Should I power my Pi and USB hub through the same power supply or separate ones? Because they both run. But which is better for the Pi?

2 Answers 2


That depends on what devices you want to use. Your power supply can only deliver a limited amount of current, which has to suffice to run your Raspberry Pi, your USB hub and all power consuming devices connected to both of them.

  • I have a keyboard and mouse plugged in
    – QwertyFish
    Commented Aug 30, 2014 at 18:40
  • That shouldn't be a problem.
    – tmartin
    Commented Aug 30, 2014 at 18:42
  • Cool thanks I was worried it would break the pi or something
    – QwertyFish
    Commented Aug 30, 2014 at 18:43
  • Connecting high power consuming USB hard drives or trying to charge your cell phone directly via the pi e.g. can break it. That's why you should use an active USB hub for such tasks. Nevertheless, if you overdo it, you can break your power supply and thus kill your Pi.
    – tmartin
    Commented Aug 30, 2014 at 18:59
  • It won't break it. A/B models will brown-out, which may not do good things to the SD card content; newer models simply won't power things that require too much current.
    – goldilocks
    Commented Jan 20, 2016 at 9:09

As long as the power rating of your power supply (that being the current it can provide) is high enough to power both the RPi as well as all the devices attached to the active hub (including the power needed by the hub) it is perfectly safe to operate all from one power supply. If on the other hand the necessary current is not provided by supply you may encounter problem. While breaking the hardware of the RPi that way is unlikely still a decreasing voltage of the power supply could cause a brown out of the RPi resulting in erratic behaviour and faulty I/O access, e.g. faulty write access to the SD card leading to bad blocks.

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