Thomas & Betts 644 4-GANG CAST IRON FLOOR BOX

148 cubic inches of box volume. That is what you work from when you run the box fill calculation for the conductors, devices and grounds landing in a 4-gang floor box, so you can size the number of circuits before the pour.

No knockouts. The 644 ships with zero knockouts, so the conduit entries get drilled and tapped in the cast iron body where your raceway actually lands. Plan the entry locations with the electrician before the box is set, because you cannot punch cast iron the way you would a stamped steel box.

Just the box. The 644 is sold each, as the 4-gang cast iron body only. The service cover or carpet flange, the device plates, the receptacles or data jacks, and any fittings for the conduit entries are all ordered separately. Budget those into the job before you order.

The 644 is a cast iron body, which is the material used where the box gets buried in a concrete pour and has to take the weight of the wet concrete and the traffic above it without deforming. Stamped steel and nonmetallic floor boxes are lighter duty and generally go in wood-frame or raised-floor work. If you are setting a box in a slab on a commercial job, cast iron is the one the spec normally calls for.

It's a flush service floor box. The body sets below the finished floor and the service cover finishes level with the surface, so nothing stands up in a walking path. That is what makes it usable in an open office or lobby floor rather than a poke-through style assembly.

The 644 is a 4-gang body, which gives you four device positions in one box, and that is how these get used for a mixed power and communications floor service. Keep in mind the box itself is a single open volume of 148 cubic inches, so if you need physical separation between line voltage and data you have to add the appropriate barrier or divider; it is not built into the box.

Treat that as a field measurement, not an assumption. Cast iron floor boxes vary in footprint and depth between manufacturers and between gang counts, and the 644 is a 4-gang body. Pull the old cover, measure the rough opening and the depth to the conduit stubs, and match the conduit entry positions, since the 644 has no knockouts and every entry gets drilled and tapped to suit.