Step-by-Step instructions for selecting the appropriate electrical cable:
Step: 1). Data Gathering
Step: 2). Current Rating
Step: 3). Calculate Voltage Drop
Step: 4). Short Circuit Temperatures Rise
Step: 5). Earth Fault Loop Impedance
Step: 6). Final Selection
Step: 1). Data Gathering
Load Details: Identify the type & quantity of load that the cable will support.
Cable Construction: Determine the type of cable required (e.g., single or multi-core).
Consider where & how the wire will be put (underground, in conduit, or exposed).
Step: 2). Current Rating
Base Current Ratings: Determine the cable’s current carrying capacity.
Installed Current Ratings: Adjust for the installation variables such as ambient temperature and cable grouping.
Step: 3). Calculate Voltage Drop
Cable Impedances: Calculate the impedance of the cable.
Calculating Voltage Drop: Ensure that the voltage drop is within acceptable ranges.
Maximum Cable Length: Calculate the maximum length of cable based on voltage drop calculations.
Step: 4). Short Circuit Temperatures Rise
Minimum Cable Size: Make sure the cable can survive short-circuit circumstances.
Temperature Considerations: Take into account the temperatures of the initial and final conductors during a short circuit.
Step: 5). Earth Fault Loop Impedance
Earth Fault Loop: Calculate the impedance of the earth fault loop to verify that protective devices operate properly.
Maximum Cable Length: Determined using the earth fault loop impedance.
Step: 6). Final Selection
Highest Size: Determine the cable size based on highest need from the preceding phases.
Ensure that the cable you select meets all applicable standards and regulations, such as IS 694 (Indian Standard for PVC Insulated Cables), IEC 60502 (International Standard for Power Cables), or other region-specific requirements. Compliance ensures safety, dependability, and performance in electrical installations.
You can also follow us on AutomationForum.co, Facebook and Linkedin to receive daily Instrumentation updates.
You can also follow us on ForumElectrical.com , Facebook and Linkedin to receive daily Electrical updates.