Clear and Concise Guide to Power Cable Sizing
Clear and Concise Guide to Power Cable Sizing
This is a cable sizing table. It shows the recommended sizes of cables for different current ratings and installation methods. Here’s a breakdown of the information in the table:
- Current Rating of MCBS/MCCBS (AF Rating): This column shows the amperage rating of the Miniature Circuit Breakers (MCBs) or Moulded Case Circuit Breakers (MCCBs) that the cables are designed to be used with.
- PVC, XLPE/PVC Cables FR Cables: These columns show the recommended cable sizes for PVC, XLPE/PVC, and FR (fire-resistant) cables for each current rating and installation method.
- Installation Method: This column shows the recommended installation method for each cable size. The options include cables in trunking/conduit, cables in trunking/cable tray, and cables in cable tray/cable ladder.
For example, the table shows that a 20A MCB for cables in trunking/conduit should be used with either two 4 sqmm 1C PVC cables or two 4 sqmm 1C FR cables.
It is important to note that this table is for informational purposes only and should not be used as a substitute for professional advice from a qualified electrician. The correct cable size for a particular application will depend on a number of factors, such as the length of the cable run, the voltage drop, and the ambient temperature.
Here are some additional observations about the image:
- The table is applicable for cable runs of up to 100 meters. For longer cable runs, the next larger cable size should be used.
- The table does not take into account voltage drop. It is important to calculate the voltage drop for your specific application to ensure that the cable size you choose is adequate.
- The table does not take into account ambient temperature. If the cables will be installed in a hot environment, you will need to choose a larger cable size to prevent overheating.