Knob & Tube into panel

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MJGero

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I did not pass a panel change due to all the knob and tube conductors just passing through a 2 inch pvc bushing into the panel. I cited 314.17(B) "Except as provided in 300.15(C) the wiring shall be firmly secured to the box or conduit body." He wants to take this to adjudication stating he has done it this way before and passed. Am I looking at this the right way?
 

infinity

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Sounds like insulated bushings are permitted:

312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures.
Conductors entering enclosures within the scope of this article shall be protected from abrasion and shall comply with 312.5(A) through (C).
(A) Openings to Be Closed. Openings through which conductors enter shall be adequately closed.
(B) Metal Cabinets, Cutout Boxes, and Meter Socket Enclosures. Where metal enclosures within the scope of this article are installed with messenger-supported wiring, open wiring on insulators, or concealed knob-and-tube wiring, conductors shall enter through insulating bushings or, in dry locations, through flexible tubing extending from the last insulating support and firmly secured to the enclosure.
 

MJGero

Member
Sounds like insulated bushings are permitted:

312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures.
Conductors entering enclosures within the scope of this article shall be protected from abrasion and shall comply with 312.5(A) through (C).
(A) Openings to Be Closed. Openings through which conductors enter shall be adequately closed.
(B) Metal Cabinets, Cutout Boxes, and Meter Socket Enclosures. Where metal enclosures within the scope of this article are installed with messenger-supported wiring, open wiring on insulators, or concealed knob-and-tube wiring, conductors shall enter through insulating bushings or, in dry locations, through flexible tubing extending from the last insulating support and firmly secured to the enclosure.
What about this part? The conductors are not "Firmly secured to the enclosure"
 

infinity

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312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures.
Conductors entering enclosures within the scope of this article shall be protected from abrasion and shall comply with 312.5(A) through (C).
(A) Openings to Be Closed. Openings through which conductors enter shall be adequately closed.
(B) Metal Cabinets, Cutout Boxes, and Meter Socket Enclosures. Where metal enclosures within the scope of this article are installed with messenger-supported wiring, open wiring on insulators, or concealed knob-and-tube wiring, conductors shall enter through insulating bushings or, in dry locations, through flexible tubing extending from the last insulating support and firmly secured to the enclosure.
What about this part? The conductors are not "Firmly secured to the enclosure"


You're reading that section incorrectly.

or concealed knob-and-tube wiring, conductors shall enter through insulating bushings

The requirement for K & T ends here.



or, in dry locations, through flexible tubing extending from the last insulating support and firmly secured to the enclosure.

This part refers to the flexible tubing being firmly secured to the enclosure.
 

MJGero

Member
isn't the "flexible tubing" the Loom? So you are saying that the "conductor" passes through an "insulated busing or flexible tubing" and that the "flexible tubing" needs to be "firmly secured to the enclosure"?
 

e57

Senior Member
No. That is part of the conductor insulation on K&T.
I'm going to have to disagree here. Flexible tubing - is just that - i.e. Loom. (Or for some - a sleeve of NM jacket. :rolleyes:) Conductor insulation is well - conductor insulation. The loom goes over each from the last Knob, and is secured to the enclosure. It's a raceway, and a required one. One per conductor.

Back to the OP though - this could have been solved in seconds right there with a zip tie.
gc-ct11bs.jpg
 

infinity

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Location
New Jersey
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Whether or not flexible tubing is the loom or not isn't really relevant to the question the OP. He said he violated a job where they ran the K & T conductors through an insulated bushing. According to 312.5(B) this is a permitted wiring method for knob and tube.
 

MJGero

Member
all the K & T conductors, lets say 12, 6 circuits, are in looms, and are all gathered and pass through the bushing (PVC 2inch conduit conector). none of the looms are "firmly secured to the enclosure". I don't see that passing through is firmly secured.

how would a zip tie solved this problem?
 

infinity

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Location
New Jersey
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all the K & T conductors, lets say 12, 6 circuits, are in looms, and are all gathered and pass through the bushing (PVC 2inch conduit conector). none of the looms are "firmly secured to the enclosure". I don't see that passing through is firmly secured.

how would a zip tie solved this problem?

The way I read 312.5(B) it permits the conductors to enter through the insulated bushing without the tubing, but if the conductors pass through the tubing then the tube needs to be secured. Initially you didn't specify that where passing through the bushing you also had the tubing around the conductors.
 

MJGero

Member
I was using the wrong term. The looms need to be firmly secured to the enclosure. Would you say individually or in pairs?
 

Hendrix

Senior Member
Location
New England
all the K & T conductors, lets say 12, 6 circuits, are in looms, and are all gathered and pass through the bushing (PVC 2inch conduit conector). none of the looms are "firmly secured to the enclosure". I don't see that passing through is firmly secured.

how would a zip tie solved this problem?
I think that the only way to make this compliant is for each loom to enter a 1/2" KO through its own connector.
 

infinity

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Location
New Jersey
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Journeyman Electrician
I was using the wrong term. The looms need to be firmly secured to the enclosure. Would you say individually or in pairs?


Since the enclosure is metallic I would say the two conductors of the same circuit through one KO with a connector but I wonder if there actually a connector listed for terminating loom?
 

brantmacga

Señor Member
Location
Georgia
Occupation
Former Child
I'm going to have to disagree here. Flexible tubing - is just that - i.e. Loom.


I don't completely disagree with you; but I would think the loom can be considered equal to a romex jacket.



Even if that's not the case, the electrician could install it inside another flexible tubing and be fine.
 

infinity

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Location
New Jersey
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The term flexible nonmetallic tubing is part of the NEC definition of knob and tube wiring. IMO that would apply to the old black flexible tubing designed for and used with K & T wiring.

394.2. Definition.
Concealed Knob-and-Tube Wiring. A wiring method using knobs, tubes, and flexible nonmetallic tubing for the protection and support of single insulated conductors.
 

hershey

Member
Location
hebron, ohio
In this area, most inspectors will give you grief running k&t into a panel. They perfer to see us terminate k&t into a nm junction box and run romex into the panel. This also give a professional finished look. I know this doesn't really address the if your inspector was correct but it might help the next time.
 

e57

Senior Member
The way I read 312.5(B) it permits the conductors to enter through the insulated bushing without the tubing, but if the conductors pass through the tubing then the tube needs to be secured. Initially you didn't specify that where passing through the bushing you also had the tubing around the conductors.
Well it's not allowed in the wall, or exposed without the loom or tubing - so choose a different violation....

I'm not a fan of the 2" bushing and dropping a dozen or so cables through it - 'cause it doesn't fly here - but I would be weary of K&T doing the same - even with loom. But if 'secured' is what you need, a zip-tie with a hole for a screw would seem like an easy fix to secure the loom bundle in the enclosure with a simple screw.

Most of the refeeding of K&T that I do, I'll put in a few 4 11's on the cieling and pipe back down to the panel - or put in a gutter above, and nipple into the panel. This is only because it keeps the panel neat. i.e. No tagged on conductors due to short lengths, or crappy 100 year old insulation to flake in the panel.
 
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