Well that's a new one!
All electrical equipment generates radio waves, which can interfere with other services. My guess is that your mains charger is causing interference to your wifi signal. The solution might be to change the frequency which your router is using. Make and model, please?
Last minute thought: Since you refer to a 'hub', rather than a router, you might be using a BT HomeHub. If so forget about providing the make amd model and go directly to here:
http://bt.custhelp.com/app/answers/detail/a_id/14094/~/how-do-i-change-the-wireless-channel-on-my-bt-hub%3F
(Try the 'refresh channels' bit ahead of manually choosing a different channel).