Are you a new home owner or looking to become a home owner? Knob and tube is something I have seen come up time and time again as an electrician. I have inspected housing in just about every town from Centralia to Tacoma. Beautiful custom homes on the hills facing the Tacoma Narrows bridge to tiny Craftsmans in the heart of Olympia.
Those homes in my opinion have the most character, the most stories, the most history. Generations of families grew up in these houses and a lot of love was put into the home when it was built. Knob and tube is the most modern technology they had. They didn’t know the importance of having a grounding conductor. There was no such thing as plastic. Electricians had never even heard of a wire nut and the standard practice to fix a joint was to twist the wire together, then solder it, and if it held well they would wrap it with cloth that glue was applied to one side.
So what is knob and tube you may have asked yourself? In those days the wire was wrapped in cloth and it would rest on ceramic knobs that held the conductor as it ran through the house. The tubes were the insulators places in the bored holes of the house where the wire could pass through. In a perfect world, knob and tube is a relatively sound way to wire a house. The line voltage (the hot) was spaced a good 8 inches or so from the grounded conductor (neutral). So when it is run through the walls it is very hard for those two to ever come in contact and create a short circuit fault.
But as you can imagine over the course of 100 years, that cloth may have totally broken down or be so brittle that very little touching of it may make the remaining sheathing fall off. Then imagine a network of metal wires running through your house like I-5 with overpasses and tunnels. Some spots having a large remodel going on to accommodate the new traffic with bare conductors the sheathing has completely become exposed. Imagine the thoughts running through a worker who wants to insulate an attic and he came across a beautiful display of knobs running parallel to power all the odds and ends in the house. The fear of laying across the line voltage and the neutral and becoming part of your electrical system as his body becomes the conductor for electricity.
It is rarely an easy task to replace all of the knob and tube in the house. In fact it is not required to replace it, there are code sections in the NEC that outline what can be done if you splice into it. What can be done to remedy this wiring method? My suggestion would be to have a Professional Electrician such as myself (Manny) inspect the integrity of your wiring. From an inspection we could come up a plan of attack to either replace all of it or leave the wire that is not easily exposed and behind a wall of lathe and plaster or thick car decking.
New code relies on the safety of a grounding conductor to make a fault current path so that if the line voltage or neutral come in contact with an unintended path it will such off to make that circuit safe. The safest technology to date relies on arc-fault safety breakers that will shut off as soon as it sees an imbalance in what the breaker is outputting.
Its a daunting task but I have rewired many homes in University place, Tacoma, Olympia, Tumwater, and Tenino. The list grows the older I get. I can do the replacement with minimal sheet rock and lathe and plaster repair. If you want to save money and I have full reign to make holes and paths where I please, I can get the job done much faster.
Here at Empowered, we would love to tackle your knob and tube replacement. Or at least give you the peace of mind of where it is located and it’s integrity.