Centrica, the parent company of British Gas, has bought Connaught Compliance's gas and electricity services business for £11.2m in cash.
Connaught Compliance was one of three Connaught divisions placed in administration earlier this month. It provides health and safety compliance advice across a range of sectors and employs 1,800 staff.
The acquisition will give British Gas Business over 20,000 customer contracts, mainly in the private sector, and a 600-strong work force, including approximately 400 gas and electricity engineers who specialise in the installation, service and maintenance of commercial gas boilers and electrical systems.
British Gas Business, the utility's business-to-business division, currently provides service and maintenance contracts to its 750,000 customers.
The deal includes Connaught's training academy in south Wales.
Kanat Emiroglu, managing director, of British Gas Business, said "This acquisition gives us the platform that is needed to develop and rapidly build a complete energy solutions business and accelerates our growth strategy in the business energy services market, which is expected to be worth £2bn by 20151.
“It is great news for the people at Connaught, its customers and for British Gas Business's existing customers."