I've read that one of the dangers of Y USB cords (if the two Y ends are attached to different devices) is that electricity could go the wrong way, frying a device.

So, in my case, I have the following issue. My Raspberry Pi doesn't have enough power to run itself and power an external hard drive, so what I was thinking of doing, is connect the Red and Black wires exclusively to the charger end, and the white and green wires exclusively to the Raspberry end.

Would this be safe? Do the Data wires and Power wires cross anywhere?

  • \$\begingroup\$ I believe that would work just fine. The danger associated with the Y cables is if one of the two "receiving ends" of the wire you attach a power source with a power source already being attached at the the single-end side of the Y-cable. \$\endgroup\$ Jul 4, 2019 at 23:30
  • \$\begingroup\$ which external hard drive are you using? ... perhaps you need a powered USB hub \$\endgroup\$
    – jsotola
    Jul 5, 2019 at 0:57
  • \$\begingroup\$ @jsotola It's a seagate expansion 1TB external HD. According to lshw, it's "configuration: driver=uas maxpower=500mA speed=480Mbit/s" \$\endgroup\$ Jul 5, 2019 at 17:53

1 Answer 1


I would keep the black wires connected to keep a common ground reference in the system. Otherwise it should work, seen similar cables in use.


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