DC Cable Sizing Calculation Formula

DC Cable Sizing Formula:

\[ \text{Wire Area} = \frac{I \times \text{Length} \times 2 \times \text{Resistivity}}{\text{Voltage Drop}} \]

Current I (A):

Length (m):

Resistivity (Ω·m):

Ω·m

Voltage Drop (V):

Wire Area:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the DC Cable Sizing Formula?

The DC Cable Sizing Formula calculates the required cross-sectional area of a cable based on current, length, material resistivity, and acceptable voltage drop. It ensures proper electrical performance and safety in DC power systems.

2. How Does the Calculator Work?

The calculator uses the DC Cable Sizing formula:

\[ \text{Wire Area} = \frac{I \times \text{Length} \times 2 \times \text{Resistivity}}{\text{Voltage Drop}} \]

Where:

\( I \) — Current in amperes (A)
\( \text{Length} \) — Cable length in meters (m)
\( \text{Resistivity} \) — Material resistivity in ohm-meters (Ω·m)
\( \text{Voltage Drop} \) — Maximum acceptable voltage drop in volts (V)

Explanation: The formula calculates the minimum cross-sectional area required to maintain voltage drop within acceptable limits for a given current and cable length.

3. Importance of Proper Cable Sizing

Details: Proper cable sizing is crucial for electrical safety, efficiency, and performance. Undersized cables can cause excessive voltage drop, overheating, and potential fire hazards, while oversized cables are unnecessarily expensive.

4. Using the Calculator

Tips: Enter current in amperes, length in meters, material resistivity (copper is typically 1.68×10⁻⁸ Ω·m), and maximum acceptable voltage drop. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why multiply length by 2 in the formula?
A: The factor of 2 accounts for the round-trip path of current in a DC circuit (both positive and negative conductors).

Q2: What is typical resistivity for copper?
A: Copper has a resistivity of approximately 1.68×10⁻⁸ Ω·m at 20°C. This value increases with temperature.

Q3: What is an acceptable voltage drop?
A: Typically 3-5% of system voltage for power circuits, but specific applications may have different requirements.

Q4: Does this account for temperature effects?
A: No, this is a basic calculation. For precise sizing, temperature correction factors should be considered.

Q5: Can this be used for AC circuits?
A: No, AC circuits require additional considerations for skin effect and power factor. Use AC-specific formulas for AC applications.