ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
MRI LED lights dimmer control replacement - wow!
by ghost307. 01/19/18 11:37 AM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
VDE 0100 to introduce AFCIs
by LongRunner. 01/17/18 10:32 AM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
1 registered members (Troy), 20 guests, and 11 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
More Knob and Tube #151549
03/06/03 08:44 PM
03/06/03 08:44 PM
Admin  Online Content
OP
Administrator
Member
Joined: Oct 2000
Posts: 3,481
NY, USA
[Linked Image]
Anatomy of a K&T conductor. Cloth over rubber over (tinned??) copper

[Linked Image]

Closeup of a K&T splice

[Linked Image]

Knob-and_tube wiring--notice the gas pipe from a gas light (ceiling shot)

[Linked Image]

This was behind a bathroom wall.

-ThinkGood

Tools for Electricians:
Re: More Knob and Tube #151550
03/07/03 08:02 AM
03/07/03 08:02 AM
T
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,409
Vienna, Austria
The wires look exactly like Austrian phone wire like it was used in the 1930ies and earlier, only the conductors were twisted around each other (3 wires). They also had the colored stripe.
I've often seen gas pipes in ceilings, most of them still connected to the supply. In many cases there would be a stopple with a hook in it, to hang the light fixture. In most cases solid enough to hang an elephant.
Expert splice, and without doubt perfectly accesible! [Linked Image]
Power wires usually looked the same but the cloth was impregnated with a bituminous compund. Makes for absolutely black fingers when working with that stuff!

Re: More Knob and Tube #151551
03/07/03 08:06 PM
03/07/03 08:06 PM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,264
Fullerton, CA USA
I've come across some old K&T that's been in pristine condition. Sometimes it makes me kinda sad to tear out the old stuff and put in new plastic parts. It used to be a heck of a lot of work to drill with a brace and bit. You've got to appreciate their attitudes when nowadays guys don't even carry screwdrivers, but just a couple of different bits for their cordless drill.
(Check out the "labor intensive" lath in the wall with the flying splice)

Re: More Knob and Tube #151552
03/10/03 12:12 AM
03/10/03 12:12 AM
S
SvenNYC  Offline
Member
Joined: Aug 2002
Posts: 1,691
New York City
I know the "knobs" are still sold...but usually it's now used for attaching antenna wire to a building....or things like electric "bird repellers."

A mail order supply house that caters to the old-radio repair hobby carries them (http://www.tubesandmore.com).

What about the ceramic tubes, are they still manufactured?

I wonder if an electric supply house counterman would look at me weird if I went in and asked for knobs and tubes....of course I guess nowadays you'd have to use THHN/THWN wire instead of that cloth & rubber coated stuff, so it would DEFINITELY be breaking a whole lotta codes in the book! [Linked Image]

Re: More Knob and Tube #151553
03/10/03 01:18 PM
03/10/03 01:18 PM
K
kale  Offline
Member
Joined: Nov 2002
Posts: 174
Sven
Porcelain Products shows standard porcelain tubes and 5 different kinds of knobs in their catalog. Unfortunately, their website http://www.ppcinsulators.com does not show their products.

Re: More Knob and Tube #151554
03/10/03 09:31 PM
03/10/03 09:31 PM
S
stamcon  Offline
Member
Joined: Mar 2001
Posts: 330
So San Francisco CA
K&T is still allowed for extensions on existing installations or elsewhere with special permission. Article 324


Steve
Re: More Knob and Tube #151555
03/16/03 09:46 AM
03/16/03 09:46 AM
L
ldwilson  Offline
Junior Member
Joined: Mar 2003
Posts: 4
Seneca,SC,USA
As professional electricians what are your feelings about leaving K&T in place in older homes.
As a licensed home inspector I have seen some really scary K&T in place and always recommend that one of you evaluate the wiring for replacement.
As I understand, most K&T applications are okay as long as the sheathing isn't breached. But I have never seen a home with K&T that some amature hadn't made at least some modifications to add ceiling fans, bathroom vent fans, etc.
Thanks for the input.
Larry W.
South Carolina


Larry W.
Re: More Knob and Tube #151556
03/16/03 08:56 PM
03/16/03 08:56 PM
T
ThinkGood  Offline
Member
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
Larry:

I'm not an electrician, but I can tell you that the electrician who was hired to rewire the house in the photos said he is going to disconnect all of the K&T, as it is at least 70 years old.
- - - -

Something else I just noticed, third photo down...Where there is a tube that sits on top of another tube (perpendicular to it), small coils of wire were placed on either end of the tube to keep it from sliding. I saw this in similar situations throughout the house. Seems that nothing went to waste back then...

Regarding the last photo shown, no box was used to enclose the splice, and the Romex is not supported properly.


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
dougwells
dougwells
kamloops BC Canada
Posts: 1,142
Joined: May 2003
Show All Member Profiles 
Top Posters(30 Days)
Admin 20
sparky 18
Potseal 14
Popular Topics(Views)
243,552 Are you busy
180,359 Re: Forum
170,837 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.022s Queries: 14 (0.003s) Memory: 0.9939 MB (Peak: 1.1535 MB) Zlib enabled. Server Time: 2018-01-19 19:23:19 UTC