Re: Knob & Tube Splices
Hi, it's me, the home inspector again.
Jeff, if I saw the wiring in your picture in a house I was inspecting, I wouldn't be suggesting splice repairs and boxes. I'd recommend rewiring that circuit and any others that look like it.
Not only are the porcelain tubes missing, the wires are run too close together and there are missing knobs as well. But the real problem is that the hands that did this work almost certainly created problems elsewhere in the circuit, perhaps in places that are presently concealed.
I'd stick to my guns on this one. And no realtor, home seller, or even EC would be able to talk me out of that recommendation.
On a side note, I was taught that a properly made up wire nut splice is superior to a soldered western union splice (or telegraph splice) for two reasons. First, the wire nut exerts pressure on the splice, which is more important to a low resistance connection than surface area, particularly since the lead and tin in solder are relatively poor conductors. Second, the copper conductors in old K&T wires were coated with tin to protect the copper from reacting with the old-style rubber insulation. With a western union splice, there's practically no copper-to-copper contact. Whereas with a wire nut, the spring on the nut cuts through the tin to make some contact with the copper.
If you have to make repairs to an existing K&T system, wire nut connections are superior method.
- Jim K
