Outline of Investigation for Electric Heating Products For Installation Under Floor Coverings
1.1 These requirements cover fixed electric heating products for installation under floor coverings and above a subfloor, in accordance with the National Electrical Code, NFPA 70, Article 424, for use on system voltages not exceeding 600 V.
1.2 These requirements cover electric heating products of the type specified in 1.3, only when installed per 1.4.
1.3 These requirements cover the following product types:
a) Electric heating cables and cables on carriers;
b) Flexible and rigid electric heating panels, mats, and heating panel sets;
c) Electric flexible heating products, including carbon film-type constructions; and
d) Any combination of the above.
1.4 These requirements cover one or more of the following installation types:
a) Above a subfloor, the subfloor being constructed of wood, concrete, or other material;
b) Directly underneath a floor covering such as tile, carpet, wood, laminate, sheet vinyl, decorative concrete, or other floor covering;
c) Embedded in and covered with a layer of thinset, mortar, or the like under a floor covering;
d) Not embedded, and in direct contact with combustible or combustion resistant material subfloor or floor covering, except as noted in 1.7(j);
e) In dry or damp locations per the National Electrical Code, NFPA 70; and
f) Any combination of the above.
1.5 These requirements do not cover electric space, floor, or ceiling heating products that are fully addressed by individual requirements that are separate from this Outline, including:
a) Electric heating cables that are within the scope of the Standard for Electric Space Heating Cables, UL 1673; and
b) Electric heating panels and heating panel sets that are within the scope of the Standard for Electric Heating Panels and Heating Panel Sets, UL 1693.
1.6 These requirements do not cover electric heating products that are covered by individual requirements that are separate from this Outline. Other related standards include:
a) Electrical Resistance Heat Tracing for Commercial and Industrial Applications, UL 515;
b) Movable and Wall- or Ceiling-Hung Electric Room Heaters, UL 1278;
c) Outline of Investigation for Mobile Home Pipe Heating Cables, UL 1462;
d) Outline of Investigation for Roof and Gutter De-Icing Cable Units, UL 1588;
e) Outline of Investigation for Residential Pipe Heating Cables, UL 2049;
f) Fixed and Location-Dedicated Electric Room Heaters, UL 2021; and
g) Electric Heating Appliances, UL 499.
1.7 These requirements do not cover the following:
a) Heating products connected to the supply by use of a flexible cord with attachment plug;
b) Heating products that are movable after installation;
c) Heating products with integral means of producing air flow;
d) Heating products manufactured and sold as an integral part of a floor covering materials such as heated floor tiles, heated carpet, and heated laminate floor;
e) Heating products intended for use outdoors;
f) Heating products intended for installation on, in, or above a ceiling;
g) Heating products intended for installation in or under a concrete subfloor;
h) Heating products intended for installation under a wood subfloor;
i) Heating products employing self-regulating or positive temperature coefficient (PTC) heater design; and
j) Flexible film-type products not embedded, and installed directly in contact with rigid or flexible floor coverings.
1.8 These requirements do not cover additional grounding or shielding that may be required during installation in accordance with local or national codes.
1.9 These requirements do not cover switches, transformers, power supplies, controls (i.e. temperature) or protective devices (i.e. ground fault protection) that are installed separate from the heating equipment as part of the complete heating system installation, unless inherent to the heating product. Those devices are covered by individual requirements that are separate from this Outline.