We use our cell phones, tablets and other devices so often that they feel like an extension of our hands. There are a few places where using a device that is plugged into an outlet can be hazardous, however.
Do not use a cell phone or other device when it is plugged into an outlet when you:
Are in or near a pool or hot tub. Water and electricity are a deadly combination. Electrical current running through water can cause shock or electrocution.
Are in the tub or by the sink. Never extend your cell phone or device so that you can reach it while bathing; also, do not plug it in near standing or running water.
Are in bed or other soft places. A device can overheat when placed on or under a pillow or soft bedding. Also, charging cubes and cords can malfunction, causing burns, shock or other serious injuries.
Hear thunder or lightning. Lightning can cause power surges that are not only harmful to electrical (charging) devices but also to you.
Source: Safe Electricity