UL 8750-2015 pdf download
UL 8750-2015 pdf download.Light Emitting Diode (LED) Equipment for Use in Lighting Products.
7.11 Coil insulation
7.11.1 General
7.11.1.1 A coil shall be provided with insulation between the coil and any dead-metal part, and between each adjacent pair of windings. Physical insulation material is not required if the spacings requirements of electrical spacings of 7.8 are met without any insulation material In place.
Exception No. 1: Two or more secondary windings may be considered as a single winding and interposing insulation is not required if, when interconnected, the windings comply with the performance requirements for a single winding.
Exception No. 2: Insulated wiring which complies with the Standard for Single- and Multi-Layer Insulated Winding Wire, UL 2353, is considered suitable insulation between the coil and any dead-metal part.
7.11 1,1 rised Novembr 1.2011
7.11.1.2 Coil insulation shall either be inherently moisture resistant or treated to render it moisture resistant. Film-coated magnet wire is considered to be moisture resistant.
7.11.2 Insulation for transformers
7.11.2.1 Insulation between uninsulated, primary wires of opposite polarity shall be one of the following:
a) Electrical grade paper, waxed or otherwise treated to resist the absorption of moisture, having a total thickness of not less than 0.3 mm (0.01 in),
b) Other insulating material having a dielectric breakdown strength of not less than 2500 V in the thickness used as determined by the tests on insulating materials specified in the Standard for Class 2 Power Units, UL 1310, or
C) Insulated wiring which complies with the Standard for Single- and Multi-Layer Insulated Winding Wire. UL 2353.
7.11.2.1 rvised Novemb.r 1, 2011
7.11.2.2 Insulation between primary and secondary windings shall be one of the following:
a) Electrical grade paper, waxed or otherwise treated to resist the absorption of moisture, having a total minimum thickness of 0.3 mm (0.01 in).
b) A molded polymeric material such as a coil form or bobbin having a minimum thickness of 0.65 mm (0.03 in),
c) Other than a molded polymeric material and having a dielectric breakdown strength of not less than 2500 V in the thickness used as determined by the tests on insulating rnatenals specified in the Standard for Class 2 Power Units, UL 1310, or
d) Insulated wiring which complies with the Standard for Single- and Multi-Layer Insulated Windin9 Wire, UL 2353.
7.11.2.3 Tape used as insulation in lieu of spacings for a concentrically-wound bobbin transformer shall provide a continuous 0.8-mm (1/32-in) minimum wide bent up edge against the bobbin flanges.
711.2.3 revised November 1.2011
7.11.2.4 A conceritncally-wounci bobbin transformer shall be subjected to the output loading test requirements of 8.5.3. The test shall be continued for 15 days if the transformer has:
a) The primary winding wound over the secondary winding or the secondary winding wound over the primary winding, and
b) The primary winding insuLated from the secondary winding by a layer of insulating material other than that specified In 7.11.2.1(b).
Exception: The test is not required to be applied for 15 days if the following requirements are met:
a) Multiple layered winding wire is used, which has been evaluated to the requirements for miscellaneous insulating devices and materials of the Standard for Polymeric Materials — Shod Term Property Evaluations, UL 746A. the Standard for Polymeric Materials — Long Term Property Evaluations. UL 7468, and the Standard for Polymeric Matenals — Use in Electrical Equipment Evaluations, UL 746C.
b) The primary-to-secondary winding spacings are reliably maintained and comply with Table
7.4,
C) The requirements in the Standard for Insulation Coordination Including Clearances and Creepage Distances for Electrical Equipment, UL 840, are reliably maintained for the primary-to- secondary creepage distance. arid a Comparative Tracking Index (CTI) rating of 100 for all insulating material is determined, os
d) Insulated wiring is used which complies with the Standard for Single- and Multi-Layer Insulated Winding Wire, UL 2353.
7.11.2.4 revised May 22. 2014
7.11.2.5 Insulation between the primary winding and the core shall be one of the following:
a) Electrical grade paper, waxed or otherwise treated to resist moisture, having a minimum total thickness of 0.3 mm (0.01 in),
b) A molded polymeric material such as a coil form or bobbin having a minimum thickness of 0.65 mm (0.03 in).
C) Other than a molded polymeric material and having a dielectric breakdown strength of not less than 2500 V in the thickness used as determined by the tests on insulating materials specified in the Standard for Class 2 Power Units, UL 1310.
