I'm not sure that's the right way around. With gas leaking out, you end up with a large volume of combustible vapor mixed with air (gas cloud), and when that's ignited, usually through turning on a light-switch, the resulting shock wave is powerful as hell - taking off doors, ceilings, etc. Often you get secondary fires breaking out (especially if it was from petrol fumes), but not always.
Gas was a popular way for thieves to blow apart bank machines because you just fill the space with it, ignite it remotely (unless you have a death wish), and then the force blows apart the safe and they run off with the cash.
With an electric charging point, you'd assume a lot more fire damage as it would likely have burned to deflagration - meaning, a fire broke out first and then the resulting gases from it built up so much in a confined area that an explosion occurred.
Investigators would be able to determine quite quickly if it was a bombing - the evidence would be obvious (crater size, types of materials, presence of certain residues, etc.).
TLDR: fuck knows, but I doubt there's anything suspicious going on. Impossible to really tell until more info is released, though.
