The cable tray size is described in two dimensions: width and height. Calculating the size of a cable tray means calculating its width.

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The final size of a cable tray depends on the following:

1- The number of cables on the cable tray

2- The size and overall diameter of each cable

3- The future expansion

The general rule for sizing the cable tray is that all the cables must be installed in a single layer, and there must be a space between each two cables:

1- The space between two multi core cables equals the diameter of bigger cable.

2- The space between three single core cables in trefoil formation and other trefoil cables equals the double of the diameter of the bigger cable.

Then, we measure the overall width of the previous arrangement to find the initial cable tray width, then add the future expansion.

Final cable tray width= initial cable tray width*(1+expantion percentage)

We round the final cable width to the nearest biggest standard width, which equals 50, 100, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900 mm (Can be different according to the manufacturer).

Example:

Find the cable tray size which will carry the following cables. Consider future expansion = 20%.

4x25mm2 CU/XLPE/PVC cable, diameter= 22.0 mm

4x120mm2 CU/XLPE/PVC cable, diameter= 39.9 mm

4x35mm2 CU/XLPE/PVC cable, diameter= 25.4 mm

4x50mm2 CU/XLPE/PVC cable, diameter= 28.3 mm

4x70mm2 CU/XLPE/PVC cable, diameter= 32.1 mm

Initial cable tray size= 310 mm

Final cable tray size= 310*1.2= 372 mm

We round this value to the nearest bigger cable tray standard value = 400 mm

Example:

Find the cable tray which will carry the following cables. Consider future expansion = 20%.

4No. of 3(1x240) mm2 CU/XLPE/PVC cable, diameter= 31.9

Initial cable tray size= 510 mm

Final cable tray size= 510 x 1.2= 612 mm

We round this value to the nearest bigger cable tray standard value = 700 mm

What about separate neutral and earthing conductors?

Because neutral and earthing conductors normally don't carry current, we don't put these conductors into consideration when sizing cable trays. When laying, they will be laid beside the main cable.

Why do we add space between cables?

Grouping the cables without adding space on cable trays is possible, but when calculating the maximum carrying current capacity for the cables, you have to take into account the derating factor for cables when touching on the cable tray.

With reference to the tables below in BS* standard (There are similar tables in IEC** standard), we can find the derating factors for both cases; cables are touched and cables are spaced.

When the cables are touched, the derating factors range from 0.85 to 0.6 depending on the number of cables. Which means that the size of the cables could be nearly doubled. That will lead to an increase in the cost of cables.

But, if we look at the rating factors when cables are spaced, we find that they have a range between 1 and 0.9, which has little effect on maximum carrying current capacity.

*BS &#; Table 4C4 and Table 4C5

 **IEC -5-52 &#; Table B.52.20 and Table B.52.21

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Low voltage electrical cable&#;s designations (0.6 / 1 KV)

Each low voltage cable has a designation according to the norm. This denomination is composed by a set of letters and numbers, each with a specific meaning. This designation refers to a series of product characteristics (materials, nominal voltages, etc.) that facilitate the most suitable cable selection for your needs, avoiding possible errors in the cable supply.

When a cable does not indicate this data clearly, it may be a faulty cable, which does not meet the safety standards or its proper functioning.

INDUSTRIAL POWER LOW VOLTAGE CABLES 0.6 / 1KV

Industrial power cables  0.6 / 1kV are for industrial power applications in various fields (general industry, public facilities, infrastructures, etc.), and international standards: UNE, IEC, BS, UL.

Some low voltage power examples cables 0.6 / 1kv are the following:

• THE ACRONYM MEANINGS FOR THE COMMERCIAL CABLE&#;S NAME

What does it mean, for example, RZ1-K on a Top Cable Toxfree ZH RZ1-K cable?

After the manufacturer name (in this case, Top Cable) and the Trademark (Toxfree), the letters and numbers refer to the coatings of the cable, the conductor class, to the nominal voltage and to the composition end of the cable.

• R  is the insulation type, in both cases, is Reticulated Polyethylene (XLPE).

• Z1 indicates that this cable has a polyolefin cover not flammable, halogen-free and with low smoke emission and corrosive gases in case of fire. Its designation is Z1.
• K the letter K indicates that it is a flexible copper conductor (class 5), for fixed installations.

0.6 / 1 kV indicates that it is a -volt cable

Another example of the acronym&#;s meaning can be found with the Powerhard RVMV cable 0.6 / 1kV; which is the following:

 LOW VOLTAGE CABLE DENOMINATION 0.6 / 1kV

Each cable has a standard designation. This designation is composed of a set of letters and numbers, each with a specific meaning. This designation refers to a series of product characteristics (materials, nominal tensions, etc.) that facilitate the selection of the most suitable cable for your needs, avoiding possible errors in the supply of one cable by another.

When a cable does not clearly indicate these data, it may be a defective cable, which does not comply with safety regulations or guarantee the cable&#;s life and proper operation.

The meaning of each letter within each section is as follows:

Designation according to type of insulation

nomenclature Cable type R Crosslinked polyethylene (XLPE) X Cross-linked polyethylene (XLPE) Z1 Halogen-free thermoplastic polyolefin Z Halogen-free thermosetting elastomer V Polyvinyl chloride (PVC) S Halogen-free thermosetting silicone compound D Ethylene-propylene elastomer (EPR)

Screen designation, interior lining, armature seat

nomenclature Cable type C3 Copper wire screen, helically arranged C4 Copper shield in the form of a braid, on the assembled insulated conductors. V Polyvinyl chloride (PVC) Z1 Halogen-free thermoplastic polyolefin

If there is no screen, no inner lining and no armature seat, no letter is used.

Designation of the different types of armor

nomenclature Cable type F Steel strapping arranged in a helical pattern. FA Aluminium strapping arranged in a helical pattern FA3 Longitudinally corrugated aluminium strip M Steel wire crown MA Aluminium wire crown

Designation of the outer sheath

nomenclature Cable type V Polyvinyl chloride (PVC) Z1 Halogen-free thermoplastic polyolefin Z Halogen-free thermosetting elastomer N Vulcanized chlorinated polymer

Conductor&#;s designation

nomenclature Cable type K Flexible copper (class 5) for fixed installations F Flexible copper (class 5) for mobile services D Flexible for welding machine cables. When there are no letters on it, the conductor is made of solid copper, class 1 or 2. AL AL If the conductor is made of aluminium, (AL) is indicated.

Rated voltage

Rated voltage 0,6/1 kV Rated voltage 1,000V

Explanation of the number of conductors

nomenclature Cable type nGS Number and cross-section of wires, in mm2 , with Yellow/Green conductor nxS Number and cross-section of conductors, in mm2 , without conductor Yellow/Green

Cable design rules

The cable design rules are also referenced in the marking of each cable:

• UNE
• IEC
• UNE

Additional data

nomenclature Cable type CE CE CE marking is compulsory for the marketing of the product in the European Community. This marking can be on the product or on the packaging. Manufacture date Date of manufacture (YYMMDD). The date of manufacture is usually placed for traceability purposes. Traceability makes it possible to know who, when and where has carried out each stage of the process and with which materials.

You can review concepts through this video that we have prepared:

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