Extension Cord Question

I've learned on these forums that you don't want to use too small an extension cord to plug into something that requires a heavy load, such as electric heater, your RV, etc. My question is can you use a heavy duty cord on items that do not require one? Specifically, we're putting up Christmas lights and I'm wondering if I can use the heavy duty cord I use to plug the RV into the house (via the adapter) to run low voltage lights? Will it cause damage? Thanks.