The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Calling all Non-US members!! (Non-US only)
by aussie240
Yesterday at 02:39 AM
Photo Upload Tutorial
by DanK
12/06/16 11:35 PM
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
0 registered (), 196 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#8977 - 04/10/02 06:29 PM Knob and Tube.. all got to go?
Electricmanscott Offline
Member

Registered: 01/12/02
Posts: 1478
Loc: Holden, MA USA
Going to check out a job next week. People are buying an old house which of course has knob and tube wiring in there. Their insurance company will not insure unless the wiring is replaced. This is the first time I have ever heard of this. Anyone else. House is in MA.

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#8978 - 04/10/02 07:10 PM Re: Knob and Tube.. all got to go?
spkjpr Offline
Member

Registered: 12/01/00
Posts: 226
Loc: Sedalia,MO, USA
I had never run across that but I personally try to persuade people to remove it. I guess it is ok as long as it's in good shape but it just wasn't ever expected to carry the loads of today. I won't use over a 15 amp if I can't remove it.

Top
#8979 - 04/11/02 05:22 AM Re: Knob and Tube.. all got to go?
frodo Offline
Member

Registered: 05/16/01
Posts: 129
Loc: louisville, ky usa
hi,
as far as i know it is not allowed to extend or modify any existing knob & tube wiring.

additionally most insurance companies will not insure a home with FUSES. i have never seen knob and tube with breakers!

how would you even attach to knob and tube anymore? all splices have to be in a box..right?

i always advise removing the stuff and i will never add to it or repair it. your asking for trouble if you do..

-regards

frodo

Top
#8980 - 04/11/02 07:56 AM Re: Knob and Tube.. all got to go?
ElectricAL Offline
Member

Registered: 10/10/01
Posts: 615
Loc: Minneapolis, MN USA
Electricmanscott

Unless there is a wiring mess in the house you are going to look at, I'd suggest the new owners consider getting quotes from other insurance companies. A lot of this confusion comes from loyalty to an Insurance Agent.

I work in Minneapolis / St. Paul and the seven county metro area. The core cities have late 1800 to 1925 housing stock. The original wiring is still in service and in most of the buildings is K&T. K&T's weakness, IMO, is the insulation. Where exposed in basements and attics, humidity and temp cycles degrade the insulation. Over fusing and subsequent overloading will warm the insulation enough, long enough to make it brittle. If it cracks when flexed, it's toast. As long as there is no history of overloading, the K&T in the interior walls has been very stable, in my experience.

I work a lot on old K&T systems and find that it is a sturdy stable (although limited) system that is standing up well under the test of time when not abused.

Splicing of modern wiring can occur at any outlet or light where the unswitched hot and neutral are present. Installing a box at the light may be necessary, as it may not yet have been done. (I've seen my share of modern luminaires supported by drywall screws shot to the lathe.)

Bottom line. . .to the home owners, even if the insurance of existing cared for K&T costs $xx.xx more a year in premiums, how many years of saved premium expense will it take to equal the cost of replacing the existing core wiring system of their new "old house"?

Al
_________________________
Al Hildenbrand

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals