Is Knob-and-Tube *Always* Dangerous?

I'm sure this question has been posted and answered a thousand times here, but a family member who routinely asks me to walk-through homes she is interested in buying (because, as a walking Typhoid Mary of Money Pits, I have hard-earned knowledge) has asked me to jump on a particularly desirable (location, location, location) multi-unit this AM.

One half of this duplex has knob-and-tube.

I have read conflicting estimates of the integrity and safety of knob-and-tube on this group and other web sites. But I'm scheduled to go through the home in two hours and thought I'd post and maybe get some fresh insights.

From the street, and as far as the exterior foundation goes, this home

is an absolute steal (new roof, great landscaping, has it all). My family member needs a place to run to as the result of a divorce and won't be able to take on both the mortgage and a complete rewire at the time of sale; hence, my post.

Thank you as always for your responses.

Reply to
pennsylady2002
Loading thread data ...

knob and tube is ungrounded, as was lots of Romex installed in the 50's and

60's . In some places its unprotected and subject to mechanical damage. The stuff is OLD, but in my experience, most of the K&T I've seen, has been in excellent condition, unlike rubber covered conductors of BX cables from the 40's and 50's, which breaks down and crumbles from heat. I would ultimately replace it, but I wouldn't feel in any hurry to do it yesterday

Reply to
RBM

Knob and tube is not, by nature, dangerous. It happens to be a very save system The real problem is it is no longer used and has not been used for a very long time. Therefore it is not up to modern expectations, like having a ground or being able to supply a good size room A/C unit.

You need to check with local codes, including those that may only apply to rental property to determine if you need to do any replacement. Likely, and logically, if you are doing work in an area and it is convenient to replace the K&T at that time, you should. Don't mix it on the same circuit for example.

Stick to code and you will be safe.

Reply to
Joseph Meehan

probably CANT get homeowners or a mortage with K&T most insurance wouldnt cover it as a fire hazard.

connections are soldered in the wall, without a box surrounding it. unlike today all coinnections are in boxes.

after many years and heavy loads the solder weakens and the connection can overheat and cause a fire, that happened to a buddy of mine fortunately in his open basement cieling he smelled smoke and put it out.

in a closed wall the house will go up in smoke.

have friends whos homeowners inspected their home and REQUIRED rewiring for just this reason.

deduct cost of rewire from home sale price and for futher savings get a home inspector they arent perfect but every trouble they find is money in your pocket.

call your insurance agent and ask about K&T and please report back here what they tell you...

K&T would be safe IF the connections had been made in BOXES but back then no one thought of it

Reply to
hallerb

The deciding factor is not whether it is dangerous, which it rarely is unless it's been messed with, but rather whether you can get insurance for the place with K&T. Most insurance companies are absurdly paranoid about K&T and indeed any electrical older than about 30-40yrs.

Pete C.

Reply to
Pete C.

Reply to
kv888831393ster

Pete nailed it. Start with a call to Insur agent.

Jim

Reply to
Speedy Jim

The only way that the solder will fail on Knob and Tube wiring is if the circuits were fused with improperly sized fuses. If the circuits are protected with properly sized fuses K&T will last for decades.

Reply to
Tom Horne, Electrician

OBVIOUSLY you dont know enough about solder, over LONG times it wiskers and detoriates. now K&T is likey 50 years old or more, and quality of metals and solder wasnt great way back then.

I fix office machines for a living, at one time did tv and other appliance repair. in that time every now and then would find a bad solder joint, that had workewd forever. frequently in low power circuits where it wasnt and couldnt be overloaded.

Insurance doesnt like K&T because it cost them too much in fire losses,,,,,,,

otherwise they wouldnt care!!

you go right ahead thinking K&T is safe, all those insurancer companies just dont know what they are talking about:(

Reply to
hallerb

No. Fuses and circuit breakers prevent that.

Nick

Reply to
nicksanspam

Below are a couple of links to consider wrt knob & tube wiring. Although my experience is limited, the times I have seen crumbling wire insulation with K&T is where it joined ceiling light fixtures, and that was because of the heat (over heating) due to the fixtures.

In some such cases it was possible to (properly) solder a replacement extension onto such a wire and then use a sleeve to cover that, followed by the installation of a junction box to hold the wire safely in place and connect to the fixture.

Whenever possible I replace K&T, but when not reasonable to replace, I would be sure the circuit is on a 15A max breaker. Usually receptacles, which is where the greatest loads exist, and where a ground is especially desirable, can be more easily rewired with romex.

formatting link
These links are especially interesting and deserve a full reading. My comments are just my own opinions and ideas. --Phil

Reply to
Phil Munro

Since the days of knob-and-tube, a lot of experience has been gained from a safety standpoint. Many changes have been made to the electrical code which make things a whole lot safer. And the safety aspect means protection of life and property.

Over the years there have been fires and people electrocuted for this or that reason. Then the electrical codes have been changed to prevent these things from happening in the future.

With that said, the safest thing to do would be to re-wire the house to the latest electrical codes.

Also many years ago they did not have the electrical needs we have today. So there is the daily pain in the you know what factor. Not enough outlets, many rooms on one circuit and not enough capacity. Old outlets where you need to jiggle the plug in the outlet to get it to work, etc.

Having all new grounded wiring and plenty of outlets/capacity can make day-to-day living a whole lot more pleasant. It's nice to have outlets where you need them and not need to jiggle the plug to get it to work.

Reply to
Bill

No, its not always dangerous. As Joseph said, its not inherently dangerous.

Here are circumstances when it is dangerous.

- When a ground is needed by a device and its not available.

- when it has been extended or hacked onto by somone not knowing what they are doing

- when the fuse has been "upgraded" to a larger one because it kept blowing

- Then the wire is overloaded

Remember - when it was installed there were no hair dryers, electric curing irons, air conditioners, PCs, microwaves, etc.

It becomes unsafe when people try to add on more outlets to accommodate these things.

Reply to
No

I won't disagree, but will point out that it has been in place for decades- at least 6 of 'em, if not more.

D
Reply to
spamTHISbrp

snipped-for-privacy@gmail.com in news: snipped-for-privacy@m79g2000cwm.googlegroups.com:

never seen that, maybe that's the older knob and tube. i've seen 50's stuff that was connected properly in boxes with the short piece of "loom" thru box holes. (as well as i recall)

i've also seen separate ground wire for old two-conductor romex (kitchens) that had twisted and soldered connections. i guess if ground wire went into rare effect (lots of current) accumulated debris in wall could light up.

older houses had no insulation, so if adding insulation, i think you'd have to replace wiring or guess (!hahahaaaaaa) at how far to derate current for knob and tube.

Reply to
Choise76Smu

One problem with K&T is that whatever the condition of the original material, it's seldom properly connected to more modern wiring:

formatting link
and every incorrect junction is a potential problem.

Another is that users may overload K&T circuits - a single K&T circuit often serves potential loads that would be split between multiple circuits in a more recenly installed system. In my area it's not unusual to find a single K&T circuit powering all the lights and receptacles in three or four bedrooms and a bath on a top floor, but power demands have increased (no window ACs back then!) and users many be tempted to "overfuse" such circuits in an attempt to supply sufficient power to loads at multiple locations on a single circuit.

So depending on the situation, when you have electrician throughly inspect a K&T installation and identify existing defects you will often find it's also desirable to pull additional circuits to meet modern demands - in which case it's likely not all that much more expensive to bypass the K&T with new circuits entirely.

Michael Thomas Paragon Home Inspection, LLC mdt@paragoninspectsDOTcom

847-475-5668 .
Reply to
MDT at Paragon Home Inspection

Insurance KNOWS its fire hazard rate is higher, and buying a preowned home its possible others did unsafe changes to the wiring.

Things DONBT last forever and K&T is just another thing.........

solder can and does fail over time espically if anyone used acid flux when making repairs, its great for plumbing but unsafe for electrical wires.

if your defending K&T please state if your home has that wiring..... thanks

Reply to
hallerb

Hi, I'm not defending K&T and I do not own any property with it. I was just pointing out what makes it unsafe. Realities of todays lifestyles with everything electronic and AC in every room make it very likely that K&T has been scabbed on to and over loaded. Thats what makes it unsafe. If K&T were just used for a couple of overhead lights and wall socket for a lamp and never was over loaded and the fuse was of a proper size, and always has been, then I would not be concerned.

If, as I stated, it has been messed with, added on to, over loaded, a larger fuse used, remodeled around, etc. I would not be comfortable with it.

So, most likely its unsafe or someone will make it unsafe my replacing a

15A fuse with a 30A fuse, swapping an outlet for a grounded outlet without hooking up the ground then running their window AC, hairdryer and PC off of that outlet. Thats when it becomes unsafe.
Reply to
No

Fuses and breakers protect against overcurrent situations - not overheating due to deteriorating connections.

Bob

Reply to
Bob

Mine does. In an english-style loop around the attic, feeding the attic lights, and drops to all the outlets on the second floor.

It hasn't burnt down yet.

As long as you remember that you've got a

60 year old wiring system, and don't abuse it, it should be fine. When you GET the chance to replace it you should, but it shouldn't be a deal-breaker on an otherwise good house.
Reply to
Goedjn

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.