# Running cables behind finished walls - Code clarification



## PokeySmokey (Nov 14, 2017)

Why are you quoting NEC 334.30?

Manitoba goes by:

What is the electrical code for Manitoba?
Canadian Electrical Code, Part I, 24th edition, CSA Standard C22.1-18, is incorporated by reference as part of this regulation and is adopted as the electrical code for Manitoba.

I would never install BX that way. it is harder but you can still drive a nail through the BX covering.


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## Navyguy (Mar 15, 2010)

NMD can be fished, no need for BX. I think I would be more concerned about connecting other people's wiring and devices. If the wiring was installed before drywall, then I think you are missing an inspection or two and the cable still needs to be 11/4" from the face of the stud and attached to the stud properly.

RUN, RUN, RUN!

Cheers
John


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## wcord (Jan 23, 2011)

I'm assuming the customer fished the cables from the ceiling, down the walls to the heaters?
I'll guarantee you, he neglected to tell Hydro HOW he fished the cables. Even with AC90, the poly will hold the cables tight to the drywall, and as mentioned, could be damaged by picture hangers or some such nail.
I would suggest fishing the cables behind the insulation. Hard but not impossible


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## treznik (Nov 12, 2017)

PokeySmokey said:


> Why are you quoting NEC 334.30?
> 
> Manitoba goes by:
> 
> ...


When I can't find what I'm looking for under the CEC I look to the NEC code for potential guidance. Occasionally the wording gives me a hint of how to search the CEC to find comparable code. Because I found that the NEC seems to cover running wires behind finished walls I tried to look back to the CEC but could not find comparable code.


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## treznik (Nov 12, 2017)

Navyguy said:


> NMD can be fished, no need for BX. I think I would be more concerned about connecting other people's wiring and devices. If the wiring was installed before drywall, then I think you are missing an inspection or two and the cable still needs to be 11/4" from the face of the stud and attached to the stud properly.
> 
> RUN, RUN, RUN!
> 
> ...


Wiring was installed after finished drywall. Customer found basement heat vents insufficient since heat is regulated by main floor thermo. He ran the romex above the drop ceiling stapled to joists and cut hole in wall above the ceiling support to run wire between insulation and drywall. He cut another hole at the bottom of the wall where heater is mounted and fished the romex through it. I discovered this by reviewing his work and questioned his self wire permit.
I don't want to do this job unless I find the appropriate guidance/code. Even though I proposed replacing Romex with AC90 customer is aware I am reviewing code.


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## treznik (Nov 12, 2017)

wcord said:


> I'm assuming the customer fished the cables from the ceiling, down the walls to the heaters?
> I'll guarantee you, he neglected to tell Hydro HOW he fished the cables. Even with AC90, the poly will hold the cables tight to the drywall, and as mentioned, could be damaged by picture hangers or some such nail.
> I would suggest fishing the cables behind the insulation. Hard but not impossible


I agree going behind the insulation would have been better. I'm too old for that job!! Can you point me to the code though? Section 12 doesn't seem to contemplate this.


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## canbug (Dec 31, 2015)

Fishing a wire through a finished wall does not need to be fastened. It's not the best but I don't think it breaks any rules. 
If he drives a nail trough it, it will need to be repaired, if he hangs a shelf with some 4 inch screws, he could also hit any wiring in the stud?
If you don't want to do this job, just let him find someone else.

Tim


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## r0yal (Apr 12, 2020)

12-510 (3)
Notwithstanding Subrules 1) and 2), where the cable is run as concealed wiring such that it is impracticable to support it, and where metal sheeting or cladding, metal joists, metal top or bottom plates, or metal studs are not used, the cable shall be permitted to be fished and need not be supported between boxes and fittings.

The protection against mechanical damage is for exposed wiring. Needing to be 1.5m


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## joe-nwt (Mar 28, 2019)

A picture nail would just push the cable out of the way.


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## joe-nwt (Mar 28, 2019)

treznik said:


> When I can't find what I'm looking for under the CEC I look to the NEC code for potential guidance. Occasionally the wording gives me a hint of how to search the CEC to find comparable code. Because I found that the NEC seems to cover running wires behind finished walls I tried to look back to the CEC but could not find comparable code.


Amazing how convoluted the code has become. Why is there an Appendix B? Why can't they just put that Appendix B information in with the applicable code. Same with most of the tables. Why do you have to flip back and forth a half dozen times to get all the info you are looking for?

Rant off.


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## 99cents (Aug 20, 2012)

joe-nwt said:


> Amazing how convoluted the code has become. Why is there an Appendix B? Why can't they just put that Appendix B information in with the applicable code. Same with most of the tables. Why do you have to flip back and forth a half dozen times to get all the info you are looking for?
> 
> Rant off.


It’s so apprentices can waste valuable time writing exams because they missed “See Appendix B”.


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## treznik (Nov 12, 2017)

So customer called me back and I indicated he should rerun wires behind the insulation instead of AC90. He was happy about that suggestion and will redo the wiring. Thanks to wcord for the suggestion. Nice to keep a good customer happy and well advised.


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## PokeySmokey (Nov 14, 2017)

treznik said:


> When I can't find what I'm looking for under the CEC I look to the NEC code for potential guidance. Occasionally the wording gives me a hint of how to search the CEC to find comparable code. Because I found that the NEC seems to cover running wires behind finished walls I tried to look back to the CEC but could not find comparable code.


Read the following post by Navyguy which clarifies running cable through studs joists.



Navyguy said:


> NMD can be fished, no need for BX. I think I would be more concerned about connecting other people's wiring and devices. If the wiring was installed before drywall, then I think you are missing an inspection or two and the cable still needs to be 11/4" from the face of the stud and attached to the stud properly.
> 
> RUN, RUN, RUN!
> 
> ...


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## mofos be cray (Nov 14, 2016)

joe-nwt said:


> Amazing how convoluted the code has become. Why is there an Appendix B? Why can't they just put that Appendix B information in with the applicable code. Same with most of the tables. Why do you have to flip back and forth a half dozen times to get all the info you are looking for?
> 
> Rant off.


The cec is a legal document and it has the weight of law when adopted. The appendices are explanations or clarifications of the the law. No jurisdiction adopts the appendices into law but all jurisdictions adopt the codes, tables and diagrams. With the caveat that most jurisdictions modify some few parts of the code prior to adoption.


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