On Tue, 25 May 2021 23:28:17 -0600, bud-- wrote:

On 5/25/2021 4:56 PM, micky wrote:
A friend of mine bought a house in Baltimore County 5 or 10 years ago
that still had knob and tube wiring, at least in the attic. My friend
says you can't get a mortgage if you don't pass inspectinon and you
can't pass inspection with k&t wiring.

What do you think happened?


I think it is modern redlining - an excuse to not mortgage (or insure)
old houses.

Example:
http://web.archive.org/web/20040825060154/http://www.maine.gov/pfr/ins/hearing_2003-13680.htm
An insurance company was sued by a homeowner. Insurance was not renewed
because the home had some K&T. The homeowner provided evidence the
installation was in good condition. "The company provided no
justification for its position that knob and tube wiring per se
automatically provides grounds for nonrenewal." The court ruled against
the insurance company.

Years back the NEC prohibited insulation in contact with K&T. I don't
think there was ever any evidence that had caused problems. The head
electrical inspector for Minneapolis, where a lot of insulation has been
added, provided a comment that he saw no "record of hazard". After the
provision was enacted California was sued and could provide no record
of a problem. California and a few other states now allow insulation.

K&T is still in the NEC although permitted uses are very limited.

In Minnesota, State Farm put a surcharge on houses that did not have the
service replaced in some time period (don't remember what it was). They
were reversed by the state insurance regulator. There was no insurance
casualty data that supported the surcharge.

I would rather have K&T than some of the early 2-wire Romex type stuff
with tar-paper(???) jacket. Particularly embedded in insulation you have
2 wires together heating up instead of 1.
OK. The problem with K&T is mofifications.A house wired with K&T
usually had less than a 60 amp service with 2 or 4 circuits. Most of
those circuits were lighting cirguits - and MOST of the devices were
surfacxe mounted with no boxes. All connections were hidden (except
those in open basement ot attic structures) soldered and taped
connections. Shorts were uncommon because the wires are separated by a
minimum of 8 inches..

A lot of the buildings were also "ring topology" - both live and
neutral had both ends connected to the panel. (Not all - but a
significant number)

Adding "modern" loads required adding to the wiring - and how THAT was
done is the important elephant in the room. If the K&T is not touched
and new romex circuits are added FROM THE PANEL it is not a problem.
The right way is a new panel with the existing K&T panel set up as a
sub panel - and otherwise NOT TOUCHED!!!.. When new lighting fixtures
etc need to be added, run new circuits from the new panel according to
current code. Decommission the circuits no longer used.

Tapping into the original K&T in ANY WAY will generally trigger a
fail under an electrical safety authority inspection - as will
ANYTHING other than lighting circuits on K&T. It is a safety and fire
safety issue as virtually NO living electrician is competent in K&T
technique and the old rubber/cloth insulation doesn't respond well to
manipulation.

My Dad was an electrician and did a LOT of renovation wiring in older
homes and saw a LOT of extremely badly done "modifications" to K&T
systems - and had to remedy the problems caused including complete
rewires of houses where the modified K&T had not QUITE managed to burn
the house to the ground.