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#190990 - 12/14/09 05:14 PM old knob and toob wire
jimbob Offline
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Registered: 12/08/09
Posts: 15
Loc: Canada
in nova scotia it used to be code that if you couldnt remove all the old knob and toob when doing a rewire you could put that circuit on a gfci, usually by panel.could some tell me if this is still code.
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#190994 - 12/14/09 06:03 PM Re: old knob and toob wire [Re: jimbob]
HotLine1 Offline


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Registered: 04/03/02
Posts: 6776
Loc: Brick, NJ USA
Jimbob:
Welcome to the ECN forums! One of my neighbors up north of the border will jump in & give you an answer!

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#190999 - 12/14/09 08:40 PM Re: old knob and toob wire [Re: jimbob]
dougwells Offline


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Registered: 05/03/03
Posts: 1137
Loc: kamloops BC Canada
Originally Posted By jimbob
in nova scotia it used to be code that if you couldnt remove all the old knob and toob when doing a rewire you could put that circuit on a gfci, usually by panel.could some tell me if this is still code.

yes it is still code
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#191009 - 12/15/09 04:17 AM Re: old knob and toob wire [Re: dougwells]
jimbob Offline
Member
Registered: 12/08/09
Posts: 15
Loc: Canada
its nice to remove all the old wiring but you sometimes cant get it all. thanks for info.
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#191024 - 12/15/09 03:15 PM Re: old knob and toob wire [Re: jimbob]
mikesh Offline
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Registered: 06/07/06
Posts: 613
Loc: Victoria, BC, Canada
One word of caution about rewire and Knob and Tube. Yes it is Kosher and compliant to gfci protect the first outlet and put regular 3 wire receptacles on the circuit. I like to see the outlets downstream with lables indicating they are GFCI protected and don't have a bonding conductor.
The big problem with K&T is the temperature rating and newer luminaires. Many newer luminaires are to be connected to a wire with a 90 degree temperature rating. Trouble is K&T is only 60 degree insulation so a new fixture could destroy the insulation in short order.
New fixture also rewuire a bonding connection and some jurisdictions will allow the circuit to be gfci protected without adding the bonding wire. Check with your inspector.
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#191028 - 12/15/09 04:53 PM Re: old knob and toob wire [Re: mikesh]
sparky Offline
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Registered: 10/18/00
Posts: 5303
so would adding a few inches of newer 90C wire in the box bettween the K&T and fixture wire(s) make this compliant mikesh?

~S~
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#191031 - 12/15/09 07:26 PM Re: old knob and toob wire [Re: sparky]
frenchelectrican Offline
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Registered: 02/06/03
Posts: 939
Loc: Wi/ Paris France { France for ...
Originally Posted By sparky
so would adding a few inches of newer 90C wire in the box bettween the K&T and fixture wire(s) make this compliant mikesh?

~S~


For my answer is no it is not compliant at all due the oringal T&K do not have grounding conductor there at all and I did recall the NEC stated that you can not extend the groundless conductors.

Merci,Marc
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#191212 - 12/21/09 04:00 PM Re: old knob and toob wire [Re: sparky]
mikesh Offline
Member
Registered: 06/07/06
Posts: 613
Loc: Victoria, BC, Canada
For circuits originally supplied with a bonding wire IE nmd3 or MD about 450 mm of 90 loomex will look after the heat issue but the bonding cannot be done from a K&T circuit.
I don't mean 18 inches of wire in the box either. You need to add a jb. If you have attic space it is easy to relocate the old Jb in the rafter and put a new one with the higher temp wire in the place of the ceiling outlet.
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#191259 - 12/23/09 05:57 AM Re: old knob and toob wire [Re: mikesh]
sparky Offline
Member
Registered: 10/18/00
Posts: 5303
intersting, so would said JB be plastic, and the bonding wire taken out of the 90 loomex here (assuming a K&T circuit without one) ?

~S~
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#191430 - 12/28/09 11:58 PM Re: old knob and toob wire [Re: sparky]
Sixer Offline
Member
Registered: 08/08/05
Posts: 265
Loc: Canada
Originally Posted By mikesh
If you have attic space it is easy to relocate the old Jb in the rafter and put a new one with the higher temp wire in the place of the ceiling outlet.


If you have attic space then there should be no reason why the knob and tube can't be replaced.

Knob and tube wiring is 60+ years old, has no ground, and SHOULD be replaced, regardless of the condition. Everything has a lifespan, including wiring.

Just because the Code allows us to protect a K&T circuit with a ground fault protector or install a loomex jumper (or high temp sleeving) to make fixture boxes 90C compliant, in my opinion it should only be used as a temporary measure until replacement is done. I'll get down off my soapbox now smile
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