Below is a picture of knob and tube wiring which has been a safety concern because of its tendancy to overheat when insulation is packed around it. Also since it have been around for some time now the chance of it having been overheated due to overfusing is much higher. This have become a issue with insurance companies as they no longer want to insure houses with more than one circuit of knob and tube. There may still be a couple insurance companies that will insure knob and tube wiring and if you know of which please let us know.

When can your expect to see knob and tube wiring in a house. It was installed in homes up to the 1950's and you will likely see it in homes built before there was wiring installed initially.

 

 

 

 

 

 

 

 

Knob and tube wiring was sometimes installed with a fuse on both the neutral and the power wires. This is a concern because in the event that the fuse on the neutral is blown the home owner will think that the circuit is no longer live when in reality you can still be hurt by injured because the circuit will still be live.

Because the uses of electricity has changed so much in the past 60 years since it was last installed it is common to find circuits that were extended by home owners who may or may not have done a good job. Because knob and tube was installed without junction boxes people think they can still make connections without junction boxes when in fact this is not any longer allowed. Lastly since the wiring is typically quite old the chances of it having been damaged is higher and it has aged, meaning the sheathing may be brittle or broken.