How many .25 inch diameter control cables can be installed in a 6 inch wide trough cable tray with sides 6 inches high?

Solution:

Area of cable tray cross section = 6 x 6 = 36 square inches.  Allowable area at 50 % fill = .5 x 36 18 square inches.

Area of one cable = (.25/2)x (.25/2)(3.14) =.05 square inches Number of cables = 18/.05 = 360 cables