Undersea internet cable manufacturing turns processed glass fibers into a protected, tested cable prepared for installation at sea. Business Insider’s report, published October 11, 2026, follows SubCom’s New Hampshire operation from the production floor to a cable-laying ship. The work continues beyond the factory: installation, system testing and underwater repairs are also part of the process.
How glass becomes a protected cable
Business Insider follows glass fibers as they are processed and built into cable. Steel wire protects the fibers, followed by a seam-welded copper layer. The cable’s outer protection varies with the conditions where it will be deployed.
Testing, repeaters and reported production figures
According to Business Insider, the factory began operating in 1953 under Simplex Wire and Cable Company. The report puts its annual cable-production capacity above 40,000 miles and says SubCom’s output doubled since 2018. It also describes cable pans in the testing room that weigh about 70 tons each.
Repeaters—signal-boosting equipment placed along the cable—are about 55 miles apart in the system discussed. Business Insider gives that cable a design life of at least 25 years.
From the factory floor to installation and repair
Business Insider follows cable as it is loaded onto a ship for deployment. The featured ship’s cable-storage tank rises eight stories, with workers stacking cable in loops. The report also follows installation and repair work involving remotely operated vehicles and fusion splicers.
SubCom describes a manufacturing campus in Newington, New Hampshire, and says its work covers installation through system testing, using its cable ships and tools, as well as wet-plant repairs. In subsea cable systems, the wet plant is the equipment installed underwater. SubCom describes its installation and maintenance services.
