Getting A Phone Line Installed In A New Build . As necessary, trim damage from the old wires and strip the insulation from the tips. Use our broadband checker to see if fibre’s an option at your new build’s address. Medium Sized Office Network / Phone Closet Upgrade » Tranquility Computers from www.tranquilitycomputers.com Bt charges £130 to install a new one, for instance. Other providers can charge anything from £20 upwards, though their prices are likely to be on par with bt's. From what i can tell: