I do handyman work in a large midwestern city.
I encounter a lot of older wiring that has been added to piecemeal,
over the years. Yesterday, I was working in a house that had been
built in 1911, or earlier, and originally had gas lighting. The wiring
was added later, in some cases with the J boxes attached directly to
the old gas piping.
I would welcome any information on the general ages of the wiring,
based on the type of materials used.
I would characterize some general types that I find, in this area, as
1) Indiviual wires strung on ceramic insulators, no conduit.
2) Fabric insulated wire (type V?) in black iron (steel?) pipe. These
conduits are generally 1/2" rigid pipe with the bends field bent into
the pipe, generally no fittings besides couplings and nuts at the
j-boxes. The nuts on the pipe threads are hex shaped.
3) Steel Armoured Cable (BX?) with fabric sleeving over fabric
insulated wire. Fittings are clunky, heavy castings. The nuts on the
pipe threads are hex shaped.
4) Steel Armoured Cable with paper sleeving over fabric insulated
wire. Fittings are somewhat lighter castings. Nuts on the pipe
threads are stamped steel squares with 4 notches in the corners.
5) Steel armoured cable with paper sleeving over plastic insulated
wire. Nuts on the pipe fittings are cup shaped steel with "star"
and what I would consider "modern" materials:
Steel and Aluminum AC with cast zinc fittings, and
EMT with cast zinc fittings.
Nonmetallic cable is not allowed in this area. BX is only allowed for
pull-in remodeling type use.
I'm not looking for a discussion of code here, but I would find it very
interesting to know what the approximate ages are of the various types
of materials that I find.
Thanks for any info you can provide.