A cable mounting system that allows thermal expansion and contraction of cables. The cable mounting system includes straight ladder rack segments and widened ladder rack segments positioned adjacent the straight ladder rack segments. Cable bracket assemblies are mounted to the straight ladder rack segments and saddle bracket assemblies are mounted to the widened ladder rack segments. The cable bracket assemblies secure cables to the ladder rungs of the straight ladder rack segments and allow axial movement of the cables. The saddle bracket assemblies secure the cables on the ladder rungs of the widened ladder rack segments and allow axial and lateral movement of the cables.