Led Design Guide Page 14 LED Design Guide

LED Lighting Design Guide 2015 Littelfuse LED Lighting Design Guide www.littelfuse.com LED luminaires today are over two times the cost of the incumbent HPS lighting assemblies. However, LEDs are expected to last nearly 100,000 hours - about three to four times that of HPS luminaires, while consuming 80% less energy. The US has established uniform performance and safety standards for Outdoor lighting including roadway, parking lot and garage illumination. UL 1598 is the Standard for Safety of Luminaires which garners compliance from a majority of outdoor lighting manufacturers in N. America. This specification covers requirements for overcurrent protective devices such as fuses that are used for overload and short circuit protection in luminaires. These requirements are similar to those in UL 60950. In addition, UL 8750 - the Standard for LED Equipment for use in Lighting Products also calls out the use of overcurrent protective devices such as fuses. The US Department of Energy's (DOE) Municipal Solid-State Street Lighting Consortium (MSSSLC) has released a model specification for LED roadway luminaries for use by cities and municipalities when specifying LED lighting requirements. This DOE specification is projected to become an ANSI/NEMA C136.x requirement in the near future. The DOE's goal is to protect LED luminaire investments by establishing strong safety and surge standards, so light fixtures will require minimal maintenance and are able to last a minimum of five years without service disruption. These will be important characteristics as cities and municipalities begin lighting replacement and retrofit programs, which will involve large capital investments. To support this initiative, funding and subsidy programs such as the American Recovery and Reinvestment Act (ARRA) are helping many cities reduce the initial cost of these LED lighting projects The DOE specification details performance, safety and surge immunity requirements. Excerpts from this specification are listed in Table 4 and Table 5. Table 4. DOE MSSSLC 1.2/50s Combination Wave Test Specification Parameter Test Level/ Configuration 1.2/50s Open Circuit Voltage Peak Low: 6 kV. High: 10kV* 8/20s Short Circuit Current Peak Low: 3 kA. High: 10kA Coupling Modes L1 toPE, L2 to PE, L1 to 72 Polarity and Phase Angle Positive at 90 and Negative at 270 Test Strikes 5 for each Coupling Mode and Polarity/Phase Angle combination Time Between Strikes 1 minute Total Number of Strikes = 5 strikes 3 coupling modes 2 polarity/phase angles = 30 totaI strikes *This is a MINIMUM requirement. Note that for most combination wave generators, which have a source impedance of 2 , the generator charging voltage will need to be raised above the specified level (to somewhere in the vicinity of 20kV) to obtain the specified current peak. LED Lighting Compliance with Global Standards (continued) 14

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