What classification of fire cause does NOT involve any deliberate action to ignite a fire?

The classification of fire cause that does not involve any deliberate action to ignite a fire is accidental. Accidental fires are typically the result of unforeseen events or failures, such as electrical malfunctions, equipment malfunctions, human errors, or other unintentional causes. This classification distinguishes itself from fires that are initiated by deliberate actions, such as incendiary fires, which are intentionally set.

Natural fires, while not deliberate, are caused by elements in nature, such as lightning strikes or wildfires caused by environmental conditions. The term "undetermined" refers to cases where the cause of the fire cannot be conclusively identified. Thus, accidental fires are characterized by the lack of intent behind the ignition, making this classification correct for the question.