One of the things that buyers often wonder about, assuming they have heard the term, is whether or not an older home they are buying might have knob and tube wiring. Any old house, up through the late 1950's approximately, might have some knob and tube wiring. And if they are really old they are pretty much bound to have had it at one point or another. The house I grew up in as a kid had knob and tube and that was an upgrade -- it had been gas lights. Knob and tube is outdated, and insulation might be brittle, and it does not have a modern equipment ground, that third wire. Some insurance companies will not insure knob and tube, others will. But they usually charge a premium for doing so. How dangerous knob and tube is, if at all, often depends on how much hacking has been done to it in the past by unknowing homeowners or tenants who were trying to rig up some wiring concoction. Here is a point: Often the inspector will not find obviously energized knob and tube wiring. That is, he or she might see past signs of it -- photo below. The wiring has been, in obvious areas, disconnected. Does that mean the inspector should state that there is no knob and tube? Absolutely not, unless he or she wishes to end up potentially in hot water. The fact is that, often, even when substantial amounts of knob and tube wiring has been removed, it is still on premises somewhere -- maybe leading out to a garage, or maybe behind the refrigerator which is not pulled out, or maybe it is gone from receptacles but it is still in place at ceiling fixtures. The cautious home inspector can report what is seen but if a client wants a "guarantee" that all knob and tube is gone then refer that to a licensed electrician. By the way, my experience is that most licensed electricians will not give such a guarantee either -- unless they are rewiring the house so they see, and know, every inch of wiring. Thanks for stopping by, Steven L. Smith
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Steven,
Good information. It is almost impossible to get insurance for this in my area.
Just curious if everything in the house is finished, how would the inspector know if there is any? If the attic in your photo was finished would you know it is there?
Jeana,
There are lots of ways to be pretty sure it exists -- old cloth wiring in the panel, taking a receptacle cover off and peaking, two prong receptacles, often with reversed polarity, views of it. You have a strong chance of seeing it in attic and, around here, crawl space areas. If there was no way to get in those areas, which seems weird because there is usually an attic, then it would be hard to tell unless you saw it outside, in the garage or saw the clues I described earlier. Age, of course, is a factor. It is is from 1930, you know it was there once. If it is from 1976, then not something to consider. This field is all about processing clues.
If it is in one place, it may be in another! There might still be a short leg somewhere. Good advice on the post Steve!
I did have one listing that this wiring had been in. Not too sure now if it was still in use. Hope not.
If you can see it in the attic or basement, you can bet your life that it is in the walls.