Knob and tube 600V

Status
Not open for further replies.
JJWalecka

JJWalecka

Senior Member
Location
New England
I was told recently that 600 volts used to be installed as Knob and tube! Does anyone have pics or info? I am a history buff and I am intrigued.

Thank you

JJ
 
chevyx92 said:
I disagree. If it's such a "Safe" wiring method then why isn't it used anymore???
Click to expand...

For one, cost. It would be much more costly to wire a home with K&T in place of NM, the labor would be much more.

To this day the NEC allows the installation of K&T, see Article 394.

One of the reason is that it is safer (assuming it is done correctly) is the porcelain fittings that space the conductors away from combustibles.

Also the fact the conductors are not contained in the same overall jacket greatly reduces the chance of a short circuit.

Anytime I have seen in person or in photos K&T that started a fire it was at the points where some unqualified person tapped into it incorrectly with more modern methods.

Let me spin it around.

What part of correctly installed, and over current protected K&T circuit worries you?
 
480sparky said:
Insulation (thermal, that is) is also a factor.
Click to expand...
As in 394.12 (5)? Uses not permited. So what happens when someone with K&T has their exterior walls insulated with blown in? I would assume that is a code violation....so why do insulation companies do it?
 
iwire said:
Why do electricians penetrate firewalls without sealing the hole up?
Click to expand...

I'm much more aware of that than what I used to be, say, 10 years ago.

I agree that K&T that has not been tampered with, is a very safe wiring method.
 
Chris6245 said:
....so why do insulation companies do it?
Click to expand...

Why should an insulation outfit care about wiring? I doubt they're going to 1.) investigate where any K&T might be and 2.) tell the HO they can't have insulation in those cavities. They get paid to install insulation, not read, comprehend and comply with that silly book called the NEC.:wink:
 
480sparky said:
Why should an insulation outfit care about wiring? I doubt they're going to 1.) investigate where any K&T might be and 2.) tell the HO they can't have insulation in those cavities. They get paid to install insulation, not read, comprehend and comply with that silly book called the NEC.:wink:
Click to expand...
I agree that it's not their job to know the NEC., but they should know their job and what's right and wrong...But what about inspectors that don't say anything when it is being blown in when they are doing an inspection on the removal of K&T in a basement when they know the K&T in the walls was not replaced. I have asked 3 inspectors in my area and I get the "Why would that matter" answer. I have K&T in my house (walls only) and wouldn't even think about insulating. I like to sleep at night knowing that there is nothing in contact with the wires. One day I'll remove the lath and plaster room by room and rewire so I can insulate the walls.
 
I have an old book on installing K & T. This book says to contact the electric company to see what type of electricity they provide!

Says some electric companies provide direct current and others provide alternating current. Refers to voltage in some places as "pressure".

For direct current, says usually 110 to 260 volts and sometimes 250 to 500 volts, but more than 250 seldom used for for buildings other than factories.

For alternating current, says electricity is provided in singlephase or polyphase and several voltages and frequencies. Says to ask electric company what they have before doing your wiring...
 
The book is one volume of a set and the specific book is called:
"International Library of Technology" - "Distribution of Electrical Energy".
Published by International Textbook Co. (1926)

For the above, I was looking at the "Interior Wiring" section of this book. The back of this section also includes "alarm wiring" and starts off with a picture of a "glass" battery.

Then it also has "sign wiring" including gizmos to make lights flash around a sign. The front of the book is on local and long distance transmission of electricity.

Copies of this old book can be found for sale at the following book
search site (Searches many different stores world wide)...
http://used.addall.com

For title enter: international library of technology
For keyword enter: distribution
Then click on Find the Book

Scroll down until you find a listing which says "Distribution of Electrical Energy".
 
P.S. Other books I have from this set are...

-Electric Measurements Lamps and Heating
-Electric Power Stations Testing and Operation
-Electric Railway Engineering
 
480sparky said:
Why should an insulation outfit care about wiring? I doubt they're going to 1.) investigate where any K&T might be and 2.) tell the HO they can't have insulation in those cavities. They get paid to install insulation, not read, comprehend and comply with that silly book called the NEC.:wink:
Click to expand...

They might care if they get sued for damages.They could cause a fire.
K and T was a great system.Problem is the house could not be insulated and far more costly in labor.
 
iwire said:
What part of correctly installed, and over current protected K&T circuit worries you?
Click to expand...
The fact that there is no ground conductor. And the insulation over time along with temp change disintegrates. That and "All" of the K+T I've ever worked on, I found they always seemed to switch the neutrals and not the hots.
 
Status
Not open for further replies.
Top