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 Voltage Drop Calculator

Voltage Drop Calculator

The calculator will calculate the voltage drop, its percentage, and resistivity of any wire piece.

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By using

To Find

Wire Material

Wire Material

Resistivity

Max Voltage Drop

Wire Size

Wire Length

 

Wire Length

 

Enter Gauge

Wire Diameter Size

 

Load Current

 

Number of conductors

Voltage

 

Material of conduit

Power Factor (PF)

Wire resistance

 

Phase

Insulation

Installation

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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:

voltage drop
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.

positive voltage drop

Electronic Current:

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

negative voltage drop

Conventional Current:

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

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:

Electric conductivity (10.E6 Siemens/m) Electric resistivity (10.E-8 Ohms.m) Thermal conductivity (W/m.K) Thermal expansion factor 10E-6(K-1) de 0 à 100°C Density (g/cm3) Melting or deterioration temperature (°C)
Silver 62,1 1,6 420 19,1 10,5

961

Copper

58,7 1,7 386 17 8,9 1083
Gold 44,2 2,3 317 14,1 19,4

1064

Aluminium

36,9 2,7 237 23,5 2,7 660
Molybdenum 18,7 5,34 138 4,8 10,2

2623

Zinc

16,6 6,0 116 31 7,1 419
Lithium 10,8 9,3 84,7 56 0,54

181

Brass

15,9 6,3 150 20 8,5 900
Nickel 14,3 7,0 91 13,3 8,8

1455

Steel

10,1 9,9 80 12,1 7,9 1528
Palladium 9,5 10,5 72 11 12

1555

Platinium

9,3 10,8 107 9 21,4 1772
Tungsten 8,9 11,2 174 4,5 19,3

3422

Tin

8,7 11,5 67 23,5 7,3 232
Bronze 67Cu33Sn 7,4 13,5 85 17

8,8

1040

Carbone steel

5,9 16,9 54 12 7,7 1400
Carbone 5,9 16,9 129 0,2 1,8

2500

Lead

4,7 21,3 35 29 11,3 327
Titanium 2,4 41,7 21 8,9 4,5

1668

Stainless steel 316L EN1.4404

1,32 76,0 15 16,5 7,9 1535
Stainless steel 304 EN1.4301 1,37 73,0 16,3 16,5 7,9

1450

Stainless steel 310 EN1.4841

1,28 78 14,2 17 7,75 2650
Mercury 1,1 90,9 8 61 13,5

-39

FeCrAl

0,74 134 16 11,1 7,2

+-1440

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:

AWG

Diameter

Turns of wire Area Copper resistance
inch mm per inch per cm kcmil mm2 Ω/km

Ω/1000ft

0000 (4/0)

0.4600 11.684 2.17 0.856 212 107 0.1608 0.04901
000 (3/0) 0.4096 10.404 2.44 0.961 168 85.0 0.2028

0.06180

00 (2/0)

0.3648 9.266 2.74 1.08 133 67.4 0.2557 0.07793
0 (1/0) 0.3249 8.252 3.08 1.21 106 53.5 0.3224

0.09827

1

0.2893 7.348 3.46 1.36 83.7 42.4 0.4066 0.1239
2 0.2576 6.544 3.88 1.53 66.4 33.6 0.5127

0.1563

3

0.2294 5.827 4.36 1.72 52.6 26.7 0.6465 0.1970
4 0.2043 5.189 4.89 1.93 41.7 21.2 0.8152

0.2485

5

0.1819 4.621 5.50 2.16 33.1 16.8 1.028 0.3133
6 0.1620 4.115 6.17 2.43 26.3 13.3 1.296

0.3951

7

0.1443 3.665 6.93 2.73 20.8 10.5 1.634 0.4982
8 0.1285 3.264 7.78 3.06 16.5 8.37 2.061

0.6282

9

0.1144 2.906 8.74 3.44 13.1 6.63 2.599 0.7921
10 0.1019 2.588 9.81 3.86 10.4 5.26 3.277

0.9989

11

0.0907 2.305 11.0 4.34 8.23 4.17 4.132 1.260
12 0.0808 2.053 12.4 4.87 6.53 3.31 5.211

1.588

13

0.0720 1.828 13.9 5.47 5.18 2.62 6.571 2.003
14 0.0641 1.628 15.6 6.14 4.11 2.08 8.286

2.525

15

0.0571 1.450 17.5 6.90 3.26 1.65 10.45 3.184
16 0.0508 1.291 19.7 7.75 2.58 1.31 13.17

4.016

17

0.0453 1.150 22.1 8.70 2.05 1.04 16.61 5.064
18 0.0403 1.024 24.8 9.77 1.62 0.823 20.95

6.385

19

0.0359 0.912 27.9 11.0 1.29 0.653 26.42 8.051
20 0.0320 0.812 31.3 12.3 1.02 0.518 33.31

10.15

21

0.0285 0.723 35.1 13.8 0.810 0.410 42.00 12.80
22 0.0253 0.644 39.5 15.5 0.642 0.326 52.96

16.14

23

0.0226 0.573 44.3 17.4 0.509 0.258 66.79 20.36
24 0.0201 0.511 49.7 19.6 0.404 0.205 84.22

25.67

25

0.0179 0.455 55.9 22.0 0.320 0.162 106.2 32.37
26 0.0159 0.405 62.7 24.7 0.254 0.129 133.9

40.81

27

0.0142 0.361 70.4 27.7 0.202 0.102 168.9 51.47
28 0.0126 0.321 79.1 31.1 0.160 0.0810 212.9

64.90

29

0.0113 0.286 88.8 35.0 0.127 0.0642 268.5 81.84
30 0.0100 0.255 99.7 39.3 0.101 0.0509 338.6

103.2

31

0.00893 0.227 112 44.1 0.0797 0.0404 426.9 130.1
32 0.00795 0.202 126 49.5 0.0632 0.0320 538.3

164.1

33

0.00708 0.180 141 55.6 0.0501 0.0254 678.8 206.9
34 0.00630 0.160 159 62.4 0.0398 0.0201 856.0

260.9

35

0.00561 0.143 178 70.1 0.0315 0.0160 1079 329.0
36 0.00500 0.127 200 78.7 0.0250 0.0127 1361

414.8

37

0.00445 0.113 225 88.4 0.0198 0.0100 1716 523.1
38 0.00397 0.101 252 99.3 0.0157 0.00797 2164

659.6

39

0.00353 0.0897 283 111 0.0125 0.00632 2729 831.8
40 0.00314 0.0799 318 125 0.00989 0.00501 3441

1049

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:

120 Volt, Conductor size (AWG or kcmil)

Single Phase, Max 3% Voltage Drop*

Length of Run

25′ 50′ 100′ 150′ 200′
Copper 14 12 10 8 6

15 AMP**

Copper

12 12 8 6 4 20 AMP**
Copper 10 10 6 4 4

30 AMP**

Copper

1 1 1 2/0 4/0 100 AMP**
Aluminium 1/0 1/0 2/0 4/0 300 MCM

100 AMP**

Copper

3/0 3/0 3/0 300 MCM 500 MCM 200 AMP***
Aluminium 250 MCM 250 MCM 300 MCM 600 MCM 900 MCM

200 AMP***

Voltage Supply 240 Volts:

240 Volt, Conductor Size (AWG or kcmil)

Single Phase, Max 3% Voltage Drop*

Length of Run

25′ 50′ 100′ 150′ 200
Copper 14 14 12 10 10

15 AMP**

Copper

12 12 12 10 8 20 AMP**
Copper 10 10 10 8 6

30 AMP**

Aluminium

8 8 8 6 4 30 AMP**
Copper 8 8 8 6 4

40 AMP**

Aluminium

6 6 6 4 3 40 AMP**
Copper 6 6 6 6 4

50 AMP**

Aluminium

4 4 4 4 2

50 AMP**

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