It is used to conduct the flammability test of the material as discussed in IS/IEC 60947-1:2004 Annexure M.
The HWI test indicates a materials resistance to ignition when exposed to abnormally high temperatures resulting from a component failure such as a conductor carrying far more than its rated current.
HWI performance is expressed as the mean number of seconds required to ignite a specimen when wrapped with an energized non-chrome resistive wire that dissipates a specified level of energy.
