Grommet Wires less than $^{3}$/8" from hole edge Clearance $^{3}$/8" minimum A. Cushion clamp at bulkhead hole B. Cushion clamp at bulkhead hole with MS-35489 grommet Cable clamp MS-21919 Angle bracket with two-point fastening Angle bracket with two point fastening Cable clamp MS-21919 C. Cushion clamp at bulkhead hole with MS-21266 grommet Figure 9-139.  Clamping at a bulkhead hole.  Figure 9-140.  Flexible conduit. Conduit problems can be avoided by following these  guidelines: Damaged conduit sections should be repaired to preclude  injury to the wires or wire bundle that may consume as much  as 80 percent of the tube area. Minimum acceptable tube bend  Rigid Conduit •  Do not locate conduit where passengers or maintenance  personnel might use it as a handhold or footstep. •  Provide drain holes at the lowest point in a conduit  run. Drilling burrs should be carefully removed. •  Support conduit to prevent chafing against structure  and to avoid stressing its end fittings. 9-84