Homes built prior to 1950 often feature old-style electrical wiring that is about as technologically advanced as the football helmets from those days. Knob-and-tube wiring (so called for the ceramic knobs and tubes that protect the wires at turns and pass-throughs) are now considered dangerous. It worked well when it was new, but degradation and the availability of modern alternatives make knob-and-tube wiring obsolete.
Upgrade from knob-and-tube wiring and you will reduce the risk of shock and injury while providing better and more reliable power to your larger appliances. Just as critically, you will probably need to replace knob-and-tube wiring in order to obtain new homeowners insurance and get a mortgage.
Why You Should Upgrade Knob & Tube Wiring
Electricians and insurance companies alike recommend upgrading from knob-and-tube wiring in order to protect your home and personal safety. It is also listed as a requirement by the InterNachi inspectors. Here’s why knob-and-tube wiring has become outdated:
- No grounding wire: knob-and-tube systems have only hot and neutral wires. This creates a shock and fire hazard, and the outlets are all two-prong.
- Old and brittle: age and overheating from modern energy demands make the wiring and infrastructure liable to degrade rapidly now and in the future.
- Insufficient power: knob-and-tube homes were designed for 60-amp service while modern homes typically use 200-amp (or at least more than 100). Large loads blow the old fuses and increase fire risks.
- Problematic repairs: since 1950, the home’s wiring, insulation, and other infrastructure have likely been worked on by handymen without real knowledge of knob-and-tube safety. Amateurish or misguided repairs like covering knob-and-tube wiring with insulation increase the risks.
Do I Have to Rewire the Whole House?
Upgrades to knob-and-tube wiring do not necessarily mean ripping out all old wiring and replacing the whole system. In some cases complete replacement is the best long-term solution. The job does not have to be that complicated, however.
Old wiring can often be left in place but deactivated. We can also make the most needed upgrades — replacing connections, adding a grounded wire, switching from fuses to circuit breakers — while leaving some safe wiring in place.
Rewiring a Home with Knob & Tube Wiring
Every knob-and-tube rewiring project goes a little differently. Consult with a licensed electrician in order to determine your best course of action. Some primary considerations include:
- First, a professional electrician should locate all knob-and-tube wiring. Old wiring left active will remain a safety hazard.
- Cutting into walls and other small disturbances will probably be necessary. Make sure you work with an electrician who understands the importance of respecting an antique home.
- Map out the wiring if possible and make notes about major appliances and heavy-usage areas of the home.
- Check with your insurance company about whether they are okay with inactive knob-and-tube wiring being left in place. If you are not removing the old wiring, it can be covered up without safety concerns, after it has been fully decommissioned.
- Full rewiring makes a ton of sense — the actual wires of the knob-and-tube set up are probably original (from 1950 or earlier). Some circuit wiring may be used, however, with grounding wire and proper connections added.
Are you living with knob-and-tube wiring or considering buying an old home that needs electrical upgrades? Contact us for a consultation and estimate — we’ll help you get up to speed with ample, reliable power from a modern wiring system.
