July 1 (Reuters) - Enbridge Inc's (ENB.TO) Texas Eastern Transmission (TETCO) unit said it expects to have more clarity on when it can return a U.S. pipeline to full operating pressure soon after submitting an engineering report to federal safety regulators by mid July.

TETCO declared a force majeure on May 28 after the U.S. Pipeline and Hazardous Material Safety Administration (PHMSA) required the company to reinstate a 20% pressure restriction on two of three lines (Lines 10 and 15) that make up its 30-inch system between its Kosciusko, Mississippi, and Uniontown, Pennsylvania, compressor stations effective June 1.

That reduction cut flows from Appalachia to the Gulf Coast on the 30-inch system at the Owningsville compressor station in Kentucky to an average of 1.1 billion cubic feet per day (bcfd) in June from an average of 1.9 bcfd in May, according to Refinitiv data. The average was 1.3 bcfd over the past week.

In a notice to customers late Wednesday, TETCO said it "expects to be able to provide more definitive guidance on a potential return to service timeframe shortly" after submitting the engineering report to PHMSA.

Previously, TETCO said it anticipated the earliest the 30-inch system could return to full pressure was late in the third quarter of 2021.

PHMSA's order came as part of the agency's increased monitoring of TETCO after three explosions in the last few years.

The first was in January 2019 in Ohio, the second in August 2019 in Kentucky, which was fatal, and the third in May 2020 in Kentucky.

Before allowing TETCO to return to full pressure after the third explosion, PHMSA required TETCO to conduct inspections and submit a request every 90 days to remain at full pressure.

PHMSA ordered the reduction after TETCO found "an anomaly" during a recent inspection that the agency wants to investigate.

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