As a Diamond Certified company rated Highest in Quality and Helpful Expertise, REFCorp specializes in the older wiring found in many San Francisco homes. Our technicians are familiar with the unique troubleshooting requirements of knob and tube wiring. We are happy to do a simple repair to your existing system or a complete replacement, whether you're a homeowner, a property manager or a business! A list of our other specialty areas of expertise, reviews (verbatim customer responses), video profile, Expert tips and video, and independent rating details are all available on our online Diamond Certified report.