Shaykh Saalih Al-Fawzaan was asked:
What is the ruling on using the electricity at work to charge a cellphone or the likes of that?
“There is no harm in something small and temporary. As for a lot and continuous use, then that is not allowed because it is exploitation due to [the electricity] being a public good, not personal and specific. It is not allowed to continuously do that. However, something temporary, like his cellphone needing to be charged at times, then there is no harm in that”
Faisal bin Abdul Qaadir bin Hassan