Zurich-based ABB Ltd., (NYSE: ABB), the world’s largest maker of power-distribution equipment, has agreed to buy US-based Thomas & Betts Corp. for $3.9bn to expand its North American distribution network and boost sales of low-voltage gear.

The U.S. is the world’s largest market for low-voltage gear, which is ABB’s most profitable line of equipment, and Chief Executive Officer Joe Hogan,  said the purchase will help his company build critical mass and distribute its products in the region.

“This fills one of the largest gaps in the company, which was not having a meaningful presence in the world’s largest low- voltage market,” Hogan said on a call with journalists.

Hogan already bolstered ABB in the U.S. with the January 2011 purchase of Baldor Electric Co. for $3.1bn.

The Swiss company estimates the purchase will double the size of the low-voltage market in North America that will be open to its products to approximately $24bn. Previously, its revenue in low-voltage in the region was just $240m.

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