A record-breaking cargo of oilsands equipment en route from Idaho to Alberta has been stopped after knocking out power to about 1,300 customers. (Jeff McIntosh/Canadian Press)

A record-breaking load of oilsands equipment being transported to Alberta from Idaho by road has been stalled after little more than 100 kilometres.

Imperial Oil is moving a test load about three storeys tall and eight metres wide from the port of Lewiston, Idaho.

It's the heaviest load ever moved by road in the state.

As it left Lewiston, it snapped a large tree branch and delayed traffic for longer than it was supposed to.

Imperial spokesman Pius Rolheiser said it had a bigger mishap down the highway.

"It came in contact with a guy wire that supports an electrical pole," said Rolheiser. "When we became aware of that situation … for safety reasons we halted the move and ultimately made the decision to park the module."

Power was knocked out to about 1,300 customers for a few hours.

Rolheiser said the load moved 101 kilometres in about six hours, and is now parked in a roadside turnout.

It will remain there until the trucking contractor files a report with the state's transportation department.

While Idaho is a landlocked state, it does maintain one port at Lewiston thanks to the Columbia-Snake river system.