Cable Voltage Drop Calculator

Calculate voltage drop in electrical cables for DC, single-phase AC, and three-phase AC circuits. Analyze power losses and determine proper wire sizing for electrical installations.

Cable Voltage Drop Analysis

Supply Voltage
Vsupply
Rcable
Vdrop
Length
Load Voltage
Vload
DC/Single Phase: Vdrop = 2 ร— I ร— R ร— L
Three Phase: Vdrop = โˆš3 ร— I ร— R ร— L
% Drop = (Vdrop / Vsupply) ร— 100

Circuit Type

Circuit Parameters

V
A
ft

Cable Specifications

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โšก Cable Voltage Drop Calculator โ€“ Accurate Wire Sizing & Power Efficiency Tool

When running electrical cables over long distances, voltage loss becomes a critical factor. As current travels through a cable, some voltage is lost due to the resistance of the conductor, resulting in a voltage drop. If this drop is too high, it can lead to inefficient operation, equipment damage, or even safety hazards.

Our Cable Voltage Drop Calculator helps you easily determine the voltage drop, voltage at the load, and whether your cable size is adequate for your application. It's ideal for electricians, engineers, solar installers, and DIY enthusiasts who want accurate and fast results.

๐Ÿง  What Is Cable Voltage Drop?

Cable voltage drop refers to the reduction in voltage that occurs when electrical current flows through a cable due to its resistance.

This drop depends on several factors:

  • โšก Current (Amperes) โ€“ Higher current causes more voltage drop.
  • ๐Ÿ“ Cable length โ€“ Longer cables result in more resistance.
  • ๐Ÿงต Cable material โ€“ Copper has lower resistance than aluminum.
  • ๐Ÿ“ Cable cross-sectional area (CSA) โ€“ Thicker cables have lower resistance.
  • ๐Ÿ”Œ System voltage and type (single-phase or three-phase).

If the voltage drop is too high, connected devices may not receive the correct voltage, leading to malfunction, overheating, or reduced lifespan.

๐Ÿ“ Cable Voltage Drop Formula

For single-phase circuits, the basic formula is:

๐‘‰drop = 2 ร— ๐ฟ ร— ๐ผ ร— ๐‘…c / 1000

For three-phase circuits, the formula becomes:

๐‘‰drop(3ฯ†) = โˆš3 ร— ๐ฟ ร— ๐ผ ร— ๐‘…c / 1000

Where:

  • ๐‘‰drop = Voltage Drop (Volts)
  • ๐ฟ = Cable Length (meters)
  • ๐ผ = Current (Amperes)
  • ๐‘…c = Cable resistance per meter (Ohms/m)

The factor of 2 in single-phase accounts for the outgoing and return path.

The voltage at the load is then:

๐‘‰load = ๐‘‰supply โˆ’ ๐‘‰drop

โš™๏ธ How to Use the Cable Voltage Drop Calculator

Our Cable Voltage Drop Calculator simplifies these calculations by letting you input the required values and instantly get the result. Here's how to use it:

  1. Select your system type โ€“ Single-phase or Three-phase.
  2. Enter the cable length (one-way distance).
  3. Enter the current flowing through the cable.
  4. Select the cable size and material (copper or aluminum).
  5. Enter the supply voltage.
  6. Click "Calculate".

You'll instantly see:

  • Total Voltage Drop (in volts)
  • Voltage Drop Percentage
  • Voltage at the Load

This allows you to adjust wire sizes or reduce distance to minimize voltage loss.

๐Ÿก Real-Life Example

Let's say you are running a single-phase 230V circuit to a workshop 80 meters away. The circuit draws 20A, and you're using copper cable with a resistance of 0.018 ohms per meter.

Calculation:
๐‘‰drop = 2 ร— 80 ร— 20 ร— 0.018 / 1000 = 5.76 V

Voltage drop percentage:
(5.76 / 230) ร— 100 โ‰ˆ 2.5%

โœ… Result: This is within the 3% limit for most installations, so the selected cable size is acceptable. If the voltage drop were higher, you could select a larger cable size to reduce resistance.

๐Ÿ’ก Why Use the Cable Voltage Drop Calculator?

Manual cable calculations can be confusing, especially when considering wire material, cross-sectional area, and length. Our calculator makes it easy:

โœ… Instant results
โ€“ no manual math required
โœ… Supports copper & aluminum
โ€“ accurate for all cable types
โœ… Single & three-phase
โ€“ versatile for all systems
โœ… Voltage drop percentage
โ€“ check against standards

Whether you're working on a home wiring project, a commercial installation, or a solar energy system, this tool ensures you meet voltage drop standards and avoid costly mistakes.

โ“ Frequently Asked Questions (FAQs)

1. What is the maximum allowed cable voltage drop?

A: Most regulations recommend a maximum voltage drop of 3% for lighting and 5% for power circuits to ensure proper equipment performance.

2. Which is better: copper or aluminum cable?

A: Copper has lower resistance, so it produces less voltage drop for the same cable size. However, aluminum is cheaper and lighter but may require larger cross-sectional areas to achieve the same performance.

3. Can voltage drop damage equipment?

A: Yes. Excessive voltage drop can cause motors to run hot, lights to dim, or sensitive electronics to malfunction.

4. Can this calculator be used for DC circuits?

A: Yes. For DC circuits (such as solar installations), the single-phase formula applies. Just make sure to input correct values for wire length, current, and resistance.

5. How can I reduce voltage drop in my cable installation?

A:

  • Use larger (thicker) cables
  • Keep cable runs as short as possible
  • Reduce the current draw
  • Increase the supply voltage (where safe and applicable)

๐Ÿ“ Final Thoughts

Cable voltage drop plays a critical role in the efficiency, safety, and reliability of any electrical system. Undersized cables can cause energy waste, equipment malfunction, and even fire hazards.

With our Cable Voltage Drop Calculator, you can quickly check if your chosen cable is suitable, adjust wire sizes, and ensure your installation meets recommended voltage drop limits.

๐Ÿ‘‰ Try it now and design your circuits the right way: Use the Cable Voltage Drop Calculator on voltagecalculator.online