Nothing at all wrong with oversized wires as long as the breaker lugs are rated for them. Not allowed to snip strands off to make them fit as in your photo. But...that shouldn't be the problem.

I'd suspect a bad breaker first (who makes "General Switch"?). Did it still hum after resetting? But, there also could be something loose or intermittent at the dryer (or the receptacle).

It sounds like the homeowner does this regularly? Anyway...there definately is a problem. It's beyond your "scope" to fully diagnose it. Report what happened and recommend investigation by a licensed electrician and repair by him or the Maytag guy depending on the source of the problem.

BTW...that's one ugly wiring job at the panel. I think it's safe to say that the cable exiting the side of the panel and disappearing behind the door casing is not an acceptable wiring method!

__________________
Richard Moore
Rest Assured Inspection Services - www.rainspect.com
Seattle, Washington