**Voltage Drop Calculation Excel Tool**

**What is Voltage Drop?**

When electricity runs across wires, some energy is lost due to resistance in the conductors. This is referred to as voltage drop.

**i.e.,** The voltage differential between the source & load. If the voltage drop is too high, the devices connected to the circuit may not function properly.

**Formula of Voltage Drop**

**V _{D} = (LÃ—AÃ—V_{c})/1000**

is employed in electrical circuit voltage drop (VD) calculations.

Here’s the terms represent:

V_{D} – Voltage Drop (in volts)

L – Length of the conductor (in meters or feet) depending on the system used.

A – Current flows through the conductor (in A)

V_{c} – Voltage drop per unit length for the conductorÂ

The voltage drop is a measurement of the voltage loss that occurs as current flows through a wire owing to resistance.

This formula estimates the amount of voltage lost between two points in a circuit.

**Terms Purpose**

**V**_{D}** (Voltage Drop):** This is exactly what we are calculating. It’s measured in volts and indicates how much voltage is lost as current runs through the wire.

**L (Wire Length):** The distance traveled by the current through the conductor, measured in meters (or) feet. The longer the wire, it has higher resistance.

**A (Current in Amps):** The amount of electrical current passing through the cable is measured in amperes (amps).

**V**_{c}** (Voltage Drop Coefficient):** This is the voltage drop per unit length of the wire, expressed in millivolts per amp per unit length (mV/A/m for meters or mV/A/ft for feet). This value is determined by the wire’s size and material (such as copper or aluminum).

**Solved Example**

Assume you have a 50-meter-long copper wire carrying 20 amps of current and a voltage drop coefficient of 1.73 mV/A/m (typical for copper wire).

This is how the formula works.

**V**_{D}** = (LÃ—AÃ—V**_{c}**)/1000**

**V**_{D}** = (50 x 20 x 1.73)/1000**

**V**_{D}** = 1730/1000**

**V**_{D}** = 1.73 V**

So in this case, the voltage drop is 1.73 volts.

If you’re using a 120V system, this means that when the power reaches the end of the wire, it will be 120V – 1.73V = 118.27 V.

**Why Is Voltage Drop Important?**

If the voltage drop is too high, devices may not function properly because they do not receive enough power. Motors, for example, may operate at a slower speed or lights may dim.

This is the reason it is so important to consider voltage drop, particularly in lengthy cable runs.

**Tips to Reduce Voltage Drop**

- To minimize voltage drop, use shorter cables whenever practical.
- To reduce resistance, increase the wire diameter (lower gauge).
- Choose copper, which has lower resistance than aluminum.
- Limiting the current keeps the voltage drop under control.

**Click here for more**Â **Electrical Calculators**