Voltage Drop Calculator

The free voltage drop calculator is intended to help you in determining the voltage drop across a wire piece. Based on the data from NEC and Wire Resistance terminology, this volt drop calculator DC will show you various parameters that will be good to know while installing energy lines for residential or commercial purposes.

Now it’s time to move by and discuss the voltage loss calculation concept in proper detail.

Let’s get down to the topic!

What Is Voltage Drop?

In the field of electrical energy transmission:

“The overall loss of the voltage due to the internal impedance of the circuit is known as the voltage drop”

Pictorial Representation:

In the above figure, we have a voltage applied to a circuit network containing only a resistance. Now when the current will pass through the resistance, there will be a drop in voltage from one end to the other end of the resistor. This drop is actually the voltage drop that could be instantly determined by using this voltage calculator.

Example:

Just make a supposition about the water pipe having a hose at its one end. The reason why we are considering it here is its best match to the voltage drop terminology. Here:

• Water that flows out of the hose is equivalent to the current flowing through a wire
• The resistance caused by the conductor is almost equal to that of the opposition caused by the size of the water pipe

Here this best wire voltage drop calculator is the best method that assists you to determine the voltage drop across any conductor, no matter how sharp the opposition is!

Types of Voltage Drop:

According to the IEEE(Institute of Electrical and Electronics Engineers), there are basically a couple of kinds of voltage drop. It is mainly due to the direction of the current flowing through an electrical circuit. Let’s discuss them one by one!

Positive Voltage Drop:

Positive drop in the voltage occurs when the electronic current flows through the circuit.

Electronic Current:

The current from the negative terminal of the circuit to its positive terminal is termed electronic current.

Cause:

• Electrons in a conductor

Negative Voltage Drop:

This voltage drop usually occurs in a circuit when there is conventional current flowing through it.

Conventional Current:

This specific current is flown from an area of high potential to the area of low potential in an electric circuit.

Cause:

• Holes in a conductor

Voltage Drop Equations:

For AC and DC voltages, we have different formulas depending upon the phase system that is in use. You must be capable of determining the drops across the voltages and other electricity related parameters. And for this purpose, you must have a sound grip over the following expressions:

Voltage Drop Formula for Single Phase:

$$ V_{drop\left(V\right)} = I_{wire\left(A\right)} * R_{wire\left(Ω\right)} $$

$$ V_{drop\left(V\right)} = I_{wire\left(A\right)} * \left(2 * L_{\left(ft\right)} * \frac{R_{wire\left(\frac{Ω}{kft}\right)}}{1000_{\left(\frac{ft}{kft}\right)}}\right) $$

$$ V_{drop\left(V\right)} = I_{wire\left(A\right)} * R_{wire\left(Ω\right)} $$

$$ V_{drop\left(V\right)} = I_{wire\left(A\right)} * \left(2 * L_{\left(m\right)} * \frac{R_{wire\left(\frac{Ω}{km}\right)}}{1000_{\left(\frac{m}{km}\right)}}\right) $$

Voltage Drop Formula for Three Phase:

$$ V_{drop\left(V\right)} = \sqrt{3} * I_{wire\left(A\right)} * R_{wire\left(Ω\right)} $$

$$ V_{drop\left(V\right)} = 1.732 * I_{wire\left(A\right)} * \left(L_{\left(ft\right)} * \frac{R_{wire\left(\frac{Ω}{kft}\right)}}{1000_{\left(\frac{ft}{kft}\right)}}\right) $$

$$ V_{drop\left(V\right)} = \sqrt{3} * I_{wire\left(A\right)} * R_{wire\left(Ω\right)} $$

$$ V_{drop\left(V\right)} = 1.732 * I_{wire\left(A\right)} * \left(L_{\left(m\right)} * \frac{R_{wire\left(\frac{Ω}{km}\right)}}{1000_{\left(\frac{m}{km}\right)}}\right) $$

Whatever the phase is, our free voltage drop calculator will take a couple of seconds to display the actual loss in the voltage transmission.

Diameter of the Wire:

For a wire having a diameter in inches and n gauges:

$$ d_{n\left(in\right)} = 0.005 inches * 92^{\frac{\left(36-n\right)}{39}} $$

And when the diameter is in millimetres:

$$ d_{n\left(mm\right)} = 0.127 mm * 92^{\frac{\left(36-n\right)}{39}} $$

Cross Section Area of Wire:

$$ A_{n\left(kcmil\right)} = 1000 * d_{n}^{2} = 0.025 in^{2} * 92^{\frac{\left(36-n\right)}{19.5}} $$

$$ A_{n\left(in^{2}\right)} = \left(\frac{\pi}{4}\right) * d_{n}^{2} = 0.000019635 in^{2} * 92^{\frac{\left(36-n\right)}{19.5}} $$

$$ A_{n\left(mm^{2}\right)} = \left(\frac{\pi}{4}\right) * d_{n}^{2} = 0.000019635 mm^{2} * 92^{\frac{\left(36-n\right)}{19.5}} $$

Resistance By The Wire:

$$ R_{n\left(\frac{Ω}{kft}\right)} = 0.3048 * 10^{9} * \frac{ρ\left(Ω.m\right)}{25.4^{2} * A_{n\left(in^{2}\right)}} $$

Causes of Voltage Drop:

There can be many causes of the voltage drop. But most highlighted of them are enclosed in this section. So let’s give a read!

Conductor’s Material Choice:

This is indeed the most important factor that helps you to avoid any voltage issues within your residential or commercial supply. Many conductive materials are there in use but the best and affordable among them include copper and iron. Among these two, copper is more reliable because its voltage drop drop capacity is less than the iron. Furthermore, you can also verify the fact by using this best voltage drop calculator. Below we have a table that throws a light on significant properties of different conductive materials that are being used in the market:

Size of Wire:

Length and diameter are two factors that contribute to the voltage drop. Here the most remarkable fact to consider is that the wire having large lengths will have low drop in voltage when compared to the wires of smaller lengths.

American Wire Gauge Sizes:

AWG System is specifically developed by American Electrical Industry and it helps you to estimate the diameters of the round conductor wires of various lengths and sizes. The following table contains the standard diameters of the wires most widely used by consumers:

Current Capacity In the Wire:

The amount of electrons flowing through a wire is directly proportional to the voltage drop occurring in it. This current capacity, when it reaches its peak, is referred to as the ampacity of the conductor. You can use a free voltage calculator to check how maximum amperes will affect the voltage being transmitted.The electricity cost can be controlled by measuring the overall voltage and the total appliances installation in your apartment. The electricity cost calculator can be handy in regulating your electric cost per month.

Voltage Drop Chart:

Below here we have a proper tables that provide a whole concept of the voltage changes depending upon the length of the wires. Let’s have a look at these!

Voltage Supply 120 Volts:

Voltage Supply 240 Volts:

You can also verify all these values by subjecting to our free dc voltage drop calculator.

How To Calculate Voltage Drop?

Let’s resolve an example to clear your mind about the voltage drop. Just stay focused!

Example Problem:

How to calculate voltage drop in a series circuit having ampacity of 56 amps and opposition to it as 43 ohms?

Solution:

Using voltage drop calculation formula:

$$ V_{drop\left(V\right)} = I_{wire\left(A\right)} * R_{wire\left(Ω\right)} $$

$$ V_{drop\left(V\right)} = 56 * 43 $$

$$ V_{drop\left(V\right)} = 2.4 V $$ (For calculations, tap Ohm’s Law Calculator)

How Voltage Drop Calculator Works?

Get going through the usage guide of this voltage loss calculator that will let you observe various electrical elements in a couple of clicks.

Input:

• From the first drop-down list, select whether you want to do calculations on the basis of “Estimated Voltage”, “NEC Data”, or any “Other Parameters”

If you selected the “Estimated Voltage”:

• Select the wire material from next drop-down list
• Fill all the required fields with appropriate values been given to you
• At last, tap the calculate button

If you selected the “NEC Data”:

• Select from the next list what you are interested in to measure:
• Write the parameters in their designated spaces
• Hit the calculate button

If you selected the “Other Parameters”:

• Go for putting all the sked values in proper fields and tap the calculate button

Output:

The free voltage calculator does the following calculations in seconds:

• Voltage Drop
• Percentage of Voltage Drop
• Wire Resistance
• Voltage At The End
• Maximum Conductor Length
• Conductor Cross-sectional Area
• Voltage at Max Drop

FAQ’s:

What causes a voltage drop?

When the potential at the final end of the wire gets higher than the potential at the start, then it gives rise to the voltage drop that could be judged with this voltage drop calculator.

Does voltage drop over distance?

When you are interested in transmitting the voltage over long distances, then the length of the wire would be enhanced. This increase will be directly proportional to the resistance and when the resiste\ance increases, the voltage drop will also get maximum. That is why very long voltage transmission losses more voltage. This fact can also be analysed by a volt drop calculator.

How do you prevent voltage drop?

Following are the precautions that you can take in order to minimise the voltage drop in a line. Theses include:

• Temperature of the conductor must be reduced enough
• Length of the conductor should be decreased
• Reduce the power load connected to the circuit
• Increasing the number of the conductors connected in circuit

The overall decrease in the final voltage can also be calculated by this voltage calculator.

What is the difference between voltage and voltage drop?

The voltage across the conductive material is the actual voltage flowing through it. While on the other hand, the voltage drop is the voltage that is provided by any external device or electrical circuit connected.

What happens to current when voltage drops?

If we recall Ohm’s law and keep the resistance of the linear circuit as fixed, then a reasonable increase in the voltage will also increase the overall current and vice versa.

How much voltage drop is acceptable?

The maximum voltage loss calculation that could be tolerable between a feeder conductor to the farthest load connected in series or parallel must not exceed the value of the 5%.

Why does voltage drop under load?

When a battery is connected to a load of certain power, voltage drop occurs in it. This is due to the chemical reactions taking place in the battery that produces the electricity. When the current gets increased more and more, the flow of electrons from one electrode of the battery to the other also gets increased.

Are potential drops and voltage drops the same?

Potential drops are caused in the presence of the ground. But voltage drops are the drop caused by the current facing some amount of reasonable resistance. You can also measure this drop in any circuit network with this wiring voltage drop calculator.

What happens if voltage is too low?

When the voltage gets too low, the amperage increases enough to melt down the electrical conductors. This causes abnormality in the functioning of the load devices.

Is 2% voltage drop acceptable?

According to the solar industry lexicon, the voltage drop must be controlled so as it could not increase the 2% at its maximum. This behaviour can be checked by this voltage calculator in a fragment of seconds.

What is the maximum voltage drop in a domestic property?

For a single phase line, the maximum drop that is acceptable is around 230.4V. While in case of a three phase system, the drop at its minimum must be 398.4V.

What is a voltage drop test?

This particular test can be used to diagnose problems that are caused in a circuit due to the high resistances. And you can perform the voltage drop test by either of the two ways below:

• Using a Digital Multimeter (DMM)
• Using this voltage drop calculator wire size (The best method considered so far)

Is AC and DC wire the same?

No. Both are different. Where the alternating cables are insulated using a single coating, the direct current cables are insulated by employing double insulation.

Why is gold not used in electrical wiring?

No doubt gild is also a good conductor of electricity but it is not used due to being very expensive. Contrary to it, copper, aluminium, and iron are very cheap and effective conductors of both electricity and current.

Why is DC not used in homes?

Direct current is not used in homes because its value never becomes zero. This is very lethal as when a person accidentally touches a live wire or there is any short circuit in circuit, the voltage will not be changed and it will destroy the component or may let the person die.

References:

From the source of Wikipedia: Voltage drop, Voltage drop in direct-current circuits, Voltage drop in alternating-current circuits

From the source of Khan Academy: Kirchhoff’s laws, Currents into a node, Resistivity and conductivity, Voltmeters and Ammeters, Electrolytic conductivity

From the source of Lumen Learning: Ohm’s Law, Resistance and Simple Circuits, Conservation of Energy