I have been on this board for a long time and I sometimes forget which topics we have discussed.

Anyway what is everyone's thought about using tie wraps to secure AC or MC cables to metal studs in a construction job? Should it be allowed? Is it allowed? Code sections or manufactures instructions?

as far as i know it is OK.

330.30 Securing and Supporting
(A) General. Type MC cable shall be supported and secured
by staples, cable ties, straps, hangers, or similar fittings
or other approved means designed and installed so as
not to damage the cable.

But i have had people say "approved means" is to be approved for that purpose but some say "approved means" basically means an approved strap or tie that has been approved for general strapping.

All though there are staples that are designed for romex and bx cable and romex cable only. I dont see any difference in them but they are listed for two separate cables.

Well, since that code citation specifically names cable ties and then goes on to say "or OTHER approved means" I'd say they were fine. I've never been turned down for it when I pointed this out to the AHJ.

The only admonition I have is that you have to be sure they are tied in a way that insures the 1.25". I see guys get pretty sloppy with tywraps, making the whole process look like an after thought. Remember the intent.

There is another problem, not really safety related but an issue for the building owner/tenant. If you do not strap metal wiring methods down well, it will rattle every time someone slams a door or a big truck goes down the road. I had a loose EMT in my wall at work that was really annoying. I finally poked a hole in the wall and fixed it when they were getting ready to paint the place. After listening to it for 2 years, I knew right where to look.

Ty wraps are acceptable for support. As Greg said, sometimes it tends to get sloppy, and the 1.25" non-compliance buys a red sticker.

On a similar note...any thoughts to using 'tape'? Electrical tape, black or any color??

Some guys try to get away with tape to the ceiling wires.

The only concern I would have would be where fire code for a commercial building would prevent using ordinary plastic ties and instead would require either the steel ties or the plenum/fire rated plastic ties.
Other than that, I don't really see a problem.

Nylon tywraps are going to melt at the same temperatures that will ruin the insulation of THHN.

So I've never had an AHJ object to them.

Indeed, super ty-wraps are routinely used by other trades ( HVAC ) for installations above the grid.

IMO, the fire code would be more about smoke control and keeping things secured when heat buildup occurs. The regular plastic ties will likely add more more toxic smoke to an area as well as melt long before the metal of the MC or armored cable does, which could release the bundles of cables and allow them to fall, creating even more property damage and additional hazards to first responders.

I believe these are usually just holding the wiring method in place until the rockers are done. After that the cables could be fished so we don't care if they fall down ... or so the logic goes.
If this was exposed work, I doubt I would let tywraps be used.

Plenum rated ty wraps solve the fire code aspects of smoke/toxic fumes, as do the stainless steel ty wraps. The ss are cheaper then the plenum rated, last I heard.

The last jib I saw the plenum rated, they were easily identified by 'purple' color. I don't know if that is a mfg 'standard', or was just for that particular brand.

The job was suppose to be a small commercial job with steel studs. The EC drilled 2 small holes in the stud, stuck a tie wrap through the holes and pulled it tight. It held the BX/MC close to the steel stud. He got a failed sticker. My thoughts to him was, Is the tie wraps Listed and labeled for the application? If so, then he should not fail the job. However if they were not listed the AHJ had every right to fail him.

Now comes the all important 90-4 section of the NEC. Should the AHJ fail him for that?

No, that is not a valid fail. 90.4 don't work. That siad, drilling the holes for the ty wrap sounds more labor intensive that using an MC/BX/AC one hole strap & zip screws!!! But, commonsense is not in the NEC either.

If the guy took the time to drill 2 holes I am not sure why he didn't just use a one hole strap and a tek screw but I would pass the tywrap.
The intent of keeping the cable away from the rockers was met.
"Cable tie" is one of the prescribed strapping methods as Niko pointed out.

The one I have problems with is when they just wrap it around the whole stud and sort of center the cable before they pull it tight.
I assume the rocker will cut it anyway so his rock will lay better. I have never had it on one of my jobs but I saw it in single family with Romex, my wife's job. Shortly after that they started using tywraps with the screw hole in them and a tek. I don't know if Lee County busted them or what.

I see this on resi basement jobs that are framed with 2x3 steel studs, perimeter walls. The tele data guys use ty wraps with the screw hole & tek screw.

John,

Again, common sense doesn't come into play here on either side of the job. My only reason for this whole question was that an EC complained to me that the AHJ failed him for using tie wraps. He wanted to know if he could fight this one. My first response was that if he could find something in the manufactures instructions, then I thought he could win. No instructions, then he might have to go by what the AHJ wants.

Greg,

I also have seen tie wraps with the 1 hole in it so that all you do is tek screw and tie tight. I think it is a quicker way to install. I used to use the metal BX 1 hole straps to mount BX also. That was another way to do it. I have also seen where EC's use every trick in the book to try and save every cent that they can on a job. Especially right now when the bidding is so tight. My old boss would make me drill 2 holes in a metal old work box, then cut it in next to a stud. This way he could save the use of 1 madison bar holder. (The metal strip which looks like an "F" that holds old work boxes in the sheet rock.)

Harold:

IF that 'fail' was taken to the Board of Appeals, the EC would previal based on 330.30 Period, done deal)

The real world situation is, how bad does the EC want to stand his ground? Unfortunatley, time is a precious commodity, and a delay of job for at least 30-60 days can be costly to say the least.

Plus, there are other repercussions that may occur!

Back in the happy days my wife says they had the cost of a house delay figured to average $350 a day, just in lost interest on the money. That is why they pushed so hard to keep things moving.

And there's the politics of fighting and winning.

AHJ's hate being overruled.

Our working philosophy is to just go with the flow. This has us doing some pretty crazy stuff sometimes.

We just can't afford to be right.

The most common method around these parts for MC in a metal stud wall is to secure it with a piece of doubled up tie wire (like the rod busters use), using the pre-punched holes in the stud.
Inexpensive, readily available, and quick.

I've never seen any inspector question it, much less cause a ruckus over its use.

John,


330.30 states that "MC cable shall be supported and secured by staples, cable ties, straps,hangers, or similar fittings..."

Like I said, the EC might have a hard time finding something from the manufacture that says it is listed and labeled for the application.

Also as Electure said, Most inspectors don't care their use.

Thomas and Betts invented the Tywrap and I looked on their site for the installation instructions but that document 404's
I have a question into the support desk.

I did find this in the FAQ



So I guess there are U/L listed tywraps but you would have to see the bag. If these are no name Chinese ties, who knows?

Harold:
The only thing I ever saw on a bag of Ty-Wraps (T&B) was something to the wording of flame/smoke spread, that was on a bag of 'purple' or 'maroon' T&Bs; that was at least 5-7 years ago at a car dealer new bldg.

Telco/data guy had them; EC went to pick up some at Cooper...till he found out the $$$; he came back with ss ty-wraps; no issues.

I looked over a bunch of the bags for Gardner Bender cable ties today at a box store and they all seem to be "recognized" (UR) but none showed a listing mark.

Still no answer from T&B

Now that you mentioned it, I never really noticed it before, but I have a couple of bags of the Band-It stainless ties that I know are UL listed, but they only say it on the instruction sheet that comes inside the bags. Nothing at all on the ties themselves. You’d think that if they went to all the trouble of getting them listed that they would slather it all over them. I guess if anyone ever calls me on it I will have to dig one of the bags out of the trash.

I also have a bag of those nylon standoffs that you put a screw in the middle and run the tie through the slots. Nothing marked on those either, so I guess you have to check that any accessories like that used with plenum rated ties are also rated.

i had thought i;'d read some manner of UL sanctioning for tie wrap's inclusion towards means of securement.....

~S~

Here is a link to a power point about the U/L listing standard for cable ties. I imagine we should be looking for a listing mark if we really want to follow the letter of the law.
http://www.nema.org/prod/be/cable-ties/upload/New%20UL%2062275.ppt

This is the NEMA article
http://www.nema.org/prod/be/cable-ties/

I am not sure you know whether the ties you see come from the "golden bag" the guy has been carrying in his truck for a year.

It seems to me that there can be a lot of fuss over very small items in the code.

Code aside .... IMO tywraps are 'temporary.' Even indoors, give them a few years and they become as brittle as glass.

Again, we're finding that one size does not fit all. What might be fine for hanging a few phone lines from the steel trusses above a drop ceiling might not be so smart when you're hanging a 12-pc bundle of #8-3 MC or 4" EMT.

It is fairly easy to argue that strapping cables in walls is just to keep them away from the rockers and serve little purpose after the rock is up. After all we can fish cables after the rock is up and the code is OK with that.
All ty-raps are mot created equal tho. I have some that seem to last forever and others that get brittle pretty fast. The problem is they all look the same. It should be noted that the T&B site said the U/V protected ties are not plenum rated. That might be important when you are using them in air handling spaces.

Reno:

"Code aside .... IMO tywraps are 'temporary.' Even indoors, give them a few years and they become as brittle as glass."

I cannot predict the future! Nor, could any other inspector.

"What might be fine for hanging a few phone lines from the steel trusses above a drop ceiling might not be so smart when you're hanging a 12-pc bundle of #8-3 MC or 4" EMT."

That I agree with you on. I have yet to see anyone try that!!