On 5/26/2021 10:03 PM, Clare Snyder wrote:
On Wed, 26 May 2021 10:09:21 -0600, bud-- wrote:

On 5/25/2021 11:01 PM, Clare Snyder wrote:
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

The US does not require "lighting circuits". K&T powered whatever was
installed at that time.


And MOST K7T installations had very few "outlets" - mostly lighting -=
untill the last decade or 2 of it's use.

So "few outlets" not "lighting"? Null and void in the last decade?
As I wrote, you are unlikely (here) to find a K&T installation that does
not have a new service and added wiring including receptacles.


- and MOST of the devices were
surfacxe mounted with no boxes.

Maybe where you are. I have seen a lot of K&T and NEVER seen that.

K&T very seldom used boxes in original installation

Nice to know you are an expert on US wiring practice. Sorry about the
sad state of Canada.


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..

Wiring in open basements is "open wiring on insulators"

As it is even within walls and enclosed floor / cieling

If you read the post from g, if enclosed it is K&T. "Open wiring on
insulators" is another NEC type of wiring. No penalty for this one - it
is esoteric NEC.



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)

Ring Topology was relatively common in EARLY K&T. Not so common in
later years

Irrelevant because it was not used in the US.
Or is Mickey Canadian? (That might explain some things.)


That may be how you do it. It is common in the UK. Maybe the queen told
your electricians to use ring circuits.

I have never even heard of that in the US.


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!!!..

A subpanel just for K&T is another nutty Canadian idea? Also never seen
that. Existing K&T is just refed from a new service panel.

No, not nutty, and not Canada specific. And I am not talking about
"adding" a sub panel. I an talking about using the existing K&T panel
AS a sub panel to avoid mofifying / disturbing the K&T circuits, since
that is where any problems are likely to happen.

Apparently Canadian electricians are not be qualified for "modifying" K&T.
I haven't had a problem.

My mother's house had the original K&T service on the 2nd floor. Feeding
it would require running a feeder from the basement service panel into a
wall on the 2nd floor. You then have fuses on the second floor in
addition to the service panel in the basement. The electricians who
installed the new stuff had no problem feeding the K&T where it was
exposed (fortunately they were not Canadian). I have never seen an
original K&T panel refed. And the 2 panels I remember had exposed
terminal screws on the fuse blocks- an inspector would love that.


The NEC allows "extensions of existing installations". (That is probably
uncommon.)

It ALLOWS extentions - but they have to be done properly - and when
the cloth / rubber insulation deteriorates doing ANY modifications
gets dicey. Just because code "allows" it does not make it adviseable.

You have convinced me. Canadian electricians should not even be in a
building with K&T.


My mothers house had K&T. I survived in it for 20 years (Perhaps a
miracle??). At some point she replaced the service with a 100A fuse
panel and added some receptacles and other wiring. That is likely very
common. If a house has only original K&T wiring the Smithsonian museum
is probably interested.

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.

So lighting fixtures can't be replaced? Or is this just new wiring,
where lighting is not unique (except apparently in Canada).


If there is no box it is against code to mount fixtures requiring a
box. Adding a box to a K$T circuit that does not have a box is
problematic at best

No boxes is another Canadian thing?

- particularly if / when the wire from the old
fixture is roasted / toasted / sun-tanned and crispy fried.

The most toasted wires I have seen were not K&T and were behind
Circline fluorescent fixtures.

Maybe there was a problem with Canadian wire?


Tapping into the original K&T in ANY WAY will generally trigger a
fail under an electrical safety authority inspection

The NEC allows "extensions of existing installations".

- as will
ANYTHING other than lighting circuits on K&T.

But now you said "few 'outlets' - mostly lighting". So original
installations will fail because of the "few outlets". And all will fail
if installed in "last decade or 2 of it's use".


The US does not require "lighting circuits". K&T powered whatever was
installed at that time.

It is a safety and fire
safety issue as virtually NO living electrician is competent in K&T
technique

I guess I am not a living electrician. Minor changes are not that
difficult (like refeeding, which is common with a new service).

and the old rubber/cloth insulation doesn't respond well to
manipulation.

Rubber I have seen is generally in good condition. Original wiring in my
house is rubber (in rigid conduit).


Only in the USA I guess. Rigid conduit in residential wiring is
virtually unheard of in Canada.

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.

My kid's house had a lot of "extremely badly done" wiring. There was no K&T.
So argue about wiring of any type that is in bad condition.

As I wrote I have more concerns about the early 2-wire stuff before Romex.

I have heard of no data that says K&T is intrinsically a particular hazard.

It isn't - and I didn't say it is. I SAID shorts are almost unheard
of due to the spacing of the wires. Unmolested K&T IS SAFE - but
seldome actually found "in the wild"

Canadian electricians are molesters?
Insurance prohibition is not based on whether K&T is molested.

I haven't seen many K&T problems. Again, sorry about the sad state of
electric in Canada.

I'm sure you will be surprised to hear that I have seen other wiring
systems that have been molested.


Note the court ruling and multiple states allowing insulation around K&T.

Again, just because it is ALLOWED does not make it wise

It was allowed because there was no record of a problem.

I don't think Chicago went far enough requiring EMT. All wiring should
be rigid conduit. Who needs facts.


And the NEC is trying to put most EXISTING residential circuits on AFCIs.

So???

Removes a lot of the risk from wiring problems (K&T or other).
Insurance requiring K&T to be on an AFCI would make some sense, but that
would defeat redlining.


Also 2-wire circuits can be connected downstream from a GFCI.

So???

One of the complaints about K&T (miraculously missing in this thread) is
that it does not include a ground wire. Downstream from a GFCI
eliminates most of that problem, and the NEC allows grounded type
receptacles downstream from a GFCI when there is not a ground.


Are you a professional electician ??

Master electrician.

I am not fond of K&T. I have just not seen where it is a lot more
dangerous than some other methods like, as I have said, the early 2-wire
pre-Romex. And you agree "unmolested K&T IS SAFE". K&T, like all
methods, can be abused. I don't think insurance or mortgage restrictions
are based in safety. Replacing it, unless you are doing a gut-rehab is
real expensive.

And looking at the 3 summarized points to g on insulation, I don't
think the NEC insulation restriction is based on facts or data. I am
sure g is shocked to think code panel decisions are not based on facts
or data. Well, maybe not "shocked"...