Can a wire gauge be too large?

I'm an electrician...using larger wire will not hurt anything or cause any overload. The larger wire will cost more, the pathway or where it has to fit, and the physical size of the connecting means (ie. the size of terminal or clamp it has to fit in), will all be determining factors in just how big is too big. A larger guage wire will carry more current for any given distance than a smaller guage wire will. You should ALWAYS size the wire to the load it will carry. If not sure what size that is...find out, don't just guess. That's how an overload, overheating, and possible fire will happen.