The link to "Thomas & Betts", manufacturer of the "Steel City" brand is http://tnbelectricalworld.tnb.com/ps/con/
. Click on PRODUCT on the left or use the items in the grey box on the right to search the catalog. (They have some measurements in the catalog.)
The image below is from Pass & Seymour; one can use the measurements from this to figure out some of the measurements of the device box. (On second thought, perhaps not...)
For Pass and Seymour information, visit http://www.passandseymour.com/
and click on "Downloads."
P. S. The "average" metal box size is 3 inches tall by 2 inches wide. Depth can be from 1 1/2 inches to 3 1/2 inches.
[This message has been edited by ThinkGood (edited 08-04-2003).]