stainless steel screws for box support agricultral building ?

[howardrichman]

I'm installing switch, outlet and lighting aluminum weatherproof boxes throught a horse barn. I'll be installing wet location type fixtures, and covers on all the devices. Would I have to use stainless steel screws to fasten the boxes, and pipe straps? I wouldn't use them on exterior work; unless the code referes to specific areas where there might be a corrosive atmosfere. Also; would the outlets and GFI's have to be rated outdoors near or at the stall areas? Will i need to ground toggle switches in metal boxes? I'll be installing a few paddlefans above the stall isles; cant find a commercial weatherproof fan. Will a standard unit pass inspection mounted to an approved wp fan box? All pvc piping, aluminum boxes, inspector will not allow EMT.


HR

 

[kwired]

Stainless fasteners would be ok but horse barns are typically pretty clean and not nearly as corrosive as other livestock buildings. A similar sized area that may house 10 horses may house 100 hogs or maybe 50 cattle. The horse barn will be cleaned more often also.

I haven't had a lot of trouble in general with galvanized fasteners in these areas. Sometimes the screws last longer than the material they are driven into, especially plywood - even if covered with glassboard.

 

[jumper]

Have a look at 547.

 

[howardrichman]

Stainless fasteners would be ok but horse barns are typically pretty clean and not nearly as corrosive as other livestock buildings. A similar sized area that may house 10 horses may house 100 hogs or maybe 50 cattle. The horse barn will be cleaned more often also.

I haven't had a lot of trouble in general with galvanized fasteners in these areas. Sometimes the screws last longer than the material they are driven into, especially plywood - even if covered with glassboard.

Thanks for reply; I cant see why EMT cant be used. 547.5 specifies: or other raceways or cables sutable for the location. Inspector feels EMT is not corrosion resistant, and is classifying the horse barn as an agriculture blding, and the state officials say the horse barn does,nt have a classification, and is wired based apon it,s enviremental conditions.

HR

 

[kwired]

Thanks for reply; I cant see why EMT cant be used. 547.5 specifies: or other raceways or cables sutable for the location. Inspector feels EMT is not corrosion resistant, and is classifying the horse barn as an agriculture blding, and the state officials say the horse barn does,nt have a classification, and is wired based apon it,s enviremental conditions.

HR

Living in a primarily agricultural area of the country, I have done a lot of work in 547 buildings. Those buildings usually happen to be exempt from inspection but I like to be as NEC compliant as possible anyway for my own liability. (No inspection means you are competing against people for business that may not follow codes, so you may be inclined to break a rule here or there)

I can tell you that a building housing horses are typically clean and not very corrosive environments as compared to buildings housing most other animals. The reason people have horses is a completely different reason than other animals, and they are cared for in a much different way, resulting in a cleaner/healthier environment for the horse.

I would have no problem running EMT in this building in areas that are not in close proximity to the horses or that get washed frequently. I also realize the AHJ may feel differently about this.

Although there are not any around here, horses that are part of big racing or big time shows, usually live in cleaner environment than some of the dwellings I get called to work in .

 

[weressl]

I'm installing switch, outlet and lighting aluminum weatherproof boxes throught a horse barn. I'll be installing wet location type fixtures, and covers on all the devices. Would I have to use stainless steel screws to fasten the boxes, and pipe straps? I wouldn't use them on exterior work; unless the code referes to specific areas where there might be a corrosive atmosfere. Also; would the outlets and GFI's have to be rated outdoors near or at the stall areas? Will i need to ground toggle switches in metal boxes? I'll be installing a few paddlefans above the stall isles; cant find a commercial weatherproof fan. Will a standard unit pass inspection mounted to an approved wp fan box? All pvc piping, aluminum boxes, inspector will not allow EMT.


HR

I would suggest that using SS screws with galvanized or cadmium plated steel hardware is actually more harmful than beneficial. The SS screws actually will force the mild steel to become sacrificial anodes and will corrode away. Unless it is at grade level, where splattering horse urine would be the corrosive initiator - electrolyte - between the dissimilar metals, your concern would be the evaporated fumes of the same. In high humidity areas it is accelerated, but as pointed out by others, the well enforced cleanliness of horsebarns will minimize this effect. Even if you use PVC conduit the copper and other conductive metallic parts within - where it really counts - will remain subject to corrosion,

 

[kwired]

I would suggest that using SS screws with galvanized or cadmium plated steel hardware is actually more harmful than beneficial. The SS screws actually will force the mild steel to become sacrificial anodes and will corrode away. Unless it is at grade level, where splattering horse urine would be the corrosive initiator - electrolyte - between the dissimilar metals, your concern would be the evaporated fumes of the same. In high humidity areas it is accelerated, but as pointed out by others, the well enforced cleanliness of horsebarns will minimize this effect. Even if you use PVC conduit the copper and other conductive metallic parts within - where it really counts - will remain subject to corrosion,

If it is in location where splattering horse urine is the source of corrosion it better be RMC, IMC, or better yet PVC coated RMC or physical damage will destroy it before corrosion does.

 

[howardrichman]

Living in a primarily agricultural area of the country, I have done a lot of work in 547 buildings. Those buildings usually happen to be exempt from inspection but I like to be as NEC compliant as possible anyway for my own liability. (No inspection means you are competing against people for business that may not follow codes, so you may be inclined to break a rule here or there)

I can tell you that a building housing horses are typically clean and not very corrosive environments as compared to buildings housing most other animals. The reason people have horses is a completely different reason than other animals, and they are cared for in a much different way, resulting in a cleaner/healthier environment for the horse.

I would have no problem running EMT in this building in areas that are not in close proximity to the horses or that get washed frequently. I also realize the AHJ may feel differently about this.

Although there are not any around here, horses that are part of big racing or big time shows, usually live in cleaner environment than some of the dwellings I get called to work in .

Thanks for reply; I'm just hoping aluminum boxes are adaquate and permisable in this location. I've used them in a few horse barns in the past w/ no problem w/inspection or corrosion, as you said, most horse barns are fairly clean.

HR...

 

[electricguy61]

Why not use PVC boxes? Wouldn't this would make the job as wash down proof as possible (within reason).

 

[howardrichman]

Why not use PVC boxes? Wouldn't this would make the job as wash down proof as possible (within reason).

The problem w/ pvc boxes is that their limited in use by their depth and # of entre ports to use for devices. If no device; Ide use a 4/4/2 pvc box. Carlon does make a threaded box but is shallow and harder to find.Carlon does make a non-port pvc box, but can only take one port entre per side. I'm using 5+7 hole Mulbury boxes houseing conduits from the slab, and exiting the top . I'm stil not sure if I need to use weatherproof GFI /outlets in that horse barn.

HR...

 

[ceb58]

Although there are not any around here, horses that are part of big racing or big time shows, usually live in cleaner environment than some of the dwellings I get called to work in .

That is a very true statment. All the ones I have done were dusty. The only area that was wet was the washing stall. Water is the last thing they want all over the barn due to causing hay and grain to mold.

 

[kwired]

The problem w/ pvc boxes is that their limited in use by their depth and # of entre ports to use for devices. If no device; Ide use a 4/4/2 pvc box. Carlon does make a threaded box but is shallow and harder to find.Carlon does make a non-port pvc box, but can only take one port entre per side. I'm using 5+7 hole Mulbury boxes houseing conduits from the slab, and exiting the top . I'm stil not sure if I need to use weatherproof GFI /outlets in that horse barn.

HR...

Maybe your suppliers just don't have much variety, I've seen most of the same port and depth combinations in both PVC as well as aluminum bell boxes.

 

[weressl]

The problem w/ pvc boxes is that their limited in use by their depth and # of entre ports to use for devices. If no device; Ide use a 4/4/2 pvc box. Carlon does make a threaded box but is shallow and harder to find.Carlon does make a non-port pvc box, but can only take one port entre per side. I'm using 5+7 hole Mulbury boxes houseing conduits from the slab, and exiting the top . I'm stil not sure if I need to use weatherproof GFI /outlets in that horse barn.

HR...

Your problem maybe more in the form of hosedown than the occasional driven rain under a covered structure. Some horsebarns are more like indoor heated areas when located in cold climate, where the air-exchange is forced by fans and not natural vetillation with more-or-less open sides.