Insulation and Knob & Tube

Status
Not open for further replies.
K

kuda

Member
Is it a violation of the NEC to have blown in wall insulation around knob and tube wiring?

Thanks,
Kuda
 
Re: Insulation and Knob & Tube

Unfortunately, a lot of old homes are getting blown in insulation around K & T wiring. The insulation people either don't care or don't know. :(
 
Re: Insulation and Knob & Tube

An additional headache is created by this situation. The insulation makes upgrading the K&T a real nightmare later on. Especially the blown-in kind, in attics.
 
Re: Insulation and Knob & Tube

buck33k,

That's the idea. :) So you are left with two options: remove the knob and tube or don't insulate around the K&T.

As Charlie said, many homeowners and inulators are unaware of this code rule (or don't care), and insulate anyway, creating a very hazardous situation. Fires have been caused by this. :(

[ January 01, 2005, 12:08 PM: Message edited by: peter d ]
 
Re: Insulation and Knob & Tube

Does the NEC apply to all states, or can each state modify the rules?

If you are in violation of the NEC, what practical implications does this have? Once identified does it have to be immediately corrected/removed? Does it mean that the owners can not get homeowners insurance? Or is simply something that people look the other way and pretend it is not a problem.

If you are an electrician working on a house and you find this NEC violation, does it mean that you have to correct it (or refuse doing the job), or can you just fix the problem that you were asked to address (which may not have direct relation to the knoba and tube)?


Thanks,
Kuda
 
Re: Insulation and Knob & Tube

kuda,

In my experience, the answer to your question is a can of worms.

The local AHJ may or may not have regulations about how existing wiring in existing buildings is dealt with. There may not even be a local AHJ, depending upon the state of adoption of building ordinances and codes.
 
Re: Insulation and Knob & Tube

As a practical matter there is always an AHJ. It may be a government agent, a contracted inspector, a contractor, or the owner or owner's agent. Someone has to approve the work, and as a practical matter that is the AHJ.

It does not mean that the AHJ is necessarily compentant to make the determination that the work is satisfactory.

Personally, I am scared of K&T wiring and think that in most cases it should be deenergized and new wiring installed. I also think the code should prohibit any connections to or extensions from existing K&T wiring. I am surprised that the insurance companies will even insure homes with K&T wiring given the serious problems it has over the life of a home.

When my folks bought their first house, the VA would not insure the mortgage until the house was brought upto code. Back then (1971) it meant putting in a bigger service (I think it went from 30 to 100A), and replacing a bunch of 2 wire outlets, and removing a bunch of outlets that had been installed in the floor. There were other things that I have probably forgotten.

Back then the city we lived in did not allow Romex except for remodeling, so all the new wiring was done in Romex, replacing what I now realize was probably K&T wiring in the new work, but leaving a lot of the old work in place.

Several years later we had a small fire on the second floor. Not real damage, just some smoke where some wires had melted their insulation. More damge from the fire dept response than from the fire, but it was K&T wiring and insulation ahd been blown in the attic and covered a light fixture. I guess it eventually overheated. IIRC, the insulation was required as part of the upgrades for the VA to guarantee the mortgage.

[ January 01, 2005, 01:16 PM: Message edited by: petersonra ]
 
Re: Insulation and Knob & Tube

I was involved in one of these k and t houses.It started out as a remodel/addition to a 1920's home in Tampa.When some walls and ceilings where opened the worms got out of the can.I found myself faced with insulated ceilings and some other not to code problems.The inspector was nice enough about it.He simply stated that if in the course of inspection he sees violations in old work that did not ever meet code that it must be corrected.The only cure here was to rewire the house and fix the other problems.I can't imagine anyone not fixing a fire hazard like insulation on k and t

I am surprised that insulation companies are not sued for the cost of rewire,or removal and payback the original bill for insulating.
 
Re: Insulation and Knob & Tube

I like the way you stated that, Jim.

I work in an area that has a lot of older building stock with a lot of K&T. Your inspector's approach is one I deal with all the time, in the inner city.

But when I get out to the edges of the city and beyond, it is not uncommon to find a very narrow set of blinders in the inspector's pocket (figuratively). I, as an electrician, am only responsible for what I work on. And it is the person who is buying my service that determines what I work on. Non-code installations will be talked about, but it is at the customer's discretion. . .even the installation that is a hazard has gray areas, as the list of what is deemed hazardous will vary from area to area.

As I work on the wiring of a building, I always inform the responsible party about safety and Code concerns. . .part of that informing is also including information about what the legal minimum requirements are.

It's a balancing act.
 
Re: Insulation and Knob & Tube

Originally posted by jimwalker:
I am surprised that insulation companies are not sued for the cost of rewire,or removal and payback the original bill for insulating.
Click to expand...
The last thing we need is for more litigation. The lawyers are already rich enough.

Educating insulation contractors is a good idea, and it would seem like the local building departments owuld be the place that education coudl start.

I am not all that convinced that it is the responsibility of the insulation contractor to tear apart the walls and see if there is anything there that installing insulation around might create a hazard. Anything out in the open like in an attic is another story.
 
Re: Insulation and Knob & Tube

If they looked in the attic they would know what kind of system it was.If they are ignorant as to codes involved with there trade then they should get sued and ran out of buisness
 
Re: Insulation and Knob & Tube

It sounds like no one likes K & T. Actually it is (was) a good system until it was asked to do more than it was designed for. It was installed in walls with a nice air cavity so that it had room to keep cool, it was on knobs, insulators, cleats, and placed in tubes and loom. It was fused for the current that was placed on it and it would have been good for the life of the home if not mistreated.

With the advent of pennies, insulation, and additional load, it was looked down on (with good cause). As far as grounding goes, it is generally a waste of time except where water is around. How many lamps do you see with a grounding pin? When replacing a light bulb, where do you find a ground to get into a position to get a shock? Most of the time, in a home, shock hazards do not exist except in the bathrooms, garage, crawl space, outside, etc. (basically where a GFCI is located).

Bottom line, K & T is OK as it was originally installed and in the original circumstances. :D
 
Re: Insulation and Knob & Tube

One of the problems with looking into the attic, even while applying new insulation, is that some insulation is already likely to be present and covering the K&T.

The Uses Not Permitted of Concealed Knob-and-Tube Wiring before 1987 did not concern itself with insulation. See 1987 NEC 324-4 and 1984 NEC 324-4 for the change.

Up in Minnesota, a lot of insulation started going in around WWII, by my observation. The energy crisis of the Early '70s added a lot more insulation.

Much of the K&T in contact with insulation is grandfathered in! :eek:
 
Re: Insulation and Knob & Tube

I don't think anything considered a life safety issue or fire hazart. is grand fathered in.
 
Re: Insulation and Knob & Tube

"Much of the K&T in contact with insulation is grandfathered in! "

That's sad to think that a homeowner was mislead into something dangerious and now will cost them more money.
Yes Charlie k & t was a great system and from what i have seen safer than the 2 wire cloth romex that followed.I wonder why we still run ground wires today when most everything has no ground prong and a gfci breaker or receptacle could offer more protection.Aiming that at homes with plastic boxes.There are still many homes using k&t and if left undisturbed could last another 100 years.Will our new romex last 100 years ?
 
Re: Insulation and Knob & Tube

I absolutely agree, Charlie.

My post is intended to illustrate the thicket of confusion around responsibility.

One of the hard and fast ethics seems to be
If I don't see it, I'm not responsible.
Click to expand...
Earth quakes are dangerous. California is on a major fault line. How many millions live there?

This goes to my point that, inspite of the danger, the individual is given the choice to do nothing. Until that choice is removed, there will be a lot of K&T that will be available for incremental improvements past 2105.
 
Status
Not open for further replies.
Top