K & T Question

[Fred B]

Other issue is a lot of insurance companies are taking such reports and canceling or refusing to write insurance on a building with K&T and for that matter even with old fuse panels, and requiring updating.

 

[jaggedben]

I really appreciate all the feedback. So, as a licensed electrician who has had this ball placed in my court, if the insulation was installed prior to 1987, there is no liability on me if I document the insulation was in place prior to the NEC ruling?

There's no liability on you for stating facts, as long as you stick to stating facts, which you know are facts. Is it your role to determine when the insulation was installed? Are you being paid to give an opinion on whether it is compliant or safe? Myself I would not take money for giving an opinion that it was safe.

 

[kwired]

The substantiation for the 1987 change said:

Weatherization of the hollow spaces by blown-in insulation or roll insulation prevents the dissipation of heat into the Free air space; resulting in higher (dangerous) conductor heat buildup, conductor insulation breakdown resulting in a probable or possible fire situation.

There was one dissenting vote and his statement said:

The substantiation to support this proposal does not contain the necessary factual data to support this restriction on concealed knob and tube wiring. There is a large number of installations of concealed knob and tube wiring. I have neither heard of any problems with this wiring method nor have I seen any studies on actual in service installations that will support this restriction on concealed knob and tube wiring.

I agree with the dissenting comment.

Possibly one of the the last times such a statement was made by a CMP member?
Been a lot of "because we can" related code changes since about 2002 NEC.

 

[kwired]

My brother worked for an agency that had enough fires after blowing in insulation around K&T, that they would not do it. Yes, most likely it was in poor repair. Does not matter. It happened.

No DIY's or handy man ever made a flying splice without soldering when tapping on to a K&T circuit some 30 or more years after the K&T install.

Original installs are actually pretty safe as a general rule it is those that tampered with it many years later that usually made it unsafe.

 

[Geber]

No DIY's or handy man ever made a flying splice without soldering when tapping on to a K&T circuit some 30 or more years after the K&T install.

This seems to me like sarcasm. Some of the people reading this board might not speak English as their first language, or be used to talking to electricians, and so might not understand sarcasm. Perhaps @kwired would like to clarify.

 

[ptonsparky]

This seems to me like sarcasm. Some of the people reading this board might not speak English as their first language, or be used to talking to electricians, and so might not understand sarcasm. Perhaps @kwired would like to clarify.

Sarcasm thru and thru.
or

 

[retirede]

No DIY's or handy man ever made a flying splice without soldering when tapping on to a K&T circuit some 30 or more years after the K&T install.

Original installs are actually pretty safe as a general rule it is those that tampered with it many years later that usually made it unsafe.

You left out the part about the 15A screw-base fuses being replaced with 30s.

 

[kwired]

This seems to me like sarcasm. Some of the people reading this board might not speak English as their first language, or be used to talking to electricians, and so might not understand sarcasm. Perhaps @kwired would like to clarify.

Well it is sarcasm.

Also this is a forum for electrical professionals though it is open to viewing by pretty much anyone.

If they don't like it there is always Electrician Talk where there is apparently no limits on sarcasm or offending other participants

 

[ptonsparky]

You left out the part about the 15A screw-base fuses being replaced with 30s.

So amateur. Pennies for the poor and dimes for the more affluent.

 

[electrofelon]

Not surprising to me. That seems to be an unfortunate trend with some of the CMP's.

Right , what I really meant was baffling how it's like a flip of the coin with them as to whether they will shoot something down for having no evidence vs just blindly accepting.

 

[curt swartz]

The California Electrical Code added this:

Exception: [HCD 1] This article is not intended to prohibit the installation of insulation where knob-and-tube wiring is present, provided the following are complied with:

1. The wiring shall be surveyed by an electrical contractor licensed by the State of California. Certification shall be provided by the electrical contractor that the existing wiring is in good condition with no evidence of deterioration or improper over-current protection, and no improper connections or splices. Repairs, alterations, or extensions to the electrical system will require permits and inspections by the authority having jurisdiction for the enforcement of this code.
2. The certification form shall be filed with the authority having jurisdiction for the enforcement of this code, and a copy furnished to the property owner.
3. All accessible areas in the building where insulation has been installed around knob-and-tube wiring shall be posted by the insulation contractor with a notice, clearly visible, stating that caution is required when entering these areas. The notice shall be printed in both English and Spanish.
4. The insulation shall be noncombustible as defined in the California Building Code.
5. The insulation shall not have any electrical conductive material as part of or supporting the insulation material.
6. Nothing in this exception will prohibit the authority having jurisdiction for the enforcement of this code from requiring permits and inspections for the installations of thermal insulation.

 

[tortuga]

There is a similar exception in Oregon. When I do k&t surveys for these weatherization upgrades I always require the following:

• k&t needs to meet article 394 (funny how hard this can be).
• Must have 15A AFCI/GFCI protection, if fuses are involved they have to be type s.
• Exposed splices or connections shall be protected from insulation by installing flame resistant, non-conducting, open top enclosures which provide three inches, but not more than four inches side clearances, and a vertical clearance of at least four inches above the final level of the insulation.
• Insulation shall have a flame spread rating not to exceed 25 and a smoke density not to exceed 450 when tested in accordance with ASTM E84-91A. Foamed in place insulation shall not be used with knob-and-tube wiring.
• No more than 400 SQFT of residence per k&t circuit (10A load @ 3VA per sqft)
• No more than 10% voltage drop @ 12A load (tested a farthest point with a Ideal 'sure test').
• No BX (or other metallic wiring methods) cable tapped off k&t.
• Short single wire repairs are done with single conductor UF.
• Hard wired smoke detectors required to current code.

 

[don_resqcapt19]

Possibly one of the the last times such a statement was made by a CMP member?
Been a lot of "because we can" related code changes since about 2002 NEC.

There are comments like that most every code cycle from various CMP members. Just because something is in the code does not mean that all of the panel members agreed to make that change. Just short of 1/3 of the members can vote against the change and it will still be in the code book as you need a 2/3s majority to make a code change.

 

[mtnelect]

The substantiation for the 1987 change said:

There was one dissenting vote and his statement said:

I agree with the dissenting comment.

This is my opinion, Do Not Disturb "Knob-and-Tube" wiring.

 

[A/A Fuel GTX]

There's no liability on you for stating facts, as long as you stick to stating facts, which you know are facts. Is it your role to determine when the insulation was installed? Are you being paid to give an opinion on whether it is compliant or safe? Myself I would not take money for giving an opinion that it was safe.

The house is 97 years old. The home inspector that cited the K & T never mentioned the attic space. He observed some K & T in the basement box sill that had some fiberglass insulation bats in contact with the K & T that was visible. Based on that, he mentioned that the wiring in the house be evaluated by a licensed electrician. So basically, he kicked the can down the road. That was the extent of his comments regarding K & T. I went into the attic to follow my suspicion that there probably was K & T up there as well. There was, hence my reason for starting this thread. It's very obvious that the insulation in the attic has been there for many decades based on the material used.

 

[mtnelect]

This is my opinion, Do Not Disturb "Knob-and-Tube" wiring.

Since I am also an HVAC contractor, I have seen a lot of Asbestos Insulation. As long as you don't disturb it, you can keep it, same for knob and tube.

 

[jaggedben]

The house is 97 years old. The home inspector that cited the K & T never mentioned the attic space. He observed some K & T in the basement box sill that had some fiberglass insulation bats in contact with the K & T that was visible. Based on that, he mentioned that the wiring in the house be evaluated by a licensed electrician. So basically, he kicked the can down the road.

I see. So you are being hired as an expert, not necessarily to do contracting work? Regardless, liability wise, I think it's still advisable to stick to stating facts. If you're going to provide evaluations regularly, you may also want to talk to your insurance agent about whether you are covered if you make any mistakes or whether you should get Errors and Omissions insurance. Of course your agent will likely try to sell it to you, but still.

That was the extent of his comments regarding K & T. I went into the attic to follow my suspicion that there probably was K & T up there as well. There was, hence my reason for starting this thread. It's very obvious that the insulation in the attic has been there for many decades based on the material used.

I would hedge all my findings with words such as 'likely' and never say 'very obvious' if you don't really know. And state clearly what makes you think it's been there many decades. Also state what you are unable to see without disturbing insulation (which I totally agree should not be disturbed unless/until there's a contract to replace everything).

 

[tortuga]

As long as you don't disturb it, you can keep it, same for knob and tube.

Unfortunately insulating around it is disturbing it, especially now as spray foam is hugely popular.

Speaking of HVAC thats where I see the most violations with k&t, where HVAC installers put metal ducts within 3 inches of it (394.19), or even pinching it. I have also seen it inside joist bays used for return air to a furnace.

Another problem I see is when EC's do a panel upgrade and use breakers over 15A (I have seen 20 and even 30's) its understandable they see a large AWG k&t wire at the panel and presume its all that size wire, when infact k&t was 'plumbed'. That larger wire only extends down the middle of a house, then tapped off it are 14 awg to the 'lighting outlets'. I have seen k&t wires as big as #8 (solid) run down the middle of an attic, this was becasue the original power source was a 32V or 120V delco DC generator (ungrounded system). Probably more common in rural farm houses as it took a long time for the grid to reach some places.

 

[LarryFine]

Isn't insulation the reason we have the 240.4D and 60-degree NM limitations?

Among other reasons. Meaning that these concerns have already been addressed.

 

[tortuga]

If your interested in some reading on the topic there is an old report here:

knob_and-tube-in_blownin : Building Research Council : Free Download, Borrow, and Streaming : Internet Archive

Report in installing cellulose insulation over knob-and-tube electrical wiring.

archive.org

To sum it up part of the issue is the flammability of the insulation, so knowing the ASTM E84-91A flame spread is important.