Is the Beaglebone black USB port protected against backflow current?

I need to hook up a HDD to my Beaglebone Black running Ubuntu. I already configured it to mount everything automatically and it already worked with a USB drive.
I found this cheap USB cable with a Y form that would provide the power the HDD. There’s a main USB cable with all the 4 connections and a smaller cable that is connected to the + cable and the ground.
I’m going to power the HDD by plunging the smaller cable into an USB current adapter guaranteed 1A output and the one with the data connection to the Beaglebone.
Before any testing i found that there is NOT any kind of diode between the two cables, so I’m worried if it’s still safe to set it up I has intended.

Anyone can help me? Thank you in advance!

The problem with what you are trying to to do id not current. It is the fact that the 5V rails do not come from the same source. In a PC the 5V is the same for both ports.

You would be better off powering the HDD from an external source totally and not using the 5V rail on the BBB USB connector to provide the power.

Can you send a picture or model number of this cheap cable yo are referring to ? It does not sound like a cable to me, but a USB HUB. But I would need to see if first.

Gerald

I think his cable is just stealing another 500mA from another USB port, because older disks tended to exceed the 0.5A power draw on startup.