UL-2353:2016 pdf free download – STANDARD FOR SAFETY Single- and Multi-L ayer Insulated Winding Wire.
5.1.3 All layers of insulation are not required to be made from the same material.
5.1.4 For spirally wrapped insulation that is constructed such that the creepage and clearance distances between layers, as wrapped, are less than those provided in the minimum creepage and clearance distances for Pollution Degree 1, of the Standard for Information Technology Equipment — Safety — Part 1: General Requirements, UL 60950-1, or the Standard for Medical Electrical Equipment, Part 1: General Requirements for Safety, UL 60601-1. The path between layers shall be sealed as for a cemented joint, and tested in accordance with the requirements for spacings filled by the insulation compounds as specified in UL 60950-1 and UL 60601-1. The test voltages for the electric strength tests are to be increased to 1.6 times their normal values.
5.1.5 One layer of material wound for spirally wrapped insulation with more than 50% overlap is considered to constitute two layers.
5.1.6 Solvent based enamel insulation used to coat the conductor is not to be counted as a layer when determining basic, supplementary and reinforced insulation.
5.2 Fully insulated wire (FIW)
5.2.1 For FIW the following layer thickness requirements apply:
a) A minimum increase of diameter due to insulation of 0.001 mm (0.00004 in) and a diameter range of 0.040 — 0.16 mm (0.0016 — 0.0063 in); or
b) A minimum increase of diameter due to insulation of 0.002 mm (0.00008 in) and a diameter range greater than 0.16— 1.60 mm (0.0063 — 0.063 in).
5.2.2 The manufacturer must declare the type of insulation they are producing and also indicate the number of layers that will make up their insulation, i.e. basic, supplementary or reinforced. For example, a manufacturer may declare that their 0.60 mm conductor coated with 50 layers (each layer a minimum of 0.001 mm) of insulation will be considered their supplementary insulation.
6 Thickness of Insulation
6.1 The average thickness of insulation is to be determined by means of one of the following methods: See 6.3.
a) Use of a machinist’s micrometer caliper. The caliper is to have flat surfaces on the anvil and on the end of the spindle and is to be calibrated to read directly to at least 0.001 mm or 0.0001 in.
b) Use of a dead-weight dial micrometer. The micrometer is to be capable of exerting the
forces indicated in 6.5(a) and (b) onto a sample through a flat, rectangular presser foot 1.98 by 9.52 mm or 0.078 by 0.375 in. The anvil of the instrument is to be of the same dimensions as
the presser foot.
c) A microscope or other optical instrument calibrated to read directly to at least 0.001 mm or 0.0001 in is to be used to measure the maximum thickness of each insulation layer, conductor diameter and overall wire diameter.