The motorway between junctions 24 and 25 at Ainley Top, near Huddersfield, was shut from around 3pm to allow Northern Powergrid to carry out the works, according to Highways England.
It has since re-opened, but traffic disruption is occurring.
Those travelling to the John Smith's Stadium to see pop band Little Mix were urged to allow extra time.
Highways England said that although the road has been re-opened, queues remain in both directions but should start to clear.
The agency thanked drivers for their patience.