Pulling unidentified plugs out of sockets in an attempt to find one to charge your mobile is something we advise strongly against. Especially in an office environment. One plug might be the office printer. The other, your Boss's computer. To avoid this potentially explosive situation, charge your mobile with the USB Phone Charger instead. It is light and compact and has an auto-retract design so it doesn't get tangled up like a regular charger and is easy to carry.