USB loading turning vWii off
So my Wii U is softmodded, and after having problems with a previous USB drive I decided to get a hard drive, now with the Wii U not having enough power to actually power an external hard drive I have to plug it into a hub and the plug for it is broke so I have a plug into the mains that has a usb cable that runs to the usb hub, thus powering the hard drive whilst the Wii U is turned on. Now when I actually come down to doing something involving the hard drive ie loading games, watching something on WiiMC the Wii U will just turn itself off abruptly. I'm getting a new plug either way because the one the seller sold me is faulty but I'm wondering if it has something to do with the way I'm powering the USB hub as the Wii U turning itself off just seems so odd. Any help?