Only use this login to access MyHome, MyAgreements or ULiQ. Each option requires a different username and password.

North America
Europe
Denmark
France
Germany
Italy
Netherlands
Poland
Spain
Sweden
Switzerland
U.K.
Latin America
Asia Pacific
Argentina
Brazil
Mexico
Australia
China
Hong Kong
India
Japan
Korea
New Zealand
Singapore
Taiwan
Broader and deeper than ever, UL's third annual global study examines manufacturer and consumer concerns and priorities across a wide range of product-related considerations.

more >
UL is proud to share New Science, a powerful initiative showcasing important ways we are making our world safer through fundamental discovery, testing methodologies, software and standards across five areas.
more >

STANDARDS

Thousands of products and their components are tested to our rigorous requirements every year.

DASHBOARD

UL's Dashboard tools enable businesses to meet evolving marketplace needs by being smarter, more efficient and faster than ever before.

learn more >

LIBRARY

MARKS HUB

SERVICES

STANDARDS

Share

UL 746C FAQ

The following FAQ has been prepared to assist you in understanding the revised requirements in UL 746C which became effective June 1, 2004.

  • How will I be notified if my product is affected?

    A letter was sent notifying manufacturers of products that have been affected. The letter summarized the changes in UL 746C and outlined the information needed in order to proceed with the review process.

  • What products are affected?

    The Standards and categories directly impacted include all portable unattended household equipment and portable commercial attended and unattended equipment.

  • What are the major changes to UL 746C?

    For the products affected, the flammability level for the enclosure is now required to be a "V" (V0, V1, or V2) rated material.

  • Are there any exceptions or options?

    There are some exceptions and options to choose from.

    1. An HB-enclosure material may be employed if it complies with the end-product flammability test in accordance with sections 17 or 18 of UL 746C.
    2. If a metal or V-0 sub-enclosure houses all insulated or non-insulated live parts that involve a risk of fire, then the overall polymeric outer enclosure may be classified HB. See paragraph 4.3 of UL 746C.
    3. An HB-enclosure material may be employed in portable unattended household equipment provided that the equipment complies with the requirements in section 4A of UL 746C.
  • How are component manufacturers affected?

    Some end-product manufacturers may choose to employ an HB enclosure material and will require a review of the materials supporting and within 3mm of each connection. Component manufacturers may need to comply with the requirements as outlined in section 5. Section 5 (portable unattended household equipment -- alternate path) of UL 746C outlines requirements for electrical connections. The "alternate path" requires that all electrical connections such as wire nuts, splicing wire connectors, quick-connect terminals, terminal connectors, multi-pin, and other forms of wire connectors shall comply with their respective component standards and employ materials rated V-0 or V-1. This means that the component manufacturer shall mark the flammability classification of the insulating material on the connector, smallest unit container, or on an information sheet placed in the smallest unit container. Other small-scale flammability classifications in accordance with paragraph 5.3.1 are also acceptable. A minimum glow-wire ignitability temperature (GWIT) and a glow-wire flammability temperature (GWFT) of 750 degrees C for the material are also acceptable.

  • How are plastic manufacturers affected?

    Plastic manufacturers may need to work closely with both end-product manufacturers and component manufactures to choose the appropriate plastic material for their particular application. Since glow wire indices may be offered as an alternative design choice parameter for component manufactures, glow wire data on the plastics recognition card may be helpful in selecting the appropriate material.