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I have a transcend 1 TB external drive (usb 2); It has two usb cables but also works if i connect the thicker one. Do i need to connect both for it to work properly or prevent damage or something?

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I think it all depends on the device. Some devices need additional power to operate, they're able to get that extra power by using multiple USB connections. You can refer to this wikipedia article for specifics on USB 1.0 vs. 2.0 & 3.0. – slm Dec 27 '12 at 18:23
up vote 4 down vote accepted

It's safer using both, since Harddisk may consume more Power on spin up, as USB is designed for.

Fourthly, many consumers and computer users buy 2.5” hard disk drives as portable storage devices inside USB chassis. A lot of chassis like that have no additional power supply, while a single USB connector can provide maximum 500mA current. So, some hard drives requiring a lot of power may face serious stability problems or may not be recognized by the system at all.

More information provided here


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Thank you for your answer. – Sam Dec 27 '12 at 17:59

From the wikipedia article.

Some devices, such as high-speed external disk drives, require more than 500 mA of current and therefore may have power issues if powered from just one USB 2.0 port: erratic function, failure to function, or overloading/damaging the port. Such devices may come with an external power source or a Y-shaped cable that has two USB connectors (one for power+data, the other for power only) to be plugged into a computer. With such a cable, a device can draw power from two USB ports simultaneously.

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Thank you for your answer too. – Sam Dec 27 '12 at 18:00

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