You might know the feeling. You plug in an electrical cord and the receptacle moves just a bit more than seems good and proper. How scared should you be?. A receptacle that is spongy or that slips around when you try to connect a plug to it is unnerving, and for good reason. Loose receptacles and electrical boxes can be dangerous and while they can be caused by age, faulty wiring of an outlet, or rough handling, the most common cause is probably insufficiently tightening the receptacle or electrical box fasteners... sometimes on purpose. The trouble is that movement in an electrical box can result in electrical connections that also work themselves loose over time, and that looseness can result in arcing, overheating, and fire.