The current carrying capability of the cable, the amount of voltage drop, & the length of the cable run are some of the factors that need to be taken into account when determining the optimal cable size for a given load. The following is an overview of the fundamental steps to be taken:
1). Determining current carrying capacity
2). Calculate the load current
3). Determine the current used by the load
4). Determine the voltage drop
5). Determine the size of the cable
6). Verify the following other factors
7). Check with the local codes & regulations
1). Determining current carrying capacity
The current flow that the cable can safely carry without overheating is used to assess the current carrying capacity of the cable. Typically, the manufacturer will specify this, and it will be outlined in the datasheets that they provide.
2). Calculate the load current
Calculate the current carrying capability of a cable by using cable size charts (or) online cable sizing calculators.
3). Determine the current used by the load
Find out how much current the load will be able to draw at its peak. Typically, this information will be listed either on the nameplate of the equipment or in the manual that accompanies the device.
4). Determine the voltage drop
The voltage drop is the reduction in voltage that occurs throughout the length of the cable as a result of the cable’s resistance. In order to guarantee that the equipment will function correctly, it is essential that the voltage drop remain below a certain threshold, which is generally 3%. You may calculate the voltage drop by taking into account the cable length, the current, and the cable size with the help of a voltage drop calculator.
5). Determine the size of the cable
Determine the size of the cable that can safely carry the load current while maintaining a voltage drop that is below the limit that has been stated. Copper (Cu) and aluminium (Al) cables have varying current carrying capabilities for a particular size; thus, you need to be sure that you use the right values for the material that you are working with.
6). Verify the following other factors
Because of the potential impact that other aspects, such as ambient temperature, installation technique, and cable bundling, might have on the cable’s current carrying capability, these aspects should not be ignored. If you need direction about these aspects, I recommend consulting the manufacturer’s instructions or an experienced electrician.
7). Check with the local codes & regulations
As a last step, you should make it a point to check that the cable size you’ve chosen satisfies the standards set out by the local codes & regulations.
It is possible that local codes may in certain instances impose bigger cable diameters than those that are necessary for reasons of safety.