.voltage-drop-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 700px;
margin: 20px auto;
padding: 25px;
border: 1px solid #e0e0e0;
border-radius: 10px;
background-color: #f9f9f9;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}
.voltage-drop-calculator-container h2 {
text-align: center;
color: #333;
margin-bottom: 25px;
font-size: 28px;
font-weight: 600;
}
.voltage-drop-calculator-container .input-group {
margin-bottom: 18px;
display: flex;
flex-direction: column;
}
.voltage-drop-calculator-container label {
margin-bottom: 8px;
color: #555;
font-size: 16px;
font-weight: 500;
}
.voltage-drop-calculator-container input[type="number"],
.voltage-drop-calculator-container select {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.3s ease;
}
.voltage-drop-calculator-container input[type="number"]:focus,
.voltage-drop-calculator-container select:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}
.voltage-drop-calculator-container button {
display: block;
width: 100%;
padding: 14px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: 600;
cursor: pointer;
transition: background-color 0.3s ease, transform 0.2s ease;
margin-top: 25px;
}
.voltage-drop-calculator-container button:hover {
background-color: #0056b3;
transform: translateY(-2px);
}
.voltage-drop-calculator-container #voltageDropResult {
margin-top: 30px;
padding: 20px;
border: 1px solid #d4edda;
background-color: #e2f0e4;
border-radius: 8px;
font-size: 18px;
color: #155724;
text-align: center;
line-height: 1.6;
font-weight: 500;
}
.voltage-drop-calculator-container #voltageDropResult strong {
color: #0a3622;
}
.voltage-drop-calculator-container #voltageDropResult .warning {
color: #856404;
background-color: #fff3cd;
border-color: #ffeeba;
padding: 10px;
border-radius: 5px;
margin-top: 15px;
font-weight: 600;
}
.voltage-drop-calculator-container #voltageDropResult .error {
color: #721c24;
background-color: #f8d7da;
border-color: #f5c6cb;
padding: 10px;
border-radius: 5px;
margin-top: 15px;
font-weight: 600;
}
.voltage-drop-calculator-container .calculator-info {
margin-top: 30px;
padding-top: 20px;
border-top: 1px solid #e0e0e0;
color: #666;
font-size: 15px;
line-height: 1.6;
}
.voltage-drop-calculator-container .calculator-info h3 {
color: #333;
font-size: 22px;
margin-bottom: 15px;
}
.voltage-drop-calculator-container .calculator-info ul {
list-style-type: disc;
margin-left: 20px;
padding-left: 0;
}
.voltage-drop-calculator-container .calculator-info li {
margin-bottom: 8px;
}
function calculateVoltageDrop() {
var conductorLength = parseFloat(document.getElementById('conductorLength').value);
var current = parseFloat(document.getElementById('current').value);
var systemVoltage = parseFloat(document.getElementById('systemVoltage').value);
var conductorMaterial = document.getElementById('conductorMaterial').value;
var conductorGauge = document.getElementById('conductorGauge').value;
var phases = document.getElementById('phases').value;
var resultDiv = document.getElementById('voltageDropResult');
// Clear previous results
resultDiv.innerHTML = ";
// Input validation
if (isNaN(conductorLength) || conductorLength <= 0) {
resultDiv.innerHTML = 'Voltage Drop Calculator
Copper
Aluminum
14 AWG
12 AWG
10 AWG
8 AWG
6 AWG
4 AWG
2 AWG
1/0 AWG
2/0 AWG
3/0 AWG
4/0 AWG
250 kcmil
300 kcmil
350 kcmil
400 kcmil
500 kcmil
12 AWG
10 AWG
8 AWG
6 AWG
4 AWG
2 AWG
1/0 AWG
2/0 AWG
3/0 AWG
4/0 AWG
250 kcmil
300 kcmil
350 kcmil
400 kcmil
500 kcmil
Single Phase
Three Phase
Understanding Voltage Drop
Voltage drop is the reduction in electrical potential along the length of a conductor carrying current. It's a critical factor in electrical system design, impacting efficiency, performance, and safety.
Why is Voltage Drop Important?
- Reduced Efficiency: Lower voltage at the load means less power delivered, leading to wasted energy and higher electricity bills.
- Poor Equipment Performance: Motors may run hotter, lights may dim, and electronic equipment may malfunction or have a shorter lifespan if operating below their specified voltage range.
- Safety Concerns: Excessive voltage drop can lead to overheating of conductors, posing a fire hazard, especially if the conductor is undersized.
- Compliance: Electrical codes (like the National Electrical Code in the US) often recommend maximum voltage drop percentages for various circuits.
Factors Affecting Voltage Drop:
The amount of voltage drop is influenced by several key factors:
- Conductor Length: The longer the wire, the greater the resistance, and thus the greater the voltage drop.
- Current (Amperes): Higher current flowing through the conductor results in a larger voltage drop.
- Conductor Material: Different materials have different resistivity. Copper has lower resistivity than aluminum, meaning it offers less resistance for the same size and length.
- Conductor Gauge (Wire Size): Thicker wires (smaller AWG numbers or larger kcmil numbers) have lower resistance and therefore less voltage drop.
- Number of Phases: Three-phase systems inherently distribute current more efficiently, resulting in less voltage drop compared to single-phase systems for the same power delivery.
Recommended Voltage Drop Limits:
While not always strictly mandated by code, common industry recommendations for voltage drop are:
- Branch Circuits: Typically 3% maximum.
- Feeders: Typically 3% maximum.
- Total (Feeder + Branch): Typically 5% maximum.
These limits help ensure optimal performance and longevity of electrical equipment.
How to Use This Calculator:
- Conductor Length: Enter the one-way length of the wire run in feet.
- Current: Input the expected maximum current (load) in Amperes.
- System Voltage: Specify the nominal voltage of your electrical system (e.g., 120V, 240V, 208V, 480V).
- Conductor Material: Select whether your wire is Copper or Aluminum.
- Conductor Gauge: Choose the AWG or kcmil size of your conductor.
- Number of Phases: Indicate if your system is Single Phase or Three Phase.
- Click "Calculate Voltage Drop" to see the results.
Example Calculation:
Let's say you have a 100-foot run of 12 AWG copper wire carrying 20 Amperes on a 120V single-phase circuit.
- Conductor Length: 100 feet
- Current: 20 Amperes
- System Voltage: 120 Volts
- Conductor Material: Copper
- Conductor Gauge: 12 AWG
- Number of Phases: Single Phase
Using the calculator with these values, you would find a voltage drop of approximately 0.76 Volts, which is about 0.63% of the system voltage. This is well within the recommended 3% limit.
Please enter a valid Conductor Length (must be a positive number).
';
return;
}
if (isNaN(current) || current <= 0) {
resultDiv.innerHTML = 'Please enter a valid Current (must be a positive number).
';
return;
}
if (isNaN(systemVoltage) || systemVoltage <= 0) {
resultDiv.innerHTML = 'Please enter a valid System Voltage (must be a positive number).
';
return;
}
// Resistance per 1000 feet (Ohms/1000ft) at 75°C (approximate values for common applications)
// Source: NEC Chapter 9, Table 8 (DC Resistance at 75°C) – adjusted for AC impedance where applicable, or common industry values.
var resistancePer1000ft = {
// Copper
'copper': {
'14': 3.1, '12': 1.9, '10': 1.2, '8': 0.76, '6': 0.49, '4': 0.31, '2': 0.20,
'1/0': 0.12, '2/0': 0.097, '3/0': 0.077, '4/0': 0.061,
'250': 0.052, '300': 0.043, '350': 0.037, '400': 0.033, '500': 0.026
},
// Aluminum (approx. 1.6 times copper resistance for same gauge, or specific values)
'aluminum': {
'12_AL': 3.1, '10_AL': 1.9, '8_AL': 1.2, '6_AL': 0.79, '4_AL': 0.50, '2_AL': 0.32,
'1/0_AL': 0.20, '2/0_AL': 0.16, '3/0_AL': 0.12, '4/0_AL': 0.097,
'250_AL': 0.084, '300_AL': 0.069, '350_AL': 0.060, '400_AL': 0.053, '500_AL': 0.042
}
};
var R = 0;
if (conductorMaterial === 'copper') {
R = resistancePer1000ft.copper[conductorGauge];
} else if (conductorMaterial === 'aluminum') {
R = resistancePer1000ft.aluminum[conductorGauge];
}
if (R === undefined) {
resultDiv.innerHTML = 'Could not find resistance value for the selected material and gauge. Please check your selection.
';
return;
}
var voltageDrop = 0;
if (phases === 'single') {
// Single Phase Voltage Drop (VD = (2 * R * I * L) / 1000)
// 2 because current flows out and back, so length is doubled for resistance calculation
voltageDrop = (2 * R * current * conductorLength) / 1000;
} else if (phases === 'three') {
// Three Phase Voltage Drop (VD = (sqrt(3) * R * I * L) / 1000)
voltageDrop = (Math.sqrt(3) * R * current * conductorLength) / 1000;
}
var percentageVoltageDrop = (voltageDrop / systemVoltage) * 100;
var resultHtml = 'Calculated Voltage Drop: ' + voltageDrop.toFixed(2) + ' Volts';
resultHtml += 'Percentage Voltage Drop: ' + percentageVoltageDrop.toFixed(2) + '%';
if (percentageVoltageDrop > 5) {
resultHtml += 'Warning: This voltage drop (' + percentageVoltageDrop.toFixed(2) + '%) is higher than the generally recommended maximum of 5% for total circuits. Consider increasing wire gauge or reducing length/current.
';
} else if (percentageVoltageDrop > 3) {
resultHtml += 'Note: This voltage drop (' + percentageVoltageDrop.toFixed(2) + '%) is higher than the generally recommended maximum of 3% for feeders or branch circuits.
';
} else {
resultHtml += 'This voltage drop is within generally accepted limits.';
}
resultDiv.innerHTML = resultHtml;
}
// Function to update gauge options based on material selection
function updateGaugeOptions() {
var materialSelect = document.getElementById('conductorMaterial');
var gaugeSelect = document.getElementById('conductorGauge');
var selectedMaterial = materialSelect.value;
// Clear existing options
gaugeSelect.innerHTML = ";
// Define gauge options for copper and aluminum
var copperGauges = [
{ value: '14', text: '14 AWG' }, { value: '12', text: '12 AWG' }, { value: '10', text: '10 AWG' },
{ value: '8', text: '8 AWG' }, { value: '6', text: '6 AWG' }, { value: '4', text: '4 AWG' },
{ value: '2', text: '2 AWG' }, { value: '1/0', text: '1/0 AWG' }, { value: '2/0', text: '2/0 AWG' },
{ value: '3/0', text: '3/0 AWG' }, { value: '4/0', text: '4/0 AWG' },
{ value: '250', text: '250 kcmil' }, { value: '300', text: '300 kcmil' },
{ value: '350', text: '350 kcmil' }, { value: '400', text: '400 kcmil' }, { value: '500', text: '500 kcmil' }
];
var aluminumGauges = [
{ value: '12_AL', text: '12 AWG' }, { value: '10_AL', text: '10 AWG' }, { value: '8_AL', text: '8 AWG' },
{ value: '6_AL', text: '6 AWG' }, { value: '4_AL', text: '4 AWG' }, { value: '2_AL', text: '2 AWG' },
{ value: '1/0_AL', text: '1/0 AWG' }, { value: '2/0_AL', text: '2/0 AWG' }, { value: '3/0_AL', text: '3/0 AWG' },
{ value: '4/0_AL', text: '4/0 AWG' },
{ value: '250_AL', text: '250 kcmil' }, { value: '300_AL', text: '300 kcmil' },
{ value: '350_AL', text: '350 kcmil' }, { value: '400_AL', text: '400 kcmil' }, { value: '500_AL', text: '500 kcmil' }
];
var optgroupCopper = document.createElement('optgroup');
optgroupCopper.label = "Copper";
copperGauges.forEach(function(gauge) {
var option = document.createElement('option');
option.value = gauge.value;
option.text = gauge.text;
optgroupCopper.appendChild(option);
});
var optgroupAluminum = document.createElement('optgroup');
optgroupAluminum.label = "Aluminum";
aluminumGauges.forEach(function(gauge) {
var option = document.createElement('option');
option.value = gauge.value;
option.text = gauge.text;
optgroupAluminum.appendChild(option);
});
if (selectedMaterial === 'copper') {
gaugeSelect.appendChild(optgroupCopper);
// Set a default selected value for copper if needed
gaugeSelect.value = '12';
} else if (selectedMaterial === 'aluminum') {
gaugeSelect.appendChild(optgroupAluminum);
// Set a default selected value for aluminum if needed
gaugeSelect.value = '12_AL';
}
}
// Attach event listener to material selection
document.getElementById('conductorMaterial').onchange = updateGaugeOptions;
// Initialize gauge options on page load
updateGaugeOptions();