I’m pushing through the brilliant book “Industrial Power System Grounding Design Handbook” by Dunki-Jacobs and Co. In it, the authors indicate that copper is endothermic (absorbs energy when converting from solid to liquid) and aluminum is exothermic (releases energy when converting from solid to liquid).

They claim that due to these differences equipment with internal aluminum construction has a much greater potential for destructive energy release during an arc fault vs. copper construction. Does anyone account for this difference in their analysis of systems? The program I use for arc flash evaluation does not give me an option for copper vs. aluminum windings in the distribution transformers so I can’t compare & contrast material types for IE levels. For panelboards I do have the ability to adjust for material type but it doesn’t appear to make a difference for IE levels based on a quick sample study I just did.

Thoughts? Is material type a consideration that needs to be addressed? I believe the answer is no but wanted the groups opinion.