If you put too many wands in the same place (inventory, bag, stash, floor pile, etc), there should be a risk that the magic in them will reach a critical mass that sets them off and blows some of them up. This would destroy only wands, not any other type of objects stored with them.

The intent is to address a balance issue with wands where the player steadily accumulates them over the game and has a huge arsenal of them, many of which aren’t even that useful, by the late game.