When choosing a cable tray before buying, you must immediately decide on the type of cable that will be laid in it. In doing so, experts take into account a wide range of factors from type of cable to contacting cable tray providers.
For example, highly sensitive low-current cables must be laid at a certain distance from each other due to the presence of shields. The operation of power cables is associated with heat dissipation. Its level must also be taken into account.
TYPES OF CABLE TRAYS
The modern market of cable support systems offers a wide variety of solutions for different types of cable products and laying (protection) conditions. In order not to get confused, familiarize yourself with the main types of cable trays and their purpose. They differ in design and permissible weight loads.
- The most versatile. Suitable for laying all types of cable - from low current to power. Moreover, in different environmental conditions.
- Designed for laying cable products with low weight: telecommunications, telephone, for control systems. Such trays can also be mounted in building ceilings and raised floors.
- Specialization - laying power cable lines with a large cross section. The cable is fixed on the crossbars of the trays with clips. This type of tray is characterized by resistance to high loads and good ventilation.
- For large distances between supporting structures. They are used to organize long cable routes if the distance between the reference points exceeds three meters. Trays can be sheet and ladder construction.
- These are whole complexes of special purpose for use in different conditions. They can be combined for individual tasks in complex projects.
- Miniature trays of a universal type for private lighting systems, "low voltage" and power wiring in small objects.
WHAT IS IMPORTANT TO CONSIDER BEFORE BUYING A CABLE TRAY?
One of the main conditions for choosing the right tray is the calculation of the required amount of space with the prospect of further filling with new cable lines. For example, if the lighting or electrification system will expand.
The volume is calculated from the diameter using the formula (2r)², where r is the bending radius of the cable.
The formula takes into account not only the volume that the cable lines themselves occupy, but also the space between them. The useful cross section will compensate for the gaps between the cables in actual laying conditions.
When calculating the volume that a cable line will occupy in a tray, a number of other factors should be considered:
- Height (the wire must not protrude above the side of the tray).
- Volume of free space (not less than 30% of the total volume of the tray, it may be required for laying additional cable lines).
- Bending radius of cable lines (at the bend and branches, the cable occupies more space, like the tray itself).
- Conditions for joint laying of cables of different types (you need to take into account the required distance between cables with different voltages and separate them with partitions).
5.Weight of the cable bundle (loading parameters of the trays and limit values can be found in the manufacturer's instructions or calculated using a special formula DIN VDE 0639).
Before contacting cable tray providers, you need to consider the relationship between its width, the height of the sidewalls and the useful cross section of the cable tray.
It should be remembered that different requirements are put forward for laying telecommunication and power cables of the same volume. For the construction of telecommunication lines, narrow and high trays are more suitable. For power - on the contrary, wide and flat.
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