Enter the current and voltage into the calculator to determine the feeder size. This calculator helps in sizing electrical feeders based on the electrical load and voltage.
Feeder Size Formula
The following formula is used to calculate the feeder size.
FS = (2 * ρ * I) / (V * PF)
Variables:
- FS is the feeder size (circular mils)
- ρ is the resistivity of the conductor material (ohms per circular mil foot)
- I is the current (amperes)
- V is the voltage (volts)
- PF is the power factor (dimensionless), typically assumed to be 1 for simplicity
To calculate the feeder size, multiply the resistivity of the conductor material by the current, then multiply by 2, and divide by the product of the voltage and the power factor.
What is Feeder Size?
Feeder size refers to the cross-sectional area of an electrical feeder wire, which is necessary to carry a certain amount of current without overheating or dropping too much voltage. It is typically measured in circular mils, which is a unit of area used specifically for wires. Proper feeder sizing is crucial for the safety and efficiency of an electrical system.
How to Calculate Feeder Size?
The following steps outline how to calculate the Feeder Size.
- First, determine the current (I) in amperes.
- Next, determine the voltage (V) in volts.
- Next, gather the formula from above = FS = (2 * ρ * I) / (V * PF).
- Finally, calculate the Feeder Size (FS) in circular mils.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
current (I) = 100 amperes
voltage (V) = 240 volts
