Anybody work with with MC Cable?

[64dragnwagon]

I just had a pole building built and I have to wire the whole thing. It is a commercial use building and the use of conduit or mc cable is required. I have done a lot of elect. work with romex in residential but no conduit or mc. I don't like the idea of having to cut and bend all that conduit. My electrician who is installing the main service and circuit panel suggested MC Cable. The walls will be unfinished for now and covered sometime down the road in a few yrs.
How hard is mc cable to work with? Looks are not my first priority, getting it done quickly, safely, passing inspection and getting my certificate of occupancy are the main priorities.

 

[PRH44]

I would prefer conduit but...
MC cable is very easy. Use the correct tools and you will have no problems. to strip the metal cladding I prefer this.

 

[PRH44]

Familiarize your self with NEC ART. 330 Not much to it here are the support highlights.
Support the cable at no greater intervals than 6 foot .
Support with in 12" of a box, fitting or cabinet.

 

[PRH44]

Although the NEC does not have a requirment for anti-short bushings for MC cable I strongly recommend using them

 

[PRH44]

You can use one hole straps for the diameter of the cable you are going to use.

I prefer the B-line cooper BX4M. it can be mounted many different ways. You can run two cables at a time or break it in two and run one cable. I always use the BX4M and leave it in tack when running one cable for future installs.

 

[rabidsquirrel]

You can also use tape to create your own bushing, and you can cut the jacket with a hacksaw too. The rotosplit is much easier though.

 

[64dragnwagon]

Although the NEC does not have a requirment for anti-short bushings for MC cable I strongly recommend using them

Yes, my electrician told me about these bushings. Another question I have is are there different types of mc cable like aluminum VS steel? How much are the cutting tools like pictured in a previous post? Thanks for the input guys.

 

[64dragnwagon]

Also are there any special connectors for making right angle turns or do you just have to have a gradual bend. I have dealt with this in an old house I remodeled when I removed some and replaced with romex and it doesn't seem like it will bend at a sharp angle without kinking. Any body have any pics of mc cable installed in their building?

 

[PRH44]

As connectors go there are many types available. I prefer a set screw tyle with locknut such as the arlington saddle grip SG38A.

.

The snap in styles will work. I would not recommend them to a DIYer as they are a one shot deal. We use them often in the commericial market. The current high productivity demands in the construction industry has spawned a number of them. Such as the Arlington 40AST

The most important detail for connectors is selecting the proper size for the cable used. there are ends stop diameters that very per connector. This is the shoulder that stops the metal clad and allows the conductor to pass through. You can take a look at the Arlington sight

http://www.aifittings.com/catalog/flex-ac-mc-fittings/

 

[PRH44]

Also are there any special connectors for making right angle turns or do you just have to have a gradual bend. I have dealt with this in an old house I remodeled when I removed some and replaced with romex and it doesn't seem like it will bend at a sharp angle without kinking. Any body have any pics of mc cable installed in their building?

They make 90 degree and 45 degree connectors take a look at the Arlington link. they even make a swival connector.

http://www.aifittings.com/catalog/flex-ac-mc-fittings/

 

[PRH44]

Yes, my electrician told me about these bushings. Another question I have is are there different types of mc cable like aluminum VS steel? How much are the cutting tools like pictured in a previous post? Thanks for the input guys.

There is a steel jacket and an aluminum jacket versions. The aluminum is lighter and easier to work with. It also damages easier. Becareful using MC cable exposed below 8 to 10 feet as it can get damaged easily. You should use conduit below that level. EMT will work fine for drops in your shop.

The cutters are about 30 bucks

 

[PRH44]

Each roll of cable will come with a bag of antishort bushing attached. They are cheap

 

[OldracerJones]

Thanks for asking the question as I am going to wire my 50'x 30' metal building with MC based on many comments here that you shouldn't use romex in a metal building without conduit. I figure MC is just as easy as putting conduit up. I had all the questions you had so thanks to all for the comments.

 

[64dragnwagon]

Thanks for asking the question as I am going to wire my 50'x 30' metal building with MC based on many comments here that you shouldn't use romex in a metal building without conduit. I figure MC is just as easy as putting conduit up. I had all the questions you had so thanks to all for the comments.

It's got to be a LOT easier than conduit. I can only imagine the amount of labor it would take to do the whole building (30x60) in metal conduit. Especially when I have never done it and bending conduit is a learning curve I am sure.

 

[green.bubbly]

I used the MC and other than a few initial rookie mistakes, it was easy to work with considering I never touched the stuff. Below is a link to my MC fail thread. It is full of information including my mistakes and all the great help I received from a few great guys around here.


http://garagejournal.com/forum/showthread.php?t=104081

 

[cderalow]

It's got to be a LOT easier than conduit. I can only imagine the amount of labor it would take to do the whole building (30x60) in metal conduit. Especially when I have never done it and bending conduit is a learning curve I am sure.

once you get the hang of bending conduit, it's actually really easy, and probably just as fast as running MC or romex

 

[sberry]

There may be places for the cable, to dead end outlets ets, maybe some swtich loops but conduit allows for running more than one circuit, multiple wires, switch loops etc. Many cases it eleminates a lot of extra wires.

 

[PRH44]

I would always prefer conduit, it is far more versatile than cable. With that said if you really want to use MC cable it is available in 2,3,4,and 8 wire configurations. However 4 and 8 wire may not be available at the box stores..

 

[KenC]

I don't have a pic handy, but my preferred connector is a screw in type. It has external ridges that act as threads and insert inside the metal and over the conductors. It positively protects from damaging the cable with the cladding, like the antishort bushings, but better. It's fast and looks neat when installed. Since I don;t do this often, and being a cheap b+++++, I cut the metal with a pair of dykes. Just use the very end and nip the clad across one turn.

 

[sberry]

It's got to be a LOT easier than conduit. I can only imagine the amount of labor it would take to do the whole building (30x60) in metal conduit. Especially when I have never done it and bending conduit is a learning curve I am sure.

This is not a huge building, A little planning and imagination and the basics could likely be piped in a day or 2 especially with a helper, maybe run some MC to fixtures, this whole scheme might be done in stages to some extent. I often hoard up enough basic materials as something comes up or as I need it I can reach in to the pile and run an extension or circuit.

 

[64dragnwagon]

Help me out with this. Why does it seem that most here are not a fan of MC Cable? I don't understand why conduit is so much better. mc is the same except the "conduit" is flexible. I understand that conduit looks cleaner IF DONE RIGHT but are there any advantages other than appearance? Thanks for all the input.

 

[MrMark]

I've recently done a bunch of mc cable, for vermin reasons. Of course, conduit (if exposed) is much better because it is safer and more flexible in terms of repulling if needed. In fact, MC cable and romex both stand the same in the eyes of the code in terms of requiring protection from damage.

 

[Falcon67]

I'm going to run MC instead of conduit in most places on the surface. I bought 100' of it and damned if I can find any other use for it, so that's what I'm going to do with it! I've cut 8' off that roll of MC but used over 800' of Romex.

 

[green.bubbly]

Help me out with this. Why does it seem that most here are not a fan of MC Cable? I don't understand why conduit is so much better. mc is the same except the "conduit" is flexible. I understand that conduit looks cleaner IF DONE RIGHT but are there any advantages other than appearance? Thanks for all the input.

I have limited experience with both. The flex cable is not as durable in my opion as it is fairly easy to smash.

You can also run multiple wires/circuits in conduit. I am not sure if you can do that with flex. That is all I can think of.

 

[64dragnwagon]

I've recently done a bunch of mc cable, for vermin reasons. Of course, conduit (if exposed) is much better because it is safer and more flexible in terms of repulling if needed. In fact, MC cable and romex both stand the same in the eyes of the code in terms of requiring protection from damage.

Not true in my area anyway. My licensed electrician said that I can NOT use romex in a commercial building, he said it has to be "protected" meaning either conduit OR MC Cable.

 

[MrMark]

Not true in my area anyway. My licensed electrician said that I can NOT use romex in a commercial building, he said it has to be "protected" meaning either conduit OR MC Cable.

I don't know about commercial installs. AFAIK, nm is not allowed in commercial, so your comment doesn't really address my point. According to the NEC code, there is no difference between MC and NM in this regard to the requirement of protection. They both require protection from damage. In other words they can't be run exposed where people could damage them. There seems to be some that thing mc cable is OK to be run exposed but romex isn't, but there is nothing in the code book to back them up.

MC cable is not "protected" and does not supply protection according to the NEC. MC cable REQUIRES protection, so either you misunderstood the electrician or he just didn't know. I'll give a cite if you don't believe it. As far as I am concerned, there are only a couple reasons to use it. One, it looks better than nm when run exposed (where allowed like up high) in a garage and two, it protects against rats and mice. That's it. It is harder to work with, more costly, has poor bending radius, is much more subject to installation error, and provide very limited enhanced protection over nm, as recognized by the code.

 

[64dragnwagon]

I don't know about commercial installs. AFAIK, nm is not allowed in commercial, so your comment doesn't really address my point. According to the NEC code, there is no difference between MC and NM in this regard to the requirement of protection. They both require protection from damage. In other words they can't be run exposed where people could damage them. There seems to be some that thing mc cable is OK to be run exposed but romex isn't, but there is nothing in the code book to back them up.

MC cable is not "protected" and does not supply protection according to the NEC. MC cable REQUIRES protection, so either you misunderstood the electrician or he just didn't know. I'll give a cite if you don't believe it. As far as I am concerned, there are only a couple reasons to use it. One, it looks better than nm when run exposed (where allowed like up high) in a garage and two, it protects against rats and mice. That's it. It is harder to work with, more costly, has poor bending radius, is much more subject to installation error, and provide very limited enhanced protection over nm, as recognized by the code.

Thanks, I would appreciatte if you could put a link to the site. I am not saying you are wrong I am saying that I have had 2 electricians tell me the same thing. Why is it not as protected as conduit? It is metal just like conduit. I will call the electrical inspector in my county and ask him myself so I know I am hearing it from the horses mouth. My electrician told me that I can't use romex even if the walls are covered after installation like in my finished office with drywall his reason is it is commercial.

 

[MrMark]

OK, I'll get you the cite. Again, you can't use romex in commercial. I see your issue though where you are thinking that this mc stuff must be better code wise. But . . .

I'll get you the cite.

 

[MrMark]

330.12 MC not permitted where subject to physical damage.

Same as nm cable.

 

[Norcal]

OK, I'll get you the cite. Again, you can't use romex in commercial. I see your issue though where you are thinking that this mc stuff must be better code wise. But . . .

I'll get you the cite.

The use of NM cable will vary by where you are, some MA electricians were showing NM cable installs in grocery stores, (damn ugly too) & also have mentioned that they are used for 480V too, what has driven NM out of the commercial market here is when the NEC stopped allowing NM above a suspended ceiling in non residential applications, IMO, it was fine for smaller non-medical office buildings & such, for medical even MC is not allowed, because of grounding requirements, EMT or a so-called "healthcare" cable is required, which is a AC cable w/ a 12 AWG aluminum bonding conductor in additional to a insulated grounding conductor. Armored cable, AC does have a bonding strip unlike MC.

 

[walrus]

What code section says you can't use Romex (NM-B) in commercial work?

 

[Norcal]

What code section says you can't use Romex (NM-B) in commercial work?

It really has a lot to do w/ the building construction type as defined by the building code, some things have changed a lot, in the 1965 NEC concealed knob & tube was permitted for a place of assembly...... (Now requirements are strict as any mishap happening where a large group of people are gathered could be a disaster).

 

[Thruxton]

I've recently done a bunch of mc cable, for vermin reasons. Of course, conduit (if exposed) is much better because it is safer and more flexible in terms of repulling if needed. In fact, MC cable and romex both stand the same in the eyes of the code in terms of requiring protection from damage.

Ditto that- I rewired my attic using MC because of vermin (I rewired because the old BX was in very scary shape), but I'm in the middle of rewiring my shop with EMT.

 

[walrus]

It really has a lot to do w/ the building construction type as defined by the building code, some things have changed a lot, in the 1965 NEC concealed knob & tube was permitted for a place of assembly...... (Now requirements are strict as any mishap happening where a large group of people are gathered could be a disaster).

Places of assembly are one small section of commercial work. We both know Romex is used all the time in commercial work depending on where one is and what type of commercial work is being done

 

[PRH44]

Norcal is correct local building codes normally decide where romex is allowed to be installed. NEC states romex cannot be installed above a dropped or suspended ceiling in structures other than dwelling units.
Some cities I have worked will only allow romex in wood structures under 4 stories. Not permitted in a steel building.
In any location one opts to install romex metallic materials can be be dangerous. Steel decking has sharp edges, metal studs are very sharp, etc all which can easily damage romex during and after installation.
This is where MC cable and or conduit performs better. Although you must protect both NM cable and MC cable from physical damage. MC cable is more resilient against cuts.

The definition of "Subject to physical damage" is up for interpretation.
If you install MC cable on the wall where it could be smashed with carts, mobil benches and the like. Most would consider this "subject to physical damage. Say you install it on the ceiling out of the way. This would not be subject to damage. If you could lift something and smash it, would it be subject to physical damage? Maybe if you frequently lifted equipment in that area.

EMT can not be installed where "subject to severe physical damage". Say EMT is installed in the same places as the above example. Would it be subject to severe physical damage or just physical damage? If you could hit it hard enough to smash it?
What if one could roll a heavy object across the building, one that could develop large forces. Would anything mounted on the wall be subject to Severe physical damage?
Sometimes the NEC does not have all the answerers.

 

[64dragnwagon]

This is a pole building with metal siding and roof. 3/4th of the building will be used for auto repair. I plan on running the mc along the top of the 2x4 girts and in the gap between the poles and the metal siding. There is radiant barrier on the inside of the metal. I will not be using sheeting at this point but may add later (not before inspection). Mounted like this a horizontal impact coming from the inside of the building is really not possible or likely.

 

[PRH44]

64dragnwagon Installing your cable on top of the 2 X 4 sleeper is the best place for protection. If you install sheeting latter that will seal the deal. Good luck with your new venture and above all enjoy!

 

[wyliesdiesels]

I would prefer conduit but...
MC cable is very easy. Use the correct tools and you will have no problems. to strip the metal cladding I prefer this.

these work great as well:

http://www.homedepot.com/p/Klein-Tools-All-Purpose-Shears-and-BX-Cutter-1104/100630723

 

[Norcal]

The Roto-Split tool is the best choice, used a Klein version & was not impressed, & it's better to use a tool designed for the purpose, rather then snips, dykes, or other tools.


Edit: The Klein version of the Roto-Split.

 

[awdblazer]

better check local codes as code here is you must use antishorts