Knob and Tube Reporting

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1

Originally Posted By: jmichalski
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Having just seen my fifth house this week with the older cloth insulated wiring, it occurred to me to find out if anyone has a standard blurb (hopefully at least a little educational in nature) that they include when they encounter this.


I attempted to do a search for knob and tube and reporting, but didn't find any info. Forgive me if this has been covered already!

I would be grateful for a little something that would educate clients (so they don't freak out about older wiring in cases when it is not warranted) and also cover my bases (in a legal sense). Any thoughts?

2

Originally Posted By: Greg Fretwell
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If you are talking about the cloth Romex it should be as good as anything you see, assuming no rat bites or other physical damage. The other issue is the 60c insulation. In normal ambient air, even in hot attics that should be OK but in the canopy of an overlamped luminaire it can be trouble.


That is probably beyond your inspection tho.


I would be tempted to point it out anyway if I saw a 100w bulb in a ceiling light, labeled for 60 or a label that says 90c conductors only. That wire will probably crumble when you touch it.

3

Originally Posted By: rcooke
This post was automatically imported from our archived forum.


jmichalski wrote:
Having just seen my fifth house this week with the older cloth insulated wiring, it occurred to me to find out if anyone has a standard blurb (hopefully at least a little educational in nature) that they include when they encounter this.

I attempted to do a search for knob and tube and reporting, but didn't find any info. Forgive me if this has been covered already!

I would be grateful for a little something that would educate clients (so they don't freak out about older wiring in cases when it is not warranted) and also cover my bases (in a legal sense). Any thoughts?

Make sure it has a ground wire if it has I agree with Greg no big deal .
No ground recommend upgrade to a grounded system .
If it is on second floor and major work to this section .
Legal in Canada is to install a GFCI to protect all down stream outlets.

--
Roy Cooke Sr.

http://Royshomeinspection.com
4

Originally Posted By: mboyett
This post was automatically imported from our archived forum.


See the last question on the second page of this link: http://www.creia.org/technical/pdf/nov2004_locked.pdf


It’s a locked pdf file so I couldn’t cut & paste but it may be of some help.

–
Mike Boyett


Capital City Inspections


Austin, Tx


www.capcityinspections.com

5

Originally Posted By: srowe
This post was automatically imported from our archived forum.


A: Try the following: ?Much of the wiring in the home for


the most part is knob and tube wiring This type of wiring


is commonly found in older dwellings. Porcelain knobs are


used to secure the wires and porcelain tubes are used insulate


the wires as it passes through the framing members. Many of


the circuits are ungrounded. Knob and tube wiring in attics


should not be buried or covered with insulation unless the


system has been inspected and certified by a licensed


electrician. Removal of the knob and tube wiring and


replacement with modern wiring should be considered as


renovation projects are undertaken?. For buried knob and


tube wire: ?Some /much of the knob and tube wiring in the


attic is covered with insulation. This type of wiring is


commonly found in older dwellings. Porcelain knobs are used


to secure the wires and porcelain tubes are used insulate the


wires as it passes through the framing members. Many of the


circuits are ungrounded. This type of wiring was designed to


dissipate heat through the air. Knob and tube wiring in attics


should not be buried or covered with insulation unless the


system has been inspected and certified by a licensed


electrician. It is recommended further evaluation of the wiring


by a licensed electrician to certify it being safe and


dependable. It is also suggested that the wires be left exposed


at all times. Removal and replacement of the knob and tube


wiring should be considered as renovation projects are


undertaken.?. ❖

6

Originally Posted By: Steven Brewster
This post was automatically imported from our archived forum.


It has been my experience that some insurance companies will not insure a home that has active knob & tube wiring. I always recommend contacting their insurance agent to determine coverage.

7

Originally Posted By: Steven Brewster
This post was automatically imported from our archived forum.


http://www.oldhouseweb.com/stories/Detailed/10327.shtml

8

Originally Posted By: mboyett
This post was automatically imported from our archived forum.


Thanks for cutting/pasting that Shawn. Just out of curiosity, how did you do that? Do you have the full Adobe s/w or is there a trick for editing locked pdf files?

–
Mike Boyett


Capital City Inspections


Austin, Tx


www.capcityinspections.com

9

Originally Posted By: srowe
This post was automatically imported from our archived forum.


PDF Password Remover


http://www.verypdf.com/pwdremover/index.htm

Very handy utility , especially for codes and public documents.

10

Originally Posted By: mboyett
This post was automatically imported from our archived forum.




OK, here is what I come up with after a little word-smithing. You may be able to do better:


General statement: Much of the wiring in the home for the most part is knob and tube wiring. This type of wiring is commonly found in older dwellings. Porcelain knobs are used to secure the wires and porcelain tubes are used insulate the wires as it passes through the framing members. Many of the circuits are ungrounded. Knob and tube wiring in attics should not be buried or covered with insulation unless the system has been inspected and certified by a licensed electrician.
For buried knob and tube wire: Some /much of the knob and tube wiring in the attic is covered with insulation. This type of wiring is commonly found in older dwellings. Porcelain knobs are used to secure the wires and porcelain tubes are used insulate the wires as it passes through the framing members. Many of the circuits are ungrounded. This type of wiring was designed to dissipate heat through the air. Knob and tube wiring in attics should not be buried or covered with insulation unless the system has been inspected and certified by a licensed electrician. Removal of the knob and tube wiring and replacement with modern wiring should be considered as renovation projects are undertaken.
Add for either scenario: I recommend further evaluation of the wiring by a licensed electrician to certify it being safe and dependable. It is also suggested that the wires be left exposed at all times.

--
Mike Boyett
Capital City Inspections
Austin, Tx
www.capcityinspections.com

11

Originally Posted By: John Steinke
This post was automatically imported from our archived forum.


The issue of older wiring methods (knob & tube, cloth covered NM without a ground, etc) comes up from time to time. When it does, it is usually in the context of someone new discovering it for the firs time.


Being "old" is not necessarily a bad thing- nor do "old" things have to be "improved" or "updated." The actual problem presented is far more subtle than that!

As an example, I can use my house. Built in 1940 with knob & tube wiring, I am quite happy with my 30 amp, two fuse, 120 volt service. Both of my circuits are fused at 15 amps- and I have no problems with that! All of the wiring is in good condition; not even the wires at the devices have been damaged by over-heating!
Yet, I recognize that most folks would find this house unsatisfactory. For one thing, it is small. It has nowhere near the number of receptacles that many would find necessary. Laundry circuit? Yea, right....too bad the main drain line is only 1 1/2" pipe, too small to comply with the plumbing code requirements!

Even if the wires were completely lacking in insulation, they would pose little immediate risk- since they are kept a foot apart from each other, until they arrive at a device. And the Fuse industry will certainly argue that fuses are superior to circuit breakers in protecting the circuits from overload!

So, the HI first must learn not just how things are made today, but how they were in the past.
When he finds something that he considers old, dated, inadequate, obsolete -pick your adjective- he must then know what else to look for. Were there half-baked attempts to "improve' or 'upgrade' things? Were things pushed a little too hard, too long, before they were 'fixed?' Consider "age" as an indicator that you need to look for certain problems.

With a Knob & tube system, the first thing to look for are three-prong receptacles. Kind of hard to have a ground- regardless of what the little tester might say. Are the correct size fuses in the box (according to the wire size)? Are additional wires/ circuits added to the original? Are the wires at devices- especially above lights- showing flaking insulation, a sign of overloading? Have receptacles been added properly? Are other wiring methods (such as new yellow NM) also present? These are signs of other, more serious problems.

K&T is not inherently bad; the attempts to "fix" it are where the problems lie.

12

Originally Posted By: rcooke
This post was automatically imported from our archived forum.


mboyett wrote:
Excellent, thanks Shawn!
OK, here is what I come up with after a little word-smithing. You may be able to do better:

General statement: Much of the wiring in the home for the most part is knob and tube wiring. This type of wiring is commonly found in older dwellings. Porcelain knobs are used to secure the wires and porcelain tubes are used insulate the wires as it passes through the framing members. Many of the circuits are ungrounded. Knob and tube wiring in attics should not be buried or covered with insulation unless the system has been inspected and certified by a licensed electrician.
For buried knob and tube wire: Some /much of the knob and tube wiring in the attic is covered with insulation. This type of wiring is commonly found in older dwellings. Porcelain knobs are used to secure the wires and porcelain tubes are used insulate the wires as it passes through the framing members. Many of the circuits are ungrounded. This type of wiring was designed to dissipate heat through the air. Knob and tube wiring in attics should not be buried or covered with insulation unless the system has been inspected and certified by a licensed electrician. Removal of the knob and tube wiring and replacement with modern wiring should be considered as renovation projects are undertaken.
Add for either scenario: I recommend further evaluation of the wiring by a licensed electrician to certify it being safe and dependable. It is also suggested that the wires be left exposed at all times.


You might want to add at this time many Insurance companies will not give insurance .
Some who give insurance charge a premium.
In the future you could run into a time when insurance is no longer available.
Please check with your insurance company so see if insurance is available and what the cost could be.

--
Roy Cooke Sr.

http://Royshomeinspection.com
13

Originally Posted By: phinsperger
This post was automatically imported from our archived forum.


ESA_article_knob_and_tube.pdf )


This article was prepared for the Ontario Bar Association by Judith McTavish of The Electrical Safety Authority





http://www.aicanada.ca/e/pdfs/Spring2002%2029-40.pdf see last 3 pages
Although I agree with the article;

1) It does not mention the life expacncy of the insulation under nomal load conditions.

2) It does not talk about how K&T was desinged to be installed in free air and since that time many spaces have had insulation added covering the K&T.


What to buy some new knob & tube? http://www.sundialwire.com/index.asp?PageAction=VIEWPROD&ProdID=18

--
.


Paul Hinsperger
Hinsperger Inspection Services
Chairman - NACHI Awards Committee
Place your Award Nominations
here !

14

Originally Posted By: lkage
This post was automatically imported from our archived forum.


phinsperger wrote:
2) It does not talk about how K&T was desinged to be installed in free air and since that time many spaces have had insulation added covering the K&T.



A lot of interesting reading out there, eh Paul?

This article, put out by CREIA this year says that the Californis Electrical Code has been amended to allow insulation in contact with knob and tube provided 6 conditions are met.

Look here (page 2 Thermal Insulation): http://www.creia.org/technical/pdf/knob_tube_locked.pdf

--
"I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei
15

Originally Posted By: phinsperger
This post was automatically imported from our archived forum.


Nice article Larry. I saved it to my K&T file. Thanks


Interesting that the article says that K&T was designed to be in free air and then none of the 6 conditions regarding burying it in insulation address heat dissipation. Kind of sounds like "if you burry it we know its going to start a fire so don't anything flammable" ![icon_rolleyes.gif](upload://iqxt7ABYC2TEBomNkCmZARIrQr6.gif)

--
.


Paul Hinsperger
Hinsperger Inspection Services
Chairman - NACHI Awards Committee
Place your Award Nominations
here !

16

Originally Posted By: bkelly2
This post was automatically imported from our archived forum.


Quote:
The residence is wired with suspect knob-and-tube wiring, which should be evaluated by an electrician and certified as being safe or replaced


I do not have the time, expertise, or insurance coverage to check the entire electrical system to determine if the old obsolete wiring is safe. But I believe I should convey to my clients that the system should be checked.

As for the spacing of wires being 12 inches apart, both squirrels and roof rats come in sizes larger than that. ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

--
"I used to be disgusted, Now I try to Be amused"-Elvis Costello
17

Originally Posted By: John Steinke
This post was automatically imported from our archived forum.


First of all, I want to thank all of you who were able to dig up published reports that reinforce my points- though I’d be leery of citing anything from a foreign country (different rules and legal system, you know!).javascript:emoticon(’icon_smile.gif’)


Smile


As to the availability of knob & tube components. Apart from their use being restricted by the NEC, it should be pointed out that it has been so long that anyone manufactured them that UL has withdrawn the relevant testing standards. Those are used parts.javascript:emoticon('')
Shocked