Effective December 31, 2015

Standard Information
Standard Number:
UL 499
Standard Name:
Electric Heating Appliances
Standard Edition and Issue Date:
14th Edition Dated November 7, 2014
Date of Revisions:
November 7, 2014
Date of Previous Revisions to Standard:
13th Edition Revised February 11, 2013
Effective Date of New/Revised Requirements

Effective Date (see Schedule below): December 31, 2015

Impact, Overview, Fees and Action Required

Impact Statement: A review of all Listing Reports is necessary to determine which products comply with new/revised requirements and which products will require re-evaluation. NOTE: Effective immediately, this revised standard will be exclusively used for evaluation of new products unless the Applicant requests in writing that current requirements be used along with their understanding that their listings will be withdrawn on Effective Date noted above, unless the product is found to comply with new/revised requirements.

Overview of Changes (Specific details of new/revised requirements are found in table below):

  • Alternate Test Felt for Vivarium Heaters
  • Deleted X-Rays for Sheath Heaters
  • Revised Leakage Current Standard Reference
  • Added Requirements of Current Collectors for Instantaneous Water Heaters
  • Added Requirements of Temperature Limiting Means for Instantaneous Water Heaters

Schedule: So that shipping of products with Listing Marks will not be interrupted, an approximate schedule has been established to ensure Listing Reports are found compliant by Effective Date:

  • April 30, 2015 = 8 Month Report Review – Intertek will review all Reports. Update if compliance is verified or issue Findings Letter/Quote for any re-evaluations needed
  • June 30, 2015 = 6 Month Quote Cut-off – Quotes returned for necessary re-evaluations
  • November 30, 2015 = 30 Day Warning – Client advised of all non-compliant Reports to be Suspended
  • December 31, 2015 = Effective Date – ATM Suspended for all non-compliant Reports

Fees: An initial review of Listing Report (s) will be covered by a direct billing project and will be invoiced at not more than $1,000 per report.

Client Action Required:

Information – To assist our Engineer with review of your Listing Reports, please submit technical information in response to the new/revised paragraphs noted in the attached or explain why these new/revised requirements do not apply to your product (s).

Current Listings Not Active? – Please immediately identify any current Listing Reports or products that are no longer active and should be removed from our records. We will do this at no charge as long as Intertek is notified in writing prior to the review of your reports.

Description of New/Revised Technical Requirements

NOTE: Additions to existing requirements are underlined and deletions are shown lined out below.

15 Heating Elements

New clause added;

An instantaneous water heater with an open-wire element immersed in water shall additionally comply with the requirements of Sections 11, 27, 29 and 35. It shall not employ a power supply cord or plug.


New clause added;

Instantaneous water heaters shall be equipped with a temperature-limiting means in addition to its control thermostat to disconnect all ungrounded conductors. Such temperature-limiting means shall be installed to sense maximum water temperature and be a trip-free, manually reset type.

Exception: Instantaneous water heaters with a capacity of 4 liters or less that comply with all applicable requirements of this standard are not required to be provided with a temperature-limiting means.


New section added;

Leakage Current Collectors


An instantaneous water heater with an open-wire element immersed in water shall be provided with a leakage current collector that complies with 29.2 – 29.7 and Escape Current Test, Section 35.

Exception: A leakage current collector is not required if the open-wire heating element is isolated from the supply source.

29.2 A leakage current collector shall be provided at the water inlet and outlet. It shall be continuous metal piping, including the inlet / outlet, or may be discrete metal parts at the inlet / outlet.
29.3 Leakage current collectors shall be reliably bonded to the equipment grounding terminal of the appliance. A bonding conductor shall not be accessible to the user when the appliance is installed as intended.
29.4 A leakage current collector shall have a minimum length of five times its own inside diameter or the equivalent ratio of length to cross-section for non-circular configurations.
29.5 A leakage current collector shall be made of an unplated metal such as brass, stainless steel, or other equally corrosion-resistant metal that is intended to resist galvanic action in accordance with 29.6. Galvanized metal pipe is not considered to be sufficiently corrosion-resistant for use as a current collector. When copper alloy is used, it shall be comprised of not more than 15 percent zinc.
29.6 In accordance with 29.5, sheet and plate aluminum in contact with water shall be of an alloy of the 5000 series as given in the American National Standard Specification for Aluminum-Alloy Sheet and Plate, ANSI/ASTM B209; and cast aluminum shall be one of the alloys shown in Table 29.1.
29.7 Replaceable heater elements shall be replaceable without disturbing the grounding or bonding of the appliance or current collectors. See 53.50.

New section added;

Escape Current Test

35.2 The appliance shall be connected to a closed loop water supply system that is insulated from ground, accommodates insertion of an escape current probe and is provided with a variable flow rate pump. The maximum length of the water path from the inlet and outlet fittings of the product to the point of escape current measurement shall not exceed 12 in (300 mm). The water shall be the hard water solution of 36.5.1.
35.3 The appliance shall be supplied at rated voltage from an isolating transformer with controls set to the most unfavorable condition. An escape current probe (see 35.4) shall be connected to a milliammeter having a maximum 500 W input impedance and that is, in turn, connected to the equipment grounding terminal of the appliance.
35.4 The escape current probe shall consist of uncoated wire mesh screen having approximately 5 strands/in of 0.2 in (5 strands/cm 0.6 mm) diameter wire and measuring approximately 4 by 4 in (100 by 100 mm) and provided with a solid copper conductor for connection to the milliammeter. The conductor shall be no smaller than the equipment grounding conductor required for installation of the appliance. The probe shall be immersed to intercept the water flow from each outlet individually as well as the combined flow. The probe shall be located within 1 in (25 mm) of the water outlet openings.

New clause added;

An instantaneous water heater with a bare-element water heater of 2.3 shall be marked where visible during installation with the following or equivalent:


b) “For use on an individual branch circuit only.”


New clause added;

Equipment employing a leakage current collector of 29.1 shall also include the following safety instruction: “Supply this appliance only from a grounded system. A green terminal (or a wire connector marked “G”, “GR”, “GROUND”, OR “GROUNDING”) is provided for wiring the appliance. To reduce the risk of electric shock, connect this terminal or connector to the grounding terminal of the electric service or supply panel with a continuous copper wire in accordance with the electrical installation code”.

78 (previously 72)Info


The reference to measurements made from X-ray photographs have been removed from the 14th edition of UL 499.


New section added;


This new section includes new construction requirements, performance test requirements, markings and instructions for electric soap kettles (see standard for section details).


New section added;


This new section includes new construction requirements, performance test requirements, markings, and instructions for vivarium heaters employing thin film resistance heating elements (see standard for section details).


New section added;

Heat Guns Operating from Rechargeable Battery Power

This new section includes new construction requirements, performance test requirements, markings, and instructions for heat guns operating from rechargeable battery power (see standard for section details).

CUSTOMERS PLEASE NOTE: This Table and column "Verdict" can be used in determining how your current or future production is or will be in compliance with new/revised requirements.