Look on the can of material for the recomended time. It varies between water based and solvent, and even within a single manufacturer's various types.
For a heavy point load like a TV you might want to wait a week to ensure the material has fully cured.

Well, I called myself reading the can for that info, but maybe I just missed it. Thanks for your advice and your reply!

The manufacturer should be able to give you an exact answer. Remember curing times are based on specific heat and humidy that most homes don't have.

I'd wait at least a week, probably closer to two.

Mike

Polyurethane takes about a year to cure completely. But that doesn't mean that you have to wait a year to use it. You could put a wood or cork pad under the tv set. I have some 8 inch diameter cork on masonite pads, under flower pots. They work great.

A week or two for waterborne polyurethane is just about all the time you will need to wait. Still...protecting the finished surface to keep it looking good is a good thing.

In my experience, the water based product is not as 'hard' as the resin based. Should the finish get a little 'dull' try some polishing compound (not rubbing compound) from a auto paint supply store. I have re-polished my round oak table a couple of times and it looks really great.