Från Wikipedia:
"Unlike previous standards, the USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification: for copper cabling with AWG 26 wires, the maximum practical length is 1.3 meters (4.3 ft).[10]"
https://en.wikipedia.org/wiki/USB_3.0
EDIT:
Flera bud, även detta från Wikipedia:
(Under rubriken Cabling)
"The USB 3.0 standard does not directly specify a maximum cable length, requiring only that all cables meet an electrical specification: for copper cabling with AWG 26 wires the maximum practical length is 3 meters (9.8 ft).[89]"
https://en.wikipedia.org/wiki/USB#USB_3.0