Horse Barn Wiring Methods

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shortcircuit2

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First, would you consider a barn on residential property for boarding horses an agricultural building subject to the provisions of 547? I say yes...

Then would romex (typeNM) be an acceptable wiring method within the walls of the barn, which is of wood construction, and the romex (type NM) in the wood frame walls will be concealed by a wall finish of WOOD also?

Now, where it is concealed within the walls, the romex will not be subject to physical damage, a corrosive atmosphere, or a wet or dusty environment.

So, the above conditions seem to allow romex (type NM) as a wiring method.

But...then I look to 334.10(3) which states that when romex is used in OTHER BUILDINGS it is to be; "Concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies."

So since the finish wall concealing the romex is wood, which would not have a 15-minute fire rating...334.10(3) seems to prohibit romex (type NM) as a wiring method?

What do you say?

shortcircuit2
 
Re: Horse Barn Wiring Methods

It doesn't take very thick wood to give you the 15 minute flash rating. A 15 minute rating is defined as 1/2" gypsum board or equivalent. Among the equivalent materials are 5/8" plywood or 1" x 6" T&G.
 
Re: Horse Barn Wiring Methods

As I see it 547.5 is applicable and it does not distinguish between exposed or concealed wiring methods. Type NM is not listed amongst the recognized wiring methods under this section.

Type NMC (corrosion resistant outer sheath) is listed but I do not believe it is readily available. Type UF seems to be the cable method of choice and it is listed amongst those in 547.5.

installation requirements are also established in 547.5 and 6.

547.1 applies to agricultural buildings or parts of buildings or "adjacent areas of similar or like nature as specified in 547.1(A) and (B)."(NEC)

Many would consider any shelter used to house livestock of the type indicated to at least conform to (B) as a corrosive atmosphere , and in that case 334.12(10) would not allow the use of NM-B.

Charlie
 
Re: Horse Barn Wiring Methods

Hey Charlie...have seen you post in some time.

Thats the way I interpret it also...but some I have talked with say many barns are wired with romex that is concealed.

Now, 334.12(10) described hazardous (classified)locations. The horse barn would have to be classified by the AHJ for that to apply, right?

334.12(B)(1) describes corrosive fumes or vapors.
Would horse excrement cause a corrosive condition in the walls of a horse barn where the wire is concealed? The wood walls are 1" thick T+G boards...

shortcircuit2
 
Re: Horse Barn Wiring Methods

Hi Shortcircuit

we have been real busy with 15 hour courses I'm just coming up for air now.

Thanks for pointing out the .(10) error

As I interpert 547 there is not a difference between concealed or exposed in the .5 paragraph ( but I'm willing to listen). If there is going to be droppings there is corrosive fumes and fumes travel every-where. This is another one of those issues that could get kicked around for hours at a IAEI meeting but the Code states what it states and I thing thats how I read it.

Charlie
 
Re: Horse Barn Wiring Methods

Charlie...thanx for kickin this issue around with me.

The only part of 547 that might grant exception to the use of romex (type NM) in the wall concealed would be 547.1 (scope)

"The provisions of this article shall apply to the following agricultural buildings or THAT PART OF A BUILDING or adjacent areas of similar or like nature as specified in 547.1(A) and 547.1(B)"

Now, the part of the building I am addressing is concealed within the walls of the agricultural building. Is this really subject to the conditions of 547.1(A) or 547.1(B)???

Does horse excrement cause enough harmful vapors to cause damage to wiring concealed in a wall???

547 does not distinguish between concealed or exposed when applying the allowed wiring methods of 547.5 I do agree with that...

An adjacent area of a the building may need a 2 hour fire rated wall to really be considered separate from the area where the livestock is housed...

Maybe over the life of the barn, when its walls become riddled with holes from the horses kicking and knawing at those wooden walls concealing the romex , hazards will develop, and this is reason for disallowing romex (type NM) as a wiring method within the walls of an agricultural building.

shortcircuit2
 
Re: Horse Barn Wiring Methods

Standard practice has been to run type UF exposed in barns and to only have to protect it when there is a physical damage problem. The requirement in 334.10(3) seems to be an oversight or utter cretinism because I am most certainly allowed to run open wiring on insulators in barns and industrial mill buildings.

If my AHJ says that I have to stick UF behind type X drywall what I will do is to rerun the wiring as open wiring on insulators and make him take it.
 
Re: Horse Barn Wiring Methods

cpal, I see that your .(10) quote came from the 2002 NEC. They rearranged 334 and moved that .(10) requirement to a the new 334.10(B) for 2005...

mc5w...Article 398 wiring methods has been dropped from 547.5 for 2005. You see UF wiring methods installed in barns in your area? Any romex?

I'm refering to the 2005 NEC here...should have said that...

shortcircuit2
 
Re: Horse Barn Wiring Methods

Several Horse confinement (stables)buildings in my area all are wired with wiring methods listed in 547.5.
If an argument can be made for a separation of buildings then I would accept alternate wiring methods. This is dynamic and would need consideration for each installation.
 
Re: Horse Barn Wiring Methods

Does horse excrement cause enough harmful vapors to cause damage to wiring concealed in a wall???
Click to expand...
Harmful vapors from road apples? What are you fellas feeding your horses? :D

I think there are only a couple issues when it comes to horse structures, IMO. Hay dust, kicking & cribbing.

Horses are killed by romex every year, usually by chewing on it. Keep it out of reach, and they can't chew on it.

I have no idea how to prevent haydust from accumulating in panels. I've seen barns a couple years old with a quarter inch or better of dust in there. I'd imagine there's some equipment from the commercial sector out there that would be overkill but ideal, and I imagine gasketing would help for a little while.

As far as kicking goes, the chances of a horse kicking through a well-built wall and discovering romex, and then hurting itself with it, pretty astronomical if a little common sense is used.
 
Re: Horse Barn Wiring Methods

georgestolz, thanx for the input...so, by the tone of your opinion, you don't see any problem with romex behind a well built wall out of reach of horses in a horse barn...

I live in a thickly settled bedroom suburb and wasn't raised on the farm...so I'm not familiar with the corrosive environment, if any, that horse chit and urine can create...

I have been told as you've said that horses will chew on most anything within there reach...a good reason to keep romex or UF wiring methods out of a barn...

Also, some have said mice, chipmunks and squirrels are likely become unwelcome residents of barns. They are known to chew into romex and UF wiring methods, creating fire hazards...

So, IMO any unprotected wiring method in a barn is subject to damage. I think a wiring method such as metal clad is best for concealed locations and RNC, RMC, IMC, suitable MC, and suitable EMT for exposed wiring methods.

IMO, older barns with unclassified wiring methods, AFCI protection of the wiring would help to prevent may horrible fires each year.

shortcircuit2
 
Re: Horse Barn Wiring Methods

IMO, older barns with unclassified wiring methods, AFCI protection of the wiring would help to prevent may horrible fires each year
Well the horses do sleep there :D
 
Re: Horse Barn Wiring Methods

Check out this link and this one which I found by a Google search.


Equus:
Frayed wiring, short circuits and other electrical problems cause one out of every seven barn fires.
Click to expand...
A different source:
These same experts say that 80-85% of horse barn fires are caused by electrical malfunctions or by human error and carelessness (smoking, forgetting a water-bucket heater, overloading electrical connections, etc.)
Click to expand...
That last quote tickles me: It's about as useful a statistic as "100% of horse barn fires in some way involve flame, combustion, electricity, and/or human contact."

After further review, I suppose conduit is a far superior way to wire a horse barn. I've always presumed my mice are far busier eating the grain and hay cubes to chew on the romex in the ceiling, but perhaps I'll swap that out. Besides, mice can chew through steel and concrete, so I never figured EMT was much of a defense. But it's better than NM. :)

I am still inclined to agree with Equus, in that most barn fires are started by storing damp hay. But a little overkill can't hurt.

I think throwing AFCI's at the problem won't do any good at all, but that's just my opinion. I think most electrically started fires are negligent behavior or abused/chewed extension cords, which AFCI's are powerless to prevent.
 
Re: Horse Barn Wiring Methods

Great links to information on hazard prevention in barns georgestolz...thanx

A movie I saw in my 15 hour review 3 years ago showed the arcing hazards associated with abused extension cords and I was taught that AFCI breakers were designed to help prevent fire hazards from this problem.

Whether it be an extension cord, romex or UF cable that has been abused/chewed by a rodent or from other reasons, I thought that AFCI protection was designed to interrupt the power to the branch circuit wiring during an arcing fault...

Hence my reasoning in applying them to improper wiring in a barn for protection from such hazards...

Here is a link to wiring methods in barns in Minnesota...

http://www.electricity.state.mn.us/El_codes/Ecs_bull/AG_CHART.html

shortcircuit2

[ June 13, 2005, 05:03 AM: Message edited by: shortcircuit2 ]
 
Re: Horse Barn Wiring Methods

Originally posted by shortcircuit2:
Whether it be an extension cord, romex or UF cable that has been abused/chewed by a rodent or from other reasons, I thought that AFCI protection was designed to interrupt the power to the branch circuit wiring during an arcing fault...

Hence my reasoning in applying them to improper wiring in a barn for protection from such hazards...
Click to expand...
If your mouse is kind enough not to get electrocuted before he makes it through two conductors. :)

The AFCI's we have now wouldn't detect the series arc of one damaged conductor, and wouldn't detect cord problems at all, if memory serves. :)
 
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