I am familiar with microwaves and the quality control standards the appliance manufacturers must go through to bring a product to market. In most cases, a product has to go through extensive testing, simulating a series of conditions, before it can be sold. Given the facts in this case, it is troubling that the microwave started spontaneously. This is extremely dangerous, as it can cause a number of hazards including leaked radiation and fires. This issue has been reported in some models, and it is usually symptomatic of a defect. By reviewing the specifics of this case, the exact model and different circumstances, I can describe the elements of the defect.