Subscriber Discussion

Per Code, Does Low Voltage Require Bushings While Going Through Metal Studs?

UI
Undisclosed Integrator #1
Mar 21, 2017

Per code does low voltage (data wires, IP cameras, etc...) require bushings while going through metal studs?

 

Thank you

UI
Undisclosed Integrator #2
Mar 21, 2017

I know this doesn't answer you question but I find necessary just for the simple reason that it mostly eliminates issues with shorts caused by the wire sheathing being stripped back during the roughing phase.

 

Any they are so cheap, I can't see a business reason not to use them. 

 

I hope I enlightened you.

UI
Undisclosed Integrator #1
Mar 21, 2017

I agree that there is no reason why not to install them. However we are dealing with a "after" situation. Basically work was done (not by us) without bushings and the inspector is giving the client headaches. 

In order to fix it, we would need to cut open roughly about 100 pieces of sheetrock.

 

Thank you

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U
Undisclosed #3
Mar 21, 2017

So, I will also not help you, other than to say that if the inspector has a problem with it, it doesn't really matter what code says. The unfortunate reality of dealing with an AHJ is that they are effectively "god" (especially in their own minds) and can do whatever the heck they want.

I would definitely want some documentation as to exactly what he wants and how he proposed that it be rectified if he does force you to replace it. 

I can also tell you that, during construction, we specify, at minimum, 1/2" flex through any metal walls for the reason in the first response. Required? Probably not. Best practice? Absolutely.

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Ari Erenthal
Mar 21, 2017

I believe it's NFPA 70 300.4(B)(1).

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Mark Jones
Mar 21, 2017

Yes. 

You need to use some sort of bushing when wiring with Romex to comply with paragraph 300.4(B)(1) of the NEC, which states that: "in both exposed and concealed locations where nonmetallic-sheathed cables pass through either factory or field punched, cut, or drilled slots or holes in metal members, the cable shall be protected by bushings or grommets covering all metal edges and securely fastened in the opening prior to installation of the cable." Not all bushings will work with all types of holes in the metal studs.

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Brian Rhodes
Mar 21, 2017
IPVMU Certified

I agree with you, but the OP specifically was asking about 'low voltage' (not romex) cable.

I do not believe the provisos of high voltage code apply in this case, but whatever the AHJ says is what needs to be followed.

UI
Undisclosed Integrator #1
Mar 22, 2017

Long story short, a LV contractor left a job and we were asked to finished up.

Roughing was complete already. Inspector came, saw that going through the metal studs into the open walls there were no bushings. He wants them added. No big deal. However, he also wants the contractor to open up the already sheetrocked ceiling to verify that there are bushings were ever needed. 

 

The contractor says that in the ceiling the wires were never pulled through any holes. And is willing to show pictures. The inspector says the pictures are not good enough, he wants it opened (5k sqft building). If we can show that really it isnt required according to code, then maybe the inspector will accept pictures instead (hopefully)

JH
Jay Hobdy
Mar 22, 2017
IPVMU Certified

That section does not specify a voltage so I would have to say it needs bushings. Unless you can find an exception....

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Mark Jones
Mar 22, 2017

My response what poorly worded.  My apologies.  The voltage would not matter.  In the code reference above, his answer is "the cable shall"....The code does not mention a voltage, hence it applies to all voltages.  

There is a misnomer that the AHJ can just make it up.  That is not entirely accurate.  They do have final say, but their interpretations have to be based, liberally or conservatively, in the code.  You as a licensed installer have the absolute right to challenge their ruling.  Their opinions should be based on the code.  That is why in today's working environment, license holders and inspectors all attend the same Code classes.  Obviously, if you do that, you are not going to make any friends at the local code enforcement office, but what do you have to lose?  It sounds like he is going to make the customer's life uncomfortable anyway.  

I would ask if this job had a permit?  If so, it was likely that the wiring was to be inspected before the ceiling was closed.  It is generally incumbent upon the contractor that holds the permit and commonplace to get that "rough-in" inspection.  If not, you suffer consequences.  It sounds like your inspector is a stickler.  The owner will probably have to pay the price for the previous contractor's negligence and if I were the owner, I would go back to that contractor for my money.  

As I read all of this, the inspector does not really have an issue with your work.  He wants to see the work of the previous installer, and he does have that responsibility.  On a very recent job of ours the inspector came in to inspect our work.  We had installed the wiring in an existing hard ceiling.  The inspector showed up, used the same ceiling access we used for our work, jumped right up the ladder and got right up in there and inspected everything, grommets and all, without hesitation.  He did not ask for the sheetrock to be removed.  That would place an undue burden on the owner.   He was nice, professional and reasonable.  Frankly, it sounds like your inspector is not.  He/she sounds lazy to me, even though it sounds like the previous contractor did not call in their rough-in inspection.  Everyone has to deal with what is, today.  

Over the years I have seen instances like this before; a sprinkler test not performed before the carpet/flooring was installed, wiring covered up before the inspector reviewed the work, etc.  It is up to the inspector as to what he/she will/will not accept.  They tend to error on the side of caution.  Good luck!

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CH
Corbin Hambrick
Mar 28, 2017

However, doesn't the NEC have a minimum voltage the code addresses?

I don't think NEC code would apply hear.  Of course that may not matter if local authorities have their own additional requirements.

JH
Jay Hobdy
Mar 28, 2017
IPVMU Certified

No. The NEC applies to all electrical and data wiring.

The NEC has very broad sections like chapter 300 that state how all wiring shall be performed. Then there are sections like chapter 700 and 800 that address specific areas of low voltage. If you can find something in there that states otherwise, then that would apply. But it doesnt so chapter 300 applies. 

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