From my knowledge about electricity I have found out that it is totally unsafe to use Cell phones/ electronic devices while they are plugged to power for charging. This is because: -

1. Cell phone chargers nowadays have only two plugs(Live and Neutral) connection to the power source instead of three plugs (Live, Neutral and Earth). The earth is meant to protect the cell phone device and any person in contact with it in cases of power surge. So what it means is if you are charging your phone with a charger that has no earth connection plug and a power surge occurs, current can flow through your device into your body to the earth using your body as the earth connection to complete the circuit. Only in rare cases will any person survive such a shock.

2. If short-circuit occurs your device becomes energized. Even if your device has a complete plastic insulation case it is not earthed against inductive current. Hence your body will create the earth connection required to send the induced current to earth if you are in contact with the device. The battery alone cannot produce such induction.

Do not use your device when pluged. Life has no duplicate.