Where appropriate to use armored electrical cable?

[NetWareHead]

Going to do some more rewiring soon and have a question about the appropriate use of armored cable vs non-metallic sheathed cable (aka romex). Looking at my electrician's previous work, remembering our conversations, was able to deduce the following.

-Exposed wiring: Needed to rewire a pull string light fixture in a closet. Location under a stairwell made impossible to fish the cable through walls & ceiling. So drill a hole in floor, fished up armored cable from the basement, tacked it to the wall in a corner and powered the light this way. My guess is that since the cable is exposed in a habitable portion of the house, it needs to be in either a conduit or armored.

-Wiring in dangerous location: Wired a barn and he said raw romex was not permissible due to combustibility of hay etc... Used combination of conduit and armored cable.

Im going to be rewiring a garage which kinda confuses me. It could be classified as dangerous due to presence of gasoline etc... It could be classified as habitable but then again, my entire basement is done in romex. So perhaps armored cable is the way to go as the most cautious route. I know I need to check my codes but so far i cant find anything about garages or whether garages are classified as habitable. (This is in NH if anybody knows...)

On a side note, what to you guys use to connect armored cable to a junction box? For instance with romex, use NM cable connectors you screw into the hole, then tighten a locknut to secure and then tighten 2 screws to clamp down on the incoming wire. What is the equivalent for armored?

 

[NutBucket]

For the closet I would use a surface mounted raceway:

http://www.homedepot.com/c/powering_fixutres_with_raceway_HT_PG_EL

I agree with you on the garage/basement/barn distinction. I know, generally speaking, properly installed (through studs, properly secured, etc.) Romex in open framing is fine. I guess there's no reason you couldn't install BX if you wanted to. I know you can't run Romex on the face of the studs, though.

 

[SparkyJJO]

There is a clamp that looks almost identical to a romex clamp, except it is for the armored cable.

The end has that lip that holds the plastic bushing in place that you put in to prevent the cut edge of the outer armor from chafing the wires.

 

[Herr Kutz]

In classified areas

 

[stormkroe]

Hopefully this helps. Basically, anywhere the wire is subject to mechanical injury. As for the barn, you should know that AC-90 is not allowed in buildings housing livestock because of the caustic nature of animal fluids and moisture.

Edit, this is an L-16 connector that we use for BX. The clamp is deep and gives a firm hold on the armor so you don't have to tighten so much and possibly damage the armor.

 

[natto fire]

Arlington makes a snap-in connector for armored cable, "MC" is what we call it. They are great when you have tons of it to terminate, but the connectors that SprakyJJO posted work just as well and are cheaper and available at hardware stores.

Stormkroe covered the rest of it. Romex can pretty much only be used behind walls or in joist pockets of unfinished basements. Around here, drops for receptacles and switches in unfinished basements are Romex sleeved in EMT.

I did a barn for a friend and just did it all in EMT. I prefer it for ease to reconfigure/add circuits, and I had loads of extra THHN laying around, so it made it cheap.

In your case, are you going to be drywalling the garage after wiring is complete? If not, I would go with MC. If your wiring will be tucked into a wall, then romex away. Around here, exposed romex is pretty much a no go unless it is up in rafters or ceiling joists.

 

[NetWareHead]

Saw my electrician and he confirmed the garage (according to state code) is not classified as a habitable area and is treated like a basement. Regular romex is permissible.

Wont be drywalling anything in the garage. Just replacing some ancient flourescent lights that barely work attached to some equally old cabling. 2 family house so will segregate the exterior lighting to the landlord panel, and each tenant's garage space will connect to their respective panel. Right now, the entire garage is wired to the LL panel.

 

[Greenman]

Saw my electrician and he confirmed the garage (according to state code) is not classified as a habitable area and is treated like a basement. Regular romex is permissible.

Wont be drywalling anything in the garage. Just replacing some ancient flourescent lights that barely work attached to some equally old cabling. 2 family house so will segregate the exterior lighting to the landlord panel, and each tenant's garage space will connect to their respective panel. Right now, the entire garage is wired to the LL panel.

Romex can't be used in a garage unless it's at least 8' off the floor or protected by drywall.

 

[Sukhoi]

Romex can't be used in a garage unless it's at least 8' off the floor or protected by drywall.

Where does the 8' come from? I have seen similar dimensions listed elsewhere, but never an actual source.

 

[NetWareHead]

Romex can't be used in a garage unless it's at least 8' off the floor or protected by drywall.

??? Maybe its a code difference between our areas? I'm in NH.

 

[NutBucket]

That would be my guess too.

 

[DrPizza]

This may help: http://ecmweb.com/code-basics/2011-nec-revisions-cable

 

[NetWareHead]

This may help: http://ecmweb.com/code-basics/2011-nec-revisions-cable

Thank you. Re: Non-metalic sheated cable

The 2011 Code answers a common question on the use of NM cable in dwelling unit accessory structures, such as detached garages. A detached residential garage isn’t a dwelling unit as defined in Art. 100. Therefore, a literal reading of 334.10(3) would require types NM, NMC, and NMS cables to be concealed within walls, floors, or ceilings using a material with a 15-minute finish rating, such as drywall. The 2011 NEC clarifies that the use of NM cable in all dwelling unit garages and accessory storage buildings without the 15-minute finish rating is allowed, if the cables aren’t subject to physical damage [334.15(B)].

 

[Greenman]

Where does the 8' come from? I have seen similar dimensions listed elsewhere, but never an actual source.

The inspectors around here universally use "subject to physical damage" as the reason why it has to be covered. They call 8' the line below which it can be damaged. I don't have any issue with it, it's prudent to cover it. Some inspectors are getting fussy about feeder cable and AC wiring running across the garage ceiling. I don't have an issue with that either, I can't tell you how many times I've seen three hundred pounds of crap hung from sub panel feeds.

 

[stormkroe]

Romex can't be used in a garage unless it's at least 8' off the floor or protected by drywall.

Wow, it's more strict in Canukistan:
CEC 12-518 Protection for cable in exposed installations (see Appendix G) Cable used in exposed wiring shall be adequately protected against mechanical damage where it passes through a floor, where it is less than 1.5m above a floor, or where it is exposed to mechanical damage.

 

[Sukhoi]

The inspectors around here universally use "subject to physical damage" as the reason why it has to be covered. They call 8' the line below which it can be damaged. I don't have any issue with it, it's prudent to cover it. Some inspectors are getting fussy about feeder cable and AC wiring running across the garage ceiling. I don't have an issue with that either, I can't tell you how many times I've seen three hundred pounds of crap hung from sub panel feeds.

Ah, interesting. Wish the NEC would just define the height that is "subject to physical damage" for residential garages so it is not open to interpretation.

 

[Joe C]

NetWareHead, Are permits needed in NH? If so, then the correct answer will be given to you from the inspector, so ask him. Getting responses from others with "around here such and such is accepted" means nothing, your building dept has the final say. Good luck in your project.

 

[NetWareHead]

NetWareHead, Are permits needed in NH? If so, then the correct answer will be given to you from the inspector, so ask him. Getting responses from others with "around here such and such is accepted" means nothing, your building dept has the final say. Good luck in your project.

I dont need a permit if performing work on my own property and would like to do all of this before the property rents out. I could permit it but I'd rather not get inspectors involved.

And thats not really how inspectors operate. They come to check out the final work and give you a pass/fail. Fail meaning I need to remove and start from scratch so I want to get it right before I begin. Sometimes you might catch an inspector on a good day and he will tell you where you screwed up but its not typical of them to offer advice on your project.

 

[NetWareHead]

The inspectors around here universally use "subject to physical damage" as the reason why it has to be covered. They call 8' the line below which it can be damaged. I don't have any issue with it, it's prudent to cover it. Some inspectors are getting fussy about feeder cable and AC wiring running across the garage ceiling. I don't have an issue with that either, I can't tell you how many times I've seen three hundred pounds of crap hung from sub panel feeds.

Thats the fly in the ointment. "Subject to physical damage". Yes the garage is not a habitable area and I wont drywall it. Could the cable be damaged? Could be. Installed lower than 8'? Yes.

Ah, interesting. Wish the NEC would just define the height that is "subject to physical damage" for residential garages so it is not open to interpretation.

Seriously. I want to do it by the book but when the book itself is kinda vague... Think I may end up doing it all with armored cable to go above and beyond and give me peace of mind for the future even if armored is more expensive...

 

[Greenman]

My guess is they want the inspector to be able to exorcise some judgement. If you have one piece of romex tucked in a corner feeding an outlet, probably not an issue. But if your running 6 outlets on 3 different circuits and your garage walls look like a poorly managed data center, he can make you cover it up.

 

[DrPizza]

My guess is they want the inspector to be able to exorcise some judgement. If you have one piece of romex tucked in a corner feeding an outlet, probably not an issue. But if your running 6 outlets on 3 different circuits and your garage walls look like a poorly managed data center, he can make you cover it up.

And, if it's attached to the residential structure, it's a good idea. I like the 8 foot rule, though I don't think that's the rule here. So many people store tools in the garage - it's not difficult to envision a shovel or chainsaw or something hung on the wall, falling just right to give a conductor a pretty good nick.

 

[Micrornd]

I dont need a permit if performing work on my own property and would like to do all of this before the property rents out. QUOTE]

Are you absolutely sure of that?

Here, you can do electrical work on your own primary residence, but any other property requires the use of a licensed electrician and a permit, absolutely if it is a rental property.

 

[NetWareHead]

I dont need a permit if performing work on my own property and would like to do all of this before the property rents out. QUOTE]

Are you absolutely sure of that?

Here, you can do electrical work on your own primary residence, but any other property requires the use of a licensed electrician and a permit, absolutely if it is a rental property.

Its my primary residence now. Its not a rental property yet

 

[Scarpozzi]

In my residence, I just finished a huge wiring project. I can't remember which codes I based everything, but I was able to use Romex in all applications except my feeder. I used 2-2-2-4 SER alumnium to drop 100amp service to my new attached garage and then branched off it for a bedroom, the garage, and a media room.

All circuits were romex and are on Ground Fault and/or Arc Fault combination type breakers.

If your wires aren't protected by the wallboard and stapled, you should consider the armored conduit. Rats, squirrels, raccoons, and other vermin can chew right through romex insulation. It's probably the biggest risk next to non-stapled romex rubbing against sharp corners and/or plastic insulation getting brittle over time. I've seen 40 year old wire literally flake apart in my hand leaving exposed wires after being exposed to years of extreme conditions and turning brittle.