UPDATE 1-Williams expands Transco Northeast US gas line

(Adds details, recasts)

NEW YORK Nov 19 (Reuters) - Williams Cos. (WMB.N) said Thursday it placed into service an expansion of its Transco natural gas pipeline, increasing firm transportation capacity into the Northeast United States by 102,000 dekatherms per day.

The expansion increases the total system capacity on the 10,500-mile Transco system to approximately 8.6 billion cubic feet per day, the company said in a statement.

The Sentinel expansion project was completed in two phases, the second of which was placed into service this week. The first phase, which increased capacity by 40,000 dekatherms per day, was placed into service in December 2008.

Phase II construction included the addition or replacement of 14 miles of pipe and eight meter station modifications at various locations in Pennsylvania and New Jersey.

Phase I construction included the addition of approximately four miles of pipe in Pennsylvania, two meter station modifications and compressor station upgrades.

The Transco pipeline system transports natural gas to markets throughout the Northeast and Southeast U.S. (Reporting by Eileen Moustakis; Editing by Christian Wiessner)