FEC MICRO NR - Manual (Page 51)

FEC Micro NR Operations Manual Chapter 4: System Setup and Wiring (Rev2.1: 12/12)
Page 4-17
4.7.2 Considerations for Cable Trolleys

Cables hung by festooning type systems must be secured to the individual cable trolley and
positioned to avoid sharp bends and eliminate or minimize any torsion twisting.

Restraint cords should be used in between cable trolleys to limit movement and reduce the
stress on cables as they are extended. Restraint cord lengths must always be shorter than the
length of cable hung between trolleys.

Cable loops should be consistent in length,typically not exceeding 5 feet in depth between
trolleys. Sufficient number of trolleys should be used in a system to support the entire length of
moving cable and to allow relaxed stacking/festooning of cable loops when tool is in the
retracted position.

One trolley should be fixed to the runway rail to eliminate tugging on or stretching of cables.
4.7.3 Considerations for Flexible Cable Tracks

Cables must under no circumstances have the opportunity to tangle. Therefore the
clearance height of a track compartment with several similar cables next to one another must
not amount to more than one and a half times the cable diameter.
 There should be an “all around” minimum clearance between cables of 10% of the cable’s
diameter.

Cables and hoses with very different diameters should be laid separately. Separation is
achieved by using Flexible Track separators. The following rules should be followed for cable
separation:
o If (Cable 1 Diameter) + (Cable 2 Diameter) > 1.2 x Track Inner Height, then no
separation is necessary.
o If (Cable 1 Diameter) + (Cable 2 Diameter) ≤ 1.2 x Track Inner Height, then a
horizontal or vertical separator must be used to reduce the inner height, thereby
preventing the entanglement of the cables.

The cable weight should be symmetrically distributed along the width of the track.

Cables must be able to move freely along the radius.

The cables must be secured with strain relief at both ends. In exceptional cases, the cables
may be fixed with strain relief at the moving end only. Unless using a Flexible Cable Track with
integrated strain relief, a gap of 10~30 x cable diameter between the end of the bending
segment and the fixed point is recommended for most cables.

Under no circumstances should excess cable be put into a Flexible Cable Track.
4.7.4 Considerations for Cable Trays & Ladders

Cable drop out panels should be used where cables enter and exit a tray or ladder system.
Sharp bends need to be avoided whenever possible.

Cables should be secured at both entry and exit points of a tray or ladder.

Avoid running high voltage or high frequency cables in the same tray or ladder as signal or
control cables unless cables are designed for such environments.

If excess cable is to be stored in a tray or ladder, do not tightly coil cable. Cable should be laid
in as large of a loop as possible.