"This outline of investigation covers LED (light emitting diode) kits intended for field installation to retrofit signs already installed in the field and LED kits intended for installation in new signs. Retrofit kits These LED kits are intended to replace all of the electrical components related to a type of illumination in a sign. For neon signs these components include neon tubes@ tube supports@ neon supplies@ and all secondary wiring from the neon supply. For fluorescent signs these components include fluorescent tubes@ lampholders@ ballast@ and ballast secondary wiring. All types of illumination within a sign must be replaced@ unless there are different compartments of a sign for different light sources and they only share the same circuitry at the branch circuit connection point. Retrofit kits include the power supply or transformer@ power supply or transformer enclosure@ the LEDs and the LED mounting means. New Sign Construction Component power units may be incomplete with respect to electrical enclosure@ mounting@ supply connections@ etc. LEDs@ secondary wiring@ and LED transformers or supplies may be provided separately. Glossary CLASS 2 CIRCUIT ?C The wiring@ conductors and components connected only to a Class 2 supply source. See Class 2 Supply Source@ 1.4.2. CLASS 2 SUPPLY SOURCE ?C An electrical source@ such as a transformer@ power supply@ or battery@ having an open-circuit voltage that is less than 30 V rms (42.4 V peak) or 60 V DC and having limited energy available in the circuit under load conditions@ including short-circuit and extremely low resistance. A Class 2 supply source can be either inherently limited or non-inherently limited. a) INHERENTLY LIMITED SUPPLY SOURCE ?C A transformer@ power supply or battery having no discrete protective device that is relied upon to limit the output energy available from the supply. A power supply or battery with internal current and energy limiting circuitry shown to be reliable is eligible to be identified as inherently limited. Transformers@ power supplies and batteries may be provided with protective devices as long as they are not relied upon to limit the output. b) NON-INHERENTLY LIMITED SUPPLY SOURCE ?C A transformer@ power supply or battery having a discrete protective device that automatically interrupts the output when the current and energy output reaches a prescribed limit. CONDITIONS OF USE ?C Parameters and specifications that identify the proper use of a component according to the requirements to which it has been determined to comply@ and limitations of the use of the component in a sign or outline lighting. DAMP LOCATION ?C The designation for a component that has been evaluated generally for use in exterior locations where protected overhead from rain and snow@ or interior locations where subject to moderate degrees of moisture@ primarily by humidity and condensation. Protected overhead is generally considered to be within an area formed by an imaginary line drawn from the outer edge of the eave@ overhang@ or signbody inward at a 45 degree angle from vertical. Additionally@ the interior of a sign body provided with a sign face and installed in an outdoor exposed location is a damp location. Examples include partially protected areas such as under a canopy@ under a roofed porch@ or indoors in a car wash away from a direct water spray. DRY LOCATION ?C The designation for a component that has been evaluated for use in an environment where the component is not normally subject to dampness or wetness. Examples include inside an indoor shopping mall@ inside a retail store@ in an attic or scuttle@ and other similar places. ELV CIRCUIT ?C A secondary circuit with limited voltage and energy that reduces the risk of fire and shock in accordance with the requirements in the Standard for Information Technology Equipment@ UL 60950. HAZARDOUS ENERGY LEVEL ?C A stored energy level of 20 J or more@ or an available continuous power level of 240 VA or more@ at a potential of 2 V or more. LPS-LIMITED POWER SOURCE ?C Power supplies identified as ""LPS"" or where the output is considered limited power@ are considered equivalent to power supplies with Class 2 outputs. POLLUTION DEGREES: a) POLLUTION DEGREE 2 ?C Normally only non-conductive pollution. However@ temporary conductivity is capable of being caused by condensation. b) POLLUTION DEGREE 3 ?C Conductive pollution@ or dry@ non-conductive pollution that becomes conductive due to condensation. SAFETY EXTRA-LOW VOLTAGE (SELV) CIRCUIT ?C A secondary circuit with limited voltage and energy that reduces the risk of fire and shock in accordance with the requirements in the Standard for Information Technology Equipment@ UL 60950. WEATHERPROOF ?C See Wet Location@ 1.4.10. WET LOCATION ?C The designation of a component that has been evaluated for use in a location that is subject to a direct spray or splashing of water or other liquids. Examples include locations used for outdoor channel letters and outline lighting or indoors in a car washing area in a direct water spray."
UL SUBJECT 879A-2006 history
2016UL Subject 879A-2016 Standard for LED Sign and Sign Retrofit Kits (CSDS Proposal, 5/27/2016)