Trumbull Floor Boxes are designed for installation in concrete floors or slabs to provide support for extension stems of the non-rising type, and to provide a cover for the operating nut on the extension stem.
      Trumbull cast iron floor boxes are designed for varying slab thicknesses. Overall length is 6", but the underside is tapped to accept 2-1/2" NPT steel pipe nipples for floors thicker than 6". When necessary to convert a floor box to thicker floors, use a 2-1/2" pipe nipple 1/2" longer than the increase required as the threads on the underside of the floor box are 1/2" deep. For example, for an 8" floor thickness, use a 2-1/2" x 2-1/2" nipple. For a 10" floor, use a 2-1/2"x 4-1/2" nipple.
      All Trumbull Floor Boxes are furnished with a removable bronze bushing which allows the opening to be drilled up to 2-1/4" Dia. However, when used with floors thicker than 6", clear opening is limited to the I.D. of the pipe nipple.
      When threading in a pipe nipple, maximum bushing I.D. is 2-1/2", which will accept up to 2-3/8" O.D. solid rod, or 2" steel pipe.When the thickness of the floor is greater than 6" and when the bushing must be drilled larger than 1-7/8", a 3" pipe nipple will be welded to the bottom of the floor box.

Ordering Information:
I . Quantity
2. Thickness of floor slab.
3. O.D. of stem being used, or desired bushing hole size (15/16" D. supplied if not specified.)

See separate literature on Trumbull Extension Stems, Stem Guides and Mud Valves.
   

Typical Floor Box installation.