When installing air conditioners, it's essential to use the appropriate cable size to ensure safe and efficient operation. The cable size needed depends on the power consumption and the distance between the main distribution board and the air conditioner unit.
To calculate the appropriate cable size, we'll need the following information:
- Power consumption of the air conditioner in watts (W) or kilowatts (kW).
- Voltage of the electrical supply (e.g., 220V, 240V, 380V, etc.).
- The permissible voltage drop (usually 3% for most electrical installations).
Unfortunately, you provided the cooling capacity of the air conditioner in BTU (British Thermal Units), but we need the power consumption in watts or kilowatts. However, I can provide you with the general steps to calculate the cable size once you have the power consumption data.
Step 1: Determine the total power consumption of the air conditioner units in watts (or kilowatts) by consulting the manufacturer's specifications or the nameplate on the air conditioner.
Step 2: Decide on the permissible voltage drop. As mentioned earlier, a common value is 3% for most installations.
Step 3: Calculate the maximum allowable voltage drop (in volts) using the formula:
Maximum Allowable Voltage Drop = (Permissible Voltage Drop / 100) x Supply Voltage
Step 4: Estimate the total current the air conditioner will draw using the formula:
Total Current (Amps) = Total Power Consumption (Watts or kW) / Supply Voltage (Volts)
Step 5: Calculate the resistance of the cable in ohms using the formula:
Cable Resistance (ohms/m) = Maximum Allowable Voltage Drop (Volts) / Total Current (Amps) / Distance (m)
Step 6: Choose a cable size that has a resistance value per meter lower than the value obtained in Step 5. You can consult cable size charts provided by cable manufacturers or local electrical codes for this purpose.
Once you have the specific power consumption data, you can perform the above calculations to determine the appropriate cable size for your installation. If you are uncertain about performing these calculations yourself, it's best to seek the assistance of a qualified electrician or electrical engineer who can accurately determine the required cable size for your specific setup.