wiring question Knob and Tube

[mission_modern_and_more]

I just bought a new (old) house and I have a couple of questions. Our underqualified although state licensed (Wisconsin) inspector missed some extremely obvious Knob and Tube wiring which turns out to be half the house so I'm rewiring most of the house. The first question is:

Do I have to remove all of the dead knob and tube wiring?

The second question is:

I'm running armoured cable to the attic to replace the Knob and Tube and the cable is running in an open cavity between two bedrooms. Do I have to open the wall and secure this every four feet?

Thanks, Gavin

[RBM]

Disconnecting old wiring is fine. It can be left in place. You don't need to secure wiring fished inside of walls

[hallerb]

I would remove ALL the exposed knob and tube, even though its disconnected. Makes selling your home easier in the future/

if you can see it remove it!

[Deke]

I agree. That stuff is scary for most of us.

[Just Joshin]

imho:

Before you do anything, I would suggest you get a qualified electrician. Although you want to do the work yourself, you can pay him/her to show up now and then to help guide you.

As for your questions, I would remove the wire so no confusion later. With the securing question, I believe the NEC addresses this by allowing it be unsecured in areas where inaccessible with a remodel.

Check just in case. ;)

later,

tom @

[mm]

I would be impressed, and like it.

Just shows how old the house is. I like that.

BTW is an inspector unqualified just because he doesn't note K&T. AIUI, it's still legal. Does he fill out a detailed report, or is he only supposed to note violatons?

[Joseph Meehan]

Are you sure you want to replace it? Really. K&T is a very good wiring system. You would not put any new in, but assuming what is there has the capacity for what you need, why replace it?

Are you assuming that the inspector is bad because he failed to note K&T? To the best of my knowledge (limited as it is) K&T is legal as grandfathered in. There are times you do need to change it out, but I don't believe it is universally illegal.

[RBM]

House inspectors are not electrical inspectors. They usually note anything that needs attention or can cost you money to repair or upgrade. The good ones will recognize violations too

[cavedweller]

Agreed. Seems most of the impetus for replacement comes from anal insurance companies and their threat of policy cancellation.

[Steve Barker]

The K&T wiring is not necessarily something the inspector missed. Perhaps he just didn't see any problems with it.

Answers to your questions:

1. no
2. no

[Steve Barker]

It's worth $2 a pound if you burn the insulation off of it. That's one reason to remove it. So far, I've pulled about 50 lbs of copper out of the two houses I'm doing right now.

[Nate Nagel]

Wellllll... most K&T is not rated to have insulation blown around it, so that pretty much mandates replacement in exterior wall cavities, in my book.

nate

[RBM]

I'm sure insurance companies base their concern in part by statistical information regarding old wiring. The problem with K&T is that it's easily recognized as "old wiring" with little to determine its actual age, which dates anywhere from the late 1800's into the 1960's and in rare instances later. Rather then judge its present condition, it's easier to condemn it, as many people do largely out of ignorance. Armor cable of various types has been in use from just before 1900 and a variety of non metallic cables not long after that, neither seems to rate the same negative attention paid to K&T, which I'd attribute to the general inability to distinguish its age. Today, we use a grounded electrical system, and as none of these old wiring methods had grounds or at least adequate ones, IMO, it would make sense to install new wiring as the opportunity arose

[cavedweller]

Agreed as well. My recent experience was in response to an insurance company concern where their report had simply shown a check mark in the "Yes" box beside K&T wiring.

In my case, however, the service panel had already been upgraded to

200 A and current code wiring for the major circuits had been installed previously.

I requested, and paid for, a provincial agency (Ontario ESA) inspection and, on the basis of their assessment, had some relatively minor modifications made, including the addition of some GF outlets for protection.

The major concern was therefore only for the remaining lighting circuits.

[RBM]

Clearly K&T has issues, such as blown insulation, but I'm bothered by the knee-jerk reaction to it. Where's the checkmark on the insurance form for pre 1920 wiring of all types?

[hallerb]

some negativity is because of fires caused since the connections arent in boxes buried in walls..........

insurance doesnt like K&T because of increased fire risk from a system likely a 100 years old.

what other things do we own that last a 100 years?

[Steve Barker]

BUT only if he's going to insulate OR someone already did. The OP didn't mention insulation.

[Steve Barker]

My agent didn't even mention wiring. I'm sure most don't.

[Rick F.]

We have a rental property we bought back in '94 that was built in 1923 give or take and it came to us with nothing but K&T wiring and a whole host of other more serious problems such as really bad & leaking roof, plumbing that was leaking on both the hot-n-cold and sewer.. Anyway, we had to get hazard (big $$) insurance since nobody would otherwise give us a policy.. We quickly found that the majority of the house had been wired into a SINGLE K&T circuit and that had I fired up a larger sized microwave oven we probably would have started charring wires in the attic.. We ended up re-doing the entire wiring system and ditched all of it -- it was a major hack job! Once we faxed a copy of the county inspectors closed-out permit showing replaced plumbing, electric, etc -- we were able to get a good (and cheap) insurance policy that was >10x cheaper than the hazard variety.

YMMV!

[RBM]

I think that the point here is that your house's infrastructure was in poor condition and as such it's in danger of fire, flood etc. Age alone does not make wiring bad or dangerous. A house built in 23' could have wiring types other than K&T, which in a poorly kept house, could deteriorate as badly or worse than the K&T. In fact, in the book " Old Electrical Wiring" by David Shapiro, he writes there is evidence that K&T was used in the 1980's in New Orleans, in areas that flooded frequently, specifically because it held up under those conditions.