Oil-Filled XFMR Outdoors

[charlie b]

450.23(B) has me confused. An oil-filled transformer will serve a new building. The transformer will be outside, in an area well (i.e., below grade, covered by a grating but still open to the air above). There will be an overhang above the area well, one floor above grade (i.e., the floor of level two will extend over the opening). I don?t yet know what type of fluid will be used, so I can?t design this in accordance with the listing requirements of the fluid.

Is this even going to be allowable? Will I need a fire sprinkler system above the transformer, to protect the second level overhang from a possible fluid fire? Where do I go for information?

 

[erickench]

Charlie NEC 450.23(B) references NEC 450.27. This particular NEC section has a list of safeguard measures in cases where transformer installation presents a fire hazard. They are:

1) Space separations
2) Fire-resistant barriers
3) Automatic fire suppression systems
4) Enclosures that confine the oil of a ruptured transformer tank

If there is an overhang extending from the second floor then you might have satisfied the space separation requirements.

 

[mcclary's electrical]

http://www.youtube.com/watch?v=fzbQjd_Oo4Q



Look closely when the oil sprays out,,,,,,it's pretty much a flame thrower

 

[erickench]

Charlie, there's a fine print note under NEC 450.27. It state's:

FPN: For additional information on transformers installed on poles or structures or underground, see ANSI C2-2007, National Electrical Safety Code.