Thanks for the answers last week on knob and tube now I have more. This K&T system I am replacing seems to form a loop, that is it encircles the entire attic then attaches back to itself. Was this standard practice in 1903? It's not too easy to see it all since someone buried it in 2 feet of rock wool! I've been doing a lot of digging.
Also I was curious if anyone knows when houses were first wired with bladed receptacles. It appears this house originally just had Edison sockets in the ceilings- you can see where receptacles were added later by splicing BX onto the K&T with those funny looking things the older guys call "monkey faces".
Sorry for all the questions- I haven't had the opportunity to do any residential K&T replacements before and I am facinated by it.

Some K&T's longevity speaks for itself.

Once in a while one may stumble on an old grange hall, or other structure that time forgot to view a pristine install unhithered by time & intervention.

The problem(s) started with the add-ons, the insulation, etc etc...

Brian, just beware of the K&T 3-ways which switch the noodle....

Brian,

Be aware that Article 394.12 prohibits insulation around Knob and Tube wiring. Insulation interferes with the ability of the conductors to dissipate heat.

Brian:

Not sure about the loop question.

As to the wool, that stuff can irritate your skin; you may want to be sure to have gloves, a mask and goggles to protect yourself. (What's the difference between vermiculite and rock wool? I believe that vermiculite has asbestos in it?)

This thread has some photos of old parts...

Check the library for these books which probably answer your questions (I know that the first one has a lot of history in it):

Old Electrical Wiring Maintenance and Retrofit by David E. Shapiro (out of print)

Your Old Wiring by David E. Shapiro


[This message has been edited by ThinkGood (edited 02-21-2003).]

Redsy,
Yes I was aware that you do not ever pile insulation around K&T. But the home inspector didn't mention a word about it to the new buyer, in fact he told her that there was K&T and that it appeared to be in good condition! Most of the untouched parts were in good condition but then there were the flying splices (one without even tape where someone spliced in an outdoor motion light.)
I am re reading Shapiros book but I have not seen mention of a loop. The switching arrangements are kind of scary though, especially today as we are used to safer systems and a lot of respect for electricity has been lost by the average untrained person.