The southbound carriageway between junctions 17 (Sandbach) and 16 (Stoke-on-Trent) reopened at 6.15am after a three-hour closure.
The northbound carriageway reopened an hour later at 7.15am.
There is just over 6 miles of congestion on the southbound approach, and 5 miles northbound.
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Highways crews are beginning the process of re-opening the northbound carriageway, where tailbacks are already building.
The road closures are expected to impact on traffic throughout the M6 motorway network.
It is understood that the overhead power cable had been damaged after a collision last night around 7.40pm.
The power supply company attended and traffic was diverted (Northbound) via the A500 westbound, A5020 north and A534 north to rejoin at junction 17.
Southbound diversions were also in place in reverse order.