Wooden switch box

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ishium 80439

Senior Member
Location
Denver foothills via the Horn of Africa
I am helping to make a safety board showing a sampling of the things that we have actually found installed in the field. The idea is to re-create them and then to list the various Code violations to help explain to people why the installations are dangerous. One of the items we would like to use is an installation where we found a light switch enclosed in a box made out of wood- just some scrap lumber they must have had laying around. Oddly enough I'm having a tough time finding good NEC references for this.

The closest I've come is 110.3 "Listed or labeled equipment shall be installed..." and 404.3(A) "Switches... shall be ... mounted in an enclosure listed for the intended use...". It seems that I must be missing something if this is the strongest arguement that I can come up with against constructing your own box out of 1x lumber. The only other thing I can think of is 110.8 "Only wiring methods recognized as suitable are included in this Code" which I could interpret as "a wooden box is so far outside of what would be considered correct why are we even discussing it?"

So what am I missing?

Thanks
 
dhalleron

dhalleron

Senior Member
Location
Louisville, KY
I guess you could argue there is some arcing going on inside the switch and it is not completely sealed to contain the arc.

NFPA 70 2011
110.18 Arcing Parts. Parts of electrical equipment that in
ordinary operation produce arcs, sparks, flames, or molten
metal shall be enclosed or separated and isolated from all
combustible material.

I'm sure someone else will find a better example.
 
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ishium 80439

Senior Member
Location
Denver foothills via the Horn of Africa
I was thinking of 110.18 and may still use it but was discouraged when I read the Handbook commentary that listed examples such as "open motors having a centrifugal starting switch, open motors with commutators and collector rings." It could still work for me though as most people aren't really going to take the time to dissect it and it's not as if I'm making a display for a court case that has to be bullet proof- I think I can take some "poetic license" :D
 
H

Hendrix

Senior Member
Location
New England
"a wooden box is so far outside of what would be considered correct why are we even discussing it?"

That pretty much sums it up :happyyes:
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Hendrix said:
I wonder who lists those.
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Notice they shipped from Thailand, so I guess it's ULt :D:D

(paraphrasing someone's signature here... anything can be listed if the plans are drawn on a big enough check)
 
kwired

kwired

Electron manager
Location
NE Nebraska
ishium 80439 said:
I am helping to make a safety board showing a sampling of the things that we have actually found installed in the field. The idea is to re-create them and then to list the various Code violations to help explain to people why the installations are dangerous. One of the items we would like to use is an installation where we found a light switch enclosed in a box made out of wood- just some scrap lumber they must have had laying around. Oddly enough I'm having a tough time finding good NEC references for this.

The closest I've come is 110.3 "Listed or labeled equipment shall be installed..." and 404.3(A) "Switches... shall be ... mounted in an enclosure listed for the intended use...". It seems that I must be missing something if this is the strongest arguement that I can come up with against constructing your own box out of 1x lumber. The only other thing I can think of is 110.8 "Only wiring methods recognized as suitable are included in this Code" which I could interpret as "a wooden box is so far outside of what would be considered correct why are we even discussing it?"

So what am I missing?

Thanks
Click to expand...

I think you pretty much got all the NEC is going to give you. If you want to know what it takes to get a switch box listed you might want to see what UL (or other NRTL) requires to give a switch box a listing. The construction lumber probably does not meet those requirements.
 
kwired

kwired

Electron manager
Location
NE Nebraska
K_Buz said:
You could cite 314.20 since wood is a combustible material.
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314.20 does not apply to the construction of the box just the installation of it. IF you were able to find a listed box constructed of wood 314.20 would still apply to its installation.
 
K

K_Buz

Member
Location
Southeastern Wisconsin
True, but you could draw the conclusion that if the box was to be installed to protect combustible building materials, the box itself couldn't be made from combustible materials.
 
kwired

kwired

Electron manager
Location
NE Nebraska
K_Buz said:
True, but you could draw the conclusion that if the box was to be installed to protect combustible building materials, the box itself couldn't be made from combustible materials.
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Plastic boxes are combustible - just not as easily combustible as wood, and the ones we do use are listed for the purpose.
 
acrwc10

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
kwired said:
Plastic boxes are combustible - just not as easily combustible as wood, and the ones we do use are listed for the purpose.
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Most plastic boxes have a 2 hour fire rating in the wall and 1 hour in the ceiling, I don't know how long in the floor,,,,,,
 
stevebea

stevebea

Senior Member
Location
Southeastern PA
acrwc10 said:
Un-flippin believable. :jawdrop::slaphead::dunce:

Really makes you wonder how many people die in 3rd world countries due to things like that, that you wouldn't have happen here.
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Hv&Lv said:
Want to buy some new ones?
http://www.ebay.com/itm/TEAK-WOOD-E...=320749779741&ps=63&clkid=7528533587885215401
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A year ago in the Dominican Republic I saw a receptcale mounted in a hand crafted wooden " handy box " fed with an extension cord. Never imagined I would see a listing like the one posted on ebay!
 
kwired

kwired

Electron manager
Location
NE Nebraska
acrwc10 said:
Most plastic boxes have a 2 hour fire rating in the wall and 1 hour in the ceiling, I don't know how long in the floor,,,,,,
Click to expand...

Pretty much anything will burn if you get it hot enough and there is oxygen to react with. In order for that box to last 2 hours it needs to be in drywall, masonry, or some other low combustible finish or it will go about as fast as the finish.
 
kwired

kwired

Electron manager
Location
NE Nebraska
JDB3 said:
Isn't there an article that the "approved box" has to mounted, so that a max. of 1/4 inch of ignitable material is exposed or something like that?
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Just the opposite. 1/4 inch of non combustible material exposed if the box is not flush. If the wall finish is combustible material the box must be flush. See 314.20.
 
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