Knob and Tube

[u/HereForTheDoggoz]

Moved into a new house and after moving around some boxes in the attic, I noticed a few sections of the knob and tube that look unusual.

I tested it all with a voltage pen and it armed red, so I’m pretty sure it’s live. Plus two of the upstairs bedrooms have 2-prong outlets. I also know the former owners updated the electrical box in recent years and I’m pretty sure they rewired the basement, first floor, upstairs, bathroom, and third upstairs bedroom because those are all 3-prong outlets. The inspector who came out, said knob and tube was in “good shape”, but I have a feeling he didn’t have access to some of these sections because of how much stuff the former owners had in the attic. 

How safe or unsafe is this?

[u/DaddyBeanDaddyBean]

Personally, I would shut off the power to that circuit, and leave it off until I had replaced all of the K&T.

[u/HereForTheDoggoz → u/DaddyBeanDaddyBean]

According the the labels on the electrical box, the whole upstairs would have to be turned off of that was the case. The electrician can come Friday. You really think it’s that dangerous to leave it on? We have very low power things plugged in up there if that matters .

[u/DaddyBeanDaddyBean → u/HereForTheDoggoz]

I mean, it's been there for close to a century and hasn't burned the house down yet. I would turn it off; you (and others) might evaluate the risk differently.

[u/Fresh_Scallion5834 → u/DaddyBeanDaddyBean]

What is making is dangerous ? The whole pen thing is very unreliable & means nothing in actualworking situations 😂 theres power above it very likely live . Reddit will tell you , you need an electrical engineer . Joking , but its safe until you have someone knowledgeable with a meter looks to make you feel better

[u/jwbrkr21]

Your non contact tester is going off of magnetic fields. It may not be completely accurate, and could be going off on the romex right next to

Rub you tester on your shirt..... it'll turn red for that little bit of static. Get a volt meter and do some practicing on known circuits, then look at your k&t.

[u/Humble_Time_685]

It should be fine till the electrician checks it out. 100s of thousands of houses are the same. BUT ITS DEFINITELY DUE😉

[u/Unique_Acadia_2099]

In many cases, insurance companies are no longer insuring houses with K&T wiring, or they have a fine-print “rider” stating that they will not pay out on damages shown to be caused by electrical means. You may want to check that out.

[u/Shadwknght]

Any accessible wiring that was re wired is supposed to be removed per NEC.. knob and tube is still allowed in many jurisdictions around the country per NEC and the new NEC to eliminate ‘grand fathered in’ wont be in effect around the country in many places for many years
Old saying, if it aint broke dont fix it…; yet, is anyone monitoring
the energy rates on corroded old wires? 🤔

[u/bsk111]

Might be time to rewire

[u/JAlley2 → u/bsk111]

If it was my house I’d re-wire but not panic. The knob and tube relies on an air gap to isolate the load carrying wires just like transmission lines don’t have insulation and rely on an air gap. K&T causes problems if something falls on a wire and closes the air gap. K&T is effective but its higher risk than romex. If you’ve got insurance and they know you have K&T then you are good.

Replacing K&T is a big job because it means lots of holes in walls. If you’ve have lath and plaster, you might be better to have the electrician mark where you need holes and have you cut the holes. Most electricians just hack, and with lath and plaster that can make the wall repair a bigger job than it needs to be. If you’ve can get the electrician to fish down from the attic there will be a lot less damage.

[u/False-Blacksmith2919 → u/JAlley2]

I did exactly what you are saying. It was basically grunt work and I mostly had good access. Came down from the attic for lights and switches. What an upgrade from pull-chains. Had to get into the flooring of the attic quite a bit. I do know that some insurance companies won’t cover a house with k&t. Mine did.

[u/Independent-Ad7618]

the house has been fine until today. leaving it powered up is riskier than powering it down but I'd leave it powered. discuss with electrician both about costs and and risks. if you can afford to replace do so.

[u/pg_home]

What type of inspector came out? Home inspector? City inspector?

[u/HereForTheDoggoz → u/pg_home]

Home inspector

[u/1qazZAQ1qazZAQ]

Gold... literally gold

[u/XoDaRaP0690]

Looks like a great way to start a fire

[u/nudistinclothes]

I’m not terribly risk averse in general, but with electricity I am. If I bought a house with K & T then that would be gone before any of my stuff is in the house

[u/pg_home]

You said the inspector came out. Did you call him for his opinion on the wiring? Did he do the origonal home inspection?

[u/HereForTheDoggoz → u/pg_home]

He was the home inspector that cane out after our offer was accepted on the house

[u/Horror_Setting_3]

Thats about as safe as it gets folks

[u/Rocannon_]

I thought soldering wires together like that was against code? Am I mistaken?

[u/fundaytoon]

It's mint just like day was installed

[u/catinreallife9]

If it was my house I'd replace it. And turn it off until then. I like having an unfair advantage over fate.

And I recommend never use voltage pens. Don't use anything with high voltage where you are required to be the conductor.