing Operating Voltage (MCOV). The test format tends to cause heat accumulation, which makes this much more difficult than face value suggests. Type 1’s are to be tested at 10kA or 20kA, Type 2’s to 3kA, 5kA, 10kA, or 20kA.

The testing is performed in conjunction with VPR tests. For more information on the prescribed UL test set up and test outline please download our UL 1449 Third Edition Engineering Bulletin at: www.aptspd.com/ul_default.aspx

Conclusion:

Understanding the major revisions in UL 1449 3rd Edition is important for specifiers as this revision will render your 2nd Edition specifications obsolete. New 3rd Edition products will not meet old style specs, wasting time and money. You can download APT’s guide specifications at www.aptspd.com/ul_guidespecs.aspx. If you would like additional free training, please visit our training page, www.aptspd.com/training.aspx

For any other questions or concerns please contact APT directly.