The Southbound carriageway of the A22 at Hailsham is closed due to downed power cables.
Traffic has been disrupted since about 1pm this afternoon, The northbound carriageway has been re-opened and engineers from UK Power Networks have been called.
The southbound road will remain closed until the cables have been removed and engineers have declared the scene safe.
A spokesman for UK Power Networks said: "UK Power Networks engineers are working as quickly and as safely as possible to restore power supplies to 294 customers in the Polegate Road area of Hailsham following a road accident at about 12.40pm today (April 18).
"We were notified by the police that a lorry had brought down some overhead electricity lines.
Engineers are already on site, making the area safe and beginning repair work."