Engineer Insight

UL 1995 vs 1996 Simplified

by Jeff Elrod

UL1996 Standard (Duct Heaters)

  • Duct Heaters are judged under U.L. 1996 only.
  • Duct Heaters are tested for duct applications at least 4 feet from heating or cooling equipment.
    • An exception to this can be made if the heater is tested and approved by a regulatory
      agency for use with a specific piece of equipment and indicated as such on the product
      label. (See UL1996 Section 2.1.3 & 45.1.8)
    • Refer to Tutco installation instructions for pertinent requirements.
  • Duct Heaters are required to have secondary temperature protection.


UL1995 Standard (Packaged Heaters)

  • Can be similar to a Duct Heater, but is typically judged under (but not limited to) U.L.1995.
  • These heaters are tested in, on or within (but not limited to) 4 feet from heating and/or cooling
  • They are specific to the piece of equipment they were tested with.
  • In some cases these heaters do not require secondary temperature protection if line duty primary
    temperature protection is used or if the controlling contactors or relays are rated 250,000 electrical