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Posted By: Local Listed straps for MC? - 02/12/05 08:13 AM
I'm having some trouble finding exactly what straps are listed for use on MC cable. I'm putting together a crash course on installing MC for the new guys and I want to include as much good information as possible. Personally the only strap I ever find I need is a standard one hole MC strap. I'm not even sure where I should look to see if other methods are compliant. Many of the guys like to use zip-ties in some cases. Others like 3/8" drive straps. Can anyone point me to a resource that will help clear up my confusion? Mainly I'm looking to squash once and for all what is and what is not listed for strapping MC.

If anyone also has any other good info they'd like to share about MC I would love to hear it. I thought I would just throw together a quick presentation for the guys no problem. The more I write and the more I read, it becomes clear I need to give them the whole picture even if I don't already know the whole picture myself.
Posted By: iwire Re: Listed straps for MC? - 02/12/05 11:27 AM
Who says MC supports must be listed? [Linked Image]

You can use anything that the inspector will accept.

The majority of the jobs we work are MC and we do use some tie wraps.

This can be an issue above a ceiling that is used as 'other environmental air space.

Some inspectors say 300.22(C)(2) requires the tie wraps listed for use in environmental air space. (plenum rated) I personally do not see it that way.

For these inspectors we use bailing wire.

2002 NEC
Quote
300.22(C)(2) Equipment. Electrical equipment with a metal enclosure, or with a nonmetallic enclosure listed for the use and having adequate fire-resistant and low-smoke-producing characteristics, and associated wiring material suitable for the ambient temperature shall be permitted to be installed in such other space unless prohibited elsewhere in this Code.

As a tie wrap is not an 'enclosure' IMO it does apply except for the ambient temperature part.

You can also find a bunch of different types of supports from Caddy or B-Line.
Posted By: Roger Re: Listed straps for MC? - 02/12/05 12:46 PM
As Iwire says, you can use just about anything the local inspector will approve. We use rings or hooks for home runs and will group a few cables together to keep from supporting each individual cable.

After that, for single runs, we will use tie wire or cable ties inside concealed areas, and 3/8" straps or even strut and straps for entering panels or where it is desired to have a little better appearance.

The installation can still be neat and orderly.

Roger



[This message has been edited by Roger (edited 02-12-2005).]
Posted By: Local Re: Listed straps for MC? - 02/12/05 03:58 PM
It would appear so. I suppose I always assumed that only certain straps would be acceptable. Between one-holes and caddy I'm personally set so I guess I've never known what other materials our inspectors will pass. I think I'll get a bit of info from friends working for other contractors and see what strapping methods we come up with. Good, now I can move past strapping and start the next bit.

Thanks for the info
Posted By: dmattox Re: Listed straps for MC? - 02/12/05 04:09 PM
We use bailing wire, 3/8" one hole straps and Caddy KX clips. Never used anything else.

I've heard people question straps on their UL listing which I find funny. If your going to go that far, shouldn't you also have a UL listing on the drywall screw you use to hold up your one hole strap?
Posted By: Megawatt Re: Listed straps for MC? - 02/16/05 02:52 PM
Check out Cooper's "B-Line" products. They have the best selection for all of the different situations You will come across.
I have used the "Bat Wing" clips for attaching MC cable to the support wires for drop ceilings, & they work great.
http://www.b-line.com/product/Fastners/index.asp
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