This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The different methods of wiring which are now approved by the National Board of Fire Underwriters, may be classified under four general heads, as follows:
1. Wires Run Concealed in Conduits.
3. Concealed Knob and Tube Wiring.
Under this general head, will be included the following:
(c) Armored cable.