Old knob and tube tied into romex (is it live?)

Here you'll find a wide range of discussions on old-house topics.

Moderators: TinaB, Don M, Schag, oldhouse

Old knob and tube tied into romex (is it live?)

Postby prairiebox » Fri Apr 10, 2009 11:07 am

Last fall I opened up about 30" of wall to enlarge a closet door opening. The wall was original plaster (I literally cried as I broke out the plaster :oops: ), and didn't look to have ever been messed with. Inside the wall was some old knob and tube wiring. Except about 5.5' up, where there had been a light fixture attached to the other side of the wall, and some genius had spliced in romex with electrical tape. Here's the best picture I can get without touching it (I'm scared!):

Image

The silver romex runs straight up and disappears into the attic somewhere. The attic is full of blown-in insulation, and we haven't been brave enough to go digging. But, with out limited knowledge of electrical, we can't figure out where the romex might lead. There are no fans up there, and there are no outlets/switches/fixtures near the k&t/romex splice. The wall is not load-bearing, so there is nothing below, except the dining room ceiling.

Down in the basement, we have a circuit breaker box, and the rest of the house has updated electrical (supposedly). All of the visible wiring is new, plastic coated wire, not the silvery braided stuff like what I found in the wall.

So... Given my limited info, what is the best way to determine whether this wire is live or not? My gut feeling says that it probably isn't, but at the same time, that romex has to go somewhere. Is the attic the best place to start looking?
Image Visit my American Foursquare at http://prairiebox.blogspot.com
prairiebox
 
Posts: 337
Joined: Wed Aug 17, 2005 2:01 pm
Location: South Bend, IN

Re: Old knob and tube tied into romex (is it live?)

Postby HouseNut » Fri Apr 10, 2009 12:10 pm

I'm sure there are electricians here that will have a lot more to say but I'd start with 'be careful'. lol

There was a house we looked at here last year that had 'romex'.... or at least appeared to. Once the wire disappeared into the wall and out of sight it was spliced into the existing knob and tube that the owner swore didn't exist. From appearances in the basement it was romex but only what you could see, the entire house was live knob and tube!

You buy those electrical testers at any hardware store for under $20. I'd say that would be a good start in investigating this further.
Image
Rebecca
1820's Urban Farmhouse in Eastern Ontario
(The picture is the "before" picture... before the PO's bought it and destroyed it. We're still trying to get it back to that.)
HouseNut
 
Posts: 414
Joined: Mon Apr 06, 2009 6:00 pm
Location: Ontario

Re: Old knob and tube tied into romex (is it live?)

Postby prairiebox » Fri Apr 10, 2009 1:13 pm

I just did an Amazon search for "live wire tester" and came up with a non-contact voltage detector that you just hold near a wire to test if its live. I never even knew such a thing existed :lol: Obviously electrical is NOT my thing. Scares the crap outta me. You can bet we're gonna be picking one of those up.
Image Visit my American Foursquare at http://prairiebox.blogspot.com
prairiebox
 
Posts: 337
Joined: Wed Aug 17, 2005 2:01 pm
Location: South Bend, IN

Re: Old knob and tube tied into romex (is it live?)

Postby brian89gp » Fri Apr 10, 2009 6:22 pm

My house has updated wiring supposedly, it is updated from the breaker panel to where it splices into the old knob and tube as soon as it goes into a wall.... Chances are your "updated" wiring probably isn't as updated as you think.

They have those live wire testers in just about any home improvement stores, they even have lineman pliers with a wire tester built in.
I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do.
-Heinlein
brian89gp
 
Posts: 267
Joined: Sun Aug 10, 2008 10:04 pm
Location: Kansas City

Re: Old knob and tube tied into romex (is it live?)

Postby bofusmosby » Fri Apr 10, 2009 6:57 pm

Yup, my house is the sme way. Its kinda half and half. The old knob and tube wiring I have is still in good shape, but the only thing I am running on this wire are small wattage lighting. This old type of wiring held up pretty good over the years, however, with the knob and tube, you have no ground, and it is not able to handle the currect that a lot of our appliances draw today. As stated before.....Be careful.....
Jim

Well, there goes the neighborhood!
bofusmosby
 
Posts: 333
Joined: Fri Dec 05, 2008 3:50 pm
Location: Tampa Florida

Re: Old knob and tube tied into romex (is it live?)

Postby Venn Diagram » Fri Apr 10, 2009 7:00 pm

Oh, boy, do I know how you are feeling. We also bought a "completely updated" house - had it inspected - had no idea whatsoever that everything between the first and third floors was tied into live knob and tube until a bathroom project revealed the frightening truth.

Who knows where that goes? No way to find out without following it and opening up the wall/floor, I guess. That is what we are going to do this summer.

Those disclosures that you have to sign in certain states? One year statute of limitations in IL. We discovered K&T a couple months too late. Otherwise I would have been drafting a nice firm demand letter to the previous owners, who knew exactly what they were getting away with.

Good luck! Safety first, always.

VD
Venn Diagram
 
Posts: 124
Joined: Thu Aug 24, 2006 11:23 am
Location: Chicagoland

Re: Old knob and tube tied into romex (is it live?)

Postby moonshadow317 » Fri Apr 10, 2009 7:24 pm

Those disclosures are meaningless in NY. We were told the roof was new, bought the house in June back of roof leaked like a sieve in Sept. called lawyer and was told they weren't legal documents that would hold up in court :evil: That wiring looks pretty live to me. It probably goes up into a light fixture in the ceiling of a room somewhere. The connection to the old should at least be contained in an accessable metal box (think light switch box with a closed cover) and then just leave it alone. K&T is pretty safe as long as it's left alone.
Karen
Image
moonshadow317
 
Posts: 1781
Joined: Fri Dec 19, 2003 5:03 pm
Location: Upstate & Queens, NY

Re: Old knob and tube tied into romex (is it live?)

Postby Matt in KC » Fri Apr 10, 2009 10:22 pm

I have about 10 of these connections in my house - that I can see.

We got a live wire tester at Lowe's for abour $20. It's green and works really well. I'm telling you this because I bought a second tester when I temporarily misplaced that one and it's junk. That one's yellow. Anyway:

The first thing you should do after you get the live wire tester is flip switches at the panel and see what's on that circuit. Then see if you can trace where that wire goes up through the house. And don't assume the K&T is pushing current to the Romex - it could be coming from the other direction.

Be careful with the live wire tester and the K&T because only one of those wires is going to show up as hot. The other one is the neutral. Make sure you check both and the Romex before drawing any conclusions about what is hot and what isn't.

What probably happened is they replaced all the K&T they could reach, and instead of ripping up that lovely plaster wall, they clipped the K&T at the attic and spliced the Romex in. If it's under insulation, you should go up and make sure the connection is in a metal junction box. My bet is it isn't. By code you need to add the j-box, but at the very, very least put new wire nuts on the ends and tape those on with electrical tape.
Matt in KC
 
Posts: 213
Joined: Wed Jan 02, 2008 2:47 pm
Location: Kansas City

Re: Old knob and tube tied into romex (is it live?)

Postby asiedydd » Fri Apr 10, 2009 10:59 pm

K&T is pretty safe as long as it's left alone.
More often than not, it hasn't been "left alone". http://www.oldhouseweb.com/how-to-advic ... ring.shtml
Check your homeowner's insurance policy and read the fine print exclusions.

Cheap voltage sniffers frequently produce false positives and sometimes false negatives. They shouldn't be used as a guarantee of life safety. You need to use a good multi meter to be sure.
asiedydd
 
Posts: 349
Joined: Sat Feb 04, 2006 12:40 am
Location: Southeastern PA & Central NJ

Re: Old knob and tube tied into romex (is it live?)

Postby bofusmosby » Fri Apr 10, 2009 11:29 pm

Thank you for the link. True, that knob and tube wiring is not recommended, and when ever possible, it should be replaced. However, I did read a mistake in the article. Quote "Switches were often placed on the neutral wire, turning off the circuit, but not the current". This is an incorrect statement. No matter where the switch is located, if the circuit is opened, then there is NO current flow. It should have stated that there would still be VOLTAGE present. Not current.

I think that all agree that with the old knob and tube wiring, if it can be replaced, it should be. However, I have a number of sconces on my original plaster walls, that draw very little current. If I were to replace all this knob and tube wiring inside the walls, then a large amount of the original plaster would also have to be destroyed. This is something I would really not want to do.
Attachments
100_0760.jpg
100_0760.jpg (71.48 KiB) Viewed 2360 times
Jim

Well, there goes the neighborhood!
bofusmosby
 
Posts: 333
Joined: Fri Dec 05, 2008 3:50 pm
Location: Tampa Florida

Next

Return to General Discussions Forum

Who is online

Users browsing this forum: Yahoo [Bot] and 7 guests