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.

Is it OK to oversize wire?

Using larger gauge AWG wire offers you more flexibility in how your electrical system is laid out. Your electrician can add more outlets when your wiring has increased current potential. Larger wiring can sometimes be installed in risky areas where small wiring is not recommended.

Is using thicker wire bad?

Thicker wires provide less resistance, which entails that more electricity can pass through them. There is no significant benefit to using thicker wires compared to using thinner wires. With that said, there are still so many questions that homeowners ask when choosing which wires they should buy for their house.