Cable tray is a bridge that allows safe transport of wires across open spans and give protection against the overheating and fire buildup problems.
Types of Cable Trays – Purpose, Advantages,
Disadvantages
Cable tray systems are
alternatives to wire ways and electrical conduit, which completely enclose
cables.
Cable
trays are capable of supporting all types of wiring: such as
- High Voltage Power
Lines.
- Power Distribution
Cables
- Control cables
- Telecommunication cables
- Fiber Optical Cables
Purpose:
Cable
trays are components of support systems for power and communications cables and
wires.
A cable
tray system supports and protects both power and signal cables and facilitates
upgrading, expanding, reconfiguring, or relocating networks.
Most of
the cable tray systems are open, allowing efficient heat dissipation and easy
access for replacement and repairs. Although typically suspended from ceilings
or affixed to walls, some cable tray systems are suitable for under floor use.
Types of Cable Trays:
The
following are popular cable tray types.
- Ladder-type
- Perforated type
- Solid bottom type
- Wire mesh
- Channel type
An
engineer or designer will usually specify the type of cable tray that has the
features to suit the project. It depends on the situation and the environment.
The
selection of cable tray depends upon the number of cables, size, spacing, and
weight of cable in the tray.
Ladder Cable Tray
Ladder Cable tray has two side rails connected by rungs.
This type of cable tray is effective because the ladder rungs give you easy
accessibility to the cables, from the top or bottom.
The rungs
of the ladder cable trays provide convenient anchors for tying down the cables
in the non-horizontal cable tray runs or where the positions of the cables must
be maintained in the horizontal cable tray runs.
Perforated Cable Tray
Perforated cable tray
Consists of a ventilated
bottom with side rails. It provides more support to cables than the
ladder-type,
Solid-bottom Cable Tray
Solid-bottom Cable
trays for fiber-optic
cable installations where drooping of cables may affect system performance,
solid-bottom (non-ventilated) cable trays are preferred.
However,
the main reason for selecting solid-bottom trays is a concern for
electromagnetic/ radio-frequency interference protection.
Wire mesh
cable tray
Wire mesh cable tray, also called basket
cable tray, is a kind of
cable tray made of stainless steel wires by welding wires together, forming a
basket-like mesh
Cable
Trays are mainly used for low voltage, telecommunication, and fiber optic
cables supported on short spans.
Channel Cable Tray
Channel cable tray nothing more than a metal tray that can be
used for very small cable installations.”
Materials
1. Metallic
Aluminum: Resists corrosion; excellent
strength-to-weight ratio. Aluminum is most commonly used because it is
lightweight.
Steel: Electric shielding; low thermal expansion
Stainless steel: Superior corrosion resistance; withstands
high temperatures.
2.Non-Metallic
Fiberglass: Nonconductive; resists corrosion;
lightweight
Precautions:
The most
important issue is to ensure that the bend radius for the fiber-optic or
coaxial cable is maintained within the standards.
Combustible
dust and clutter may accumulate if the trays are not routinely checked and kept
clean.
Advantages:
Less expensive: One of the big advantages that using a
cable tray has that it costs a lot less than other methods of protecting wiring
on the production floor.
Maintenance: Cable are instantly visible for
maintenance checks, changing of cables is easy because cables can enter or exit
the tray at any point of the system.
Safety: Regular housekeeping is important for
safety, as cable trays are often installed in hard to reach places.
Disadvantages:
The solid
bottom cable tray system has a disadvantage. In that moisture can build up in
the cable trays.
SPACE
FACTOR OF CABLE TRAY SYSTEM
A maximum
space factor of cable tray is 20%
Size
of cable tray
Thickness available 1.6mm,2.0mm,2.5mm,3.0mm.
Standard depths of 25,40,50,75,100mm. Standard lengths of 2.5/3.0 Mtrs.