I have this hub, with the Pi Zero:
I know that I need to power the Pi via the USB power port and that the Hub is powered a separate power supply; provided when you purchase it.
But I'd rather not use lots of wall sockets - I already need 10 for my current computer, so I'd like to use 2 or less (including the screen).
To achieve this, I would need to power the Pi from one of the USB Hub's ports. However, I don't want to damage the Pi of course - so is this safe to do?
Yes, you can power the Pi from the hub with an extra usb to micro usb cable coming from the hub to the PWR input on the Zero. This shouldn't cause any problems whatsoever, no feedback.
You really don't need that extra cable going to the PWR input anyways. With most powered hubs you should be able to just plug the hub's power in and plug the data cable of the hub into the Zero. Without plugging anything into the PWR port, it should boot up.
Video of this here, at about 0:45 he turns it on.
This is back powering, and it is pretty safe on the Raspberry Pi, as long as your USB hub doesn't surge over 5.25V, which I've never seen a hub do. So I'd say this is very safe, but I'm sure someone's got a story about breaking their Pi like this, as there is no polyfuse for the current to go through when back powering.
An externally powered hub should be more than capable of powering both your Pi Zero and whatever peripherals you want to connect with it. The RPi itself only requires ~200 mA of power with a full load. That number will be significantly less under lighter situations.
