1 Scope

1.1 These requirements cover indoor fixed electric heating systems for use on system voltages not exceeding 600 V.

1.2 The heating systems covered by this Standard are intended for installation in accordance with the National Electrical Code, NFPA 70, Article 424.

1.3 These requirements cover the following electric heating systems:

1. a) Heating cable systems;

2. b) Heating mat systems;

3. c) Heating panel systems;

4. d) Modular flooring heating systems; and

5. e) Low voltage systems including power units.

6. With the following types of insulated heating elements:

7. f) Heating cable elements;

8. g) Laminate elements; and

9. h) Flat strip elements.

10. Of the following types:

11. i) Constant wattage elements;

12. j) Self-regulating elements; and

13. k) Low voltage elements.

1.4 These requirements cover electric heating systems permanently installed as follows:

1. a) WOOD SUBFLOORS – Installed above (on top of) or under (adjacent to rafters or joists);

2. b) CONCRETE SUBFLOORS – Installed above (on top of), inside (embedded), or under (in earth or sand bed);

3. c) CEILINGS – Installed inside (embedded), above (attic or between floors of a building adjacent to ceiling rafters or joists), or under (room side);

4. d) In WET LOCATIONS – Locations where the heating element may be subject to saturation with water after installation;

5. e) Embedded systems;

6. e) Underneath and in direct contact with floor coverings (non-embedded), while above wood or concrete subfloors;

7. f) Modular flooring heating systems installed above wood or concrete subfloors; and

8. g) Shower benches.

1.5 These requirements do not cover electric heating systems that are covered under the following standards:

1. a) Electrical Resistance Heat Tracing for Commercial and Industrial Applications, UL 515;

2. b) Movable and Wall- or Ceiling-Hung Electric Room Heaters, UL 1278;

3. c) Fixed and Location-Dedicated Electric Room Heaters, UL 2021; and

4. d) Electric Heating Appliances, UL 499.

Summary of Topics

This reaffirmation of ANSI/UL 2683 dated May 19, 2025 is being issued to update the title page to reflect the most recent designation as a Reaffirmed American National Standard (ANS). No technical changes have been made.