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.
Last edited by Niko; 10/19/1111:35 AM. Reason: added
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.
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.
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.