What are cable trays?

What are cable trays?

They are mechanical support systems that provide a rigid structural system for electrical cables, conduction channels, and insulated conductors used for electrical power distribution, control, signal instrumentation, and communication. Metal cable trays are made of galvanized steel, stainless steel, and aluminum. Non-metallic cable trays are made of fiberglass reinforced plastic.

The fundamental application of the Cable Trays is to be able to carry power cables, for motive power, for lighting, command cables, data cables, alarm cables, etc. Although electrical and other types of pipes can also be mounted. Also, an adequate choice of the support means of the Cable Trays can be used for the assembly of electrical pipes or other services. It is useful that we begin by distinguishing the different types of Cable Trays recognized by the RAEA and their differentiation.

The RAEA considers different types of floor or bottom, which is the place where the cables rest. Thus we find:

  • Of wire.
  • Stair type.
  • Perforated Background.
  • solid background.

Cable trays are defined in the international electrotechnical vocabulary (Standard IEC 60050, Section 826) as:

Tray (for cables):

They are used for a cable support made up of a continuous base and raised and uncovered sides. A cable tray can be perforated or meshed (“cable tray” according to VEI 826-15-08).

Ladder tray (for cables):

They are a cable support made up of a series of transversal support elements (steps) rigidly fixed to main longitudinal support elements (“cable ladder” according to VEI 826-15-09). Similar definitions can be found in IEC 61537 “Cable tray systems and cable ladder systems for cable management”.

cable trays

To establish the admissible current of the cables that rest on them, the RAEA establishes the following distinction between the different construction types:

a) Ladder Type Cable Tray

When the surface occupied by the support steps at the bottom of the same is less than 10% of the surface of the bottom of the tray. The steps or crossbars must be distributed symmetrically and equidistant from one another. SIESA Cable Trays perfectly meet this requirement.

b) Non-perforated or solid bottom cable tray

When its bottom has a perforated surface less than or equal to 30% of the surface of the bottom of the tray.

c) Perforated Bottom Cable Tray

When its bottom has a perforated surface (with symmetrically distributed holes) greater than 30% of the surface of the bottom of the tray.

If they do not comply with this last guideline (bullet c), from the electrical point of view they should be considered as having a solid bottom with a lower use of the permissible current of the cables laid on them due to their lower transport capacity due to lower dissipation. what are you offering.

Cable trays are essential to a building's electrical system, supporting cables in the same way that highway bridges support traffic. They provide versatility and offer savings of up to 84 percent in labor costs.

 

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