UL-879A:2012 pdf free download – STANDARD FOR SAFETY LED Sign and Sign Retrofit Kits.
8 Supply Connections
8.1 Knockouts for trade size 1/2 fittings shall be provided when fittings or bushings are not provided for field supply connections. Knockouts shall withstand a 10-lb knockout test as specified in the Standard for Luminaires, UL 1598.
8.2 Secondary connections may be pig-tail leads a minimum 1.5-rn (5-fl) long, 152.4-mm (6-in) long pigtail leads within a wiring compartment, or a terminal connector. A terminal connector for connection to Class 2 output circuits is not required to be enclosed.
9 Separation of Circuits
9.1 Secondary circuit wiring shall be insulated for the maximum voltage involved or completely and permanently separated from the wiring of other than secondary circuits or Class 2 circuits.
10 Over-Current Protective Devices
10.1 An over-current protective device shall not be connected in the neutral (grounded) conductor unless
the device simultaneously interrupts the grounded and ungrounded supply conductors.
11 Fuses
11 .1 Fuses shall be inaccessible by being located completely within an electrical enclosure unless the fuseholder is of the type that will prevent insertion of a higher current rated fuse.
11 .2 Where a fuse is provided, it shall be mounted in a fuseholder of the proper type and rating, or be soldered by pigtail style leads directly to a printed wiring board or be mounted using surface mount technology.
11 .3 The fuse type identification and ampere rating shall be marked on or adjacent to the fuse and fuseholder. See Required Markings, Section 24, for wording.
12 Circuit Breaker or Supplementary Protector
12.1 A supplementary protector or circuit breaker connected in the supply circuit shall open all ungrounded conductors.
12.2 For a vertically mounted circuit breaker or supplementary protector, the down position shall be the off position.
13 Thermal Protective Devices
13.1 A thermal protective device relied on to comply with the performance requirements of this standard shall:
a) Comply with the requirements of other appropriate standards listed in Appendix A of this standard as appropriate for the type of thermal protective device used; and
b) Be located where it is capable of being either mechanically secured or physically trapped so as to be subject to consistent heat sensing.
14 Thermistors
14.1 A thermistor, Positive Temperature Coefficient (PTC) or Negative Temperature Coefficient (NTC) resistance, provided to limit the output of a unit to within the required current or power levels, or with maximum temperature requirements or otherwise used to obtain acceptable test results shall comply with the requirements of other appropriate standards listed in Appendix A of this standard and shall have a Calibration Class of Cl or Ca
15 LED Units or Modules
15.1 General
15.1.1 These requirements apply only to the LED displays provided as either a panel or module for use in a sign.
15.1.2 Tubular LED lamps that are intended to replace fluorescent lamps and use existing lampholders only for mechanical support and are powered by separate supply connections shall comply with:
a) The requirements for tubular lamps in the Standard for SeIf-Ballasted Lamps and Lamp Adapters, UL 1993.