Wikipedia
Emcor
EMCOR Group is a Fortune 500 company based in Norwalk, Connecticut. EMCOR provides mechanical and electrical construction, industrial and energy infrastructure, and facilities services to a broad range of commercial, industrial, utility and institutional customers.
EMCOR comprises 75 or more operating companies, has approximately 170 locations, and employs more than 33,000 people. The company was listed as number 421 on the 2015 Fortune 500 list.