Enter the nominal voltage of the circuit in Volts.
Enter the maximum expected current draw in Amperes.
Enter the total length of the wire run in feet.
Copper
Aluminum
Select the type of conductor material.
Enter the maximum acceptable voltage drop percentage (e.g., 3%).
Enter the AWG of the current wire (optional, for comparison).
Results
—
Enter values above to see results.
Calculated Voltage Drop: — V
Voltage Drop: — %
Required Wire Gauge (AWG): —
Recommended Wire Gauge (AWG): —
Wire Gauge vs. Voltage Drop
Wire Gauge vs. Voltage Drop for the given circuit parameters
Wire Gauge Data Table
Comparison of Common Wire Gauges
AWG
Diameter (in)
Area (kcmil)
Resistance (Ω/1000ft)
Ampacity (A)
Understanding Voltage Drop and Wire Sizing
{primary_keyword} is a critical concept in electrical engineering and home wiring, referring to the loss of electrical potential along the path of current flow through a conductor. Essentially, as electricity travels from the power source to a device, some energy is lost due to the resistance of the wires. This loss manifests as a reduction in voltage. Our advanced {primary_stock_keyword} calculator is designed to help you precisely quantify this phenomenon and select the appropriate wire size for your electrical projects, ensuring optimal performance and safety. Understanding {primary_stock_keyword} is fundamental for anyone involved in electrical installations, from DIY enthusiasts to professional electricians, as it directly impacts the efficiency and lifespan of electrical equipment.
The primary purpose of using a {primary_stock_keyword} calculator is to prevent issues arising from excessive voltage loss. When voltage drops too much, devices may not function correctly, leading to reduced efficiency, premature failure, or even complete malfunction. For instance, motors might run hotter and with less torque, lights might dim, and sensitive electronics could behave erratically. By calculating the expected {primary_stock_keyword} and comparing it against industry standards or project requirements, you can determine if your existing wiring is adequate or if a larger gauge wire is necessary. This proactive approach saves time, money, and potential hazards associated with under-spec'd wiring.
Who Should Use a {primary_stock_keyword} Calculator?
Homeowners: Planning new circuits, extending existing ones, or troubleshooting dimming lights and underperforming appliances.
Electricians: Ensuring code compliance, optimizing circuit performance, and selecting the correct wire size for residential, commercial, and industrial applications.
DIY Enthusiasts: Undertaking any electrical project, from installing new outlets to setting up complex audio-visual systems, to ensure safe and efficient operation.
Engineers: Designing electrical systems and calculating power distribution losses to maintain efficiency and reliability.
Common Misconceptions about {primary_stock_keyword}
"Wire size doesn't matter if the breaker is correctly sized." Breaker size protects against overcurrents, but doesn't prevent excessive voltage drop. A small wire can lead to voltage loss even if it doesn't trip the breaker.
"All copper wires are the same." While copper is a standard, purity and stranding can affect resistance slightly, though gauge is the dominant factor.
"Voltage drop is negligible in short runs." Even short runs can experience significant {primary_stock_keyword} if the current is high or the wire gauge is too small.
"AC and DC voltage drop are calculated the same way." While the core principles are similar, AC circuits involve inductance and capacitance, which can affect impedance, though for most common scenarios, the resistance-based calculation is a good approximation. This calculator focuses on the resistive component, which is dominant for wire sizing.
The {primary_stock_keyword} Formula and Mathematical Explanation
The fundamental formula for calculating voltage drop due to wire resistance in a DC circuit or a simple AC circuit (ignoring power factor for basic sizing) is derived from Ohm's Law ($V=IR$) and the formula for resistance of a conductor ($R = \rho \frac{L}{A}$).
The most common and practical formula for wire sizing, considering a round trip for the current (to the load and back), is:
$VD = \frac{2 \times K \times I \times L}{CM}$
Where:
VD = Voltage Drop (in Volts)
2 = Factor for the round trip (current goes out and back)
K = Electrical conductivity constant for the conductor material (e.g., 12.9 for copper, 21.2 for aluminum, in Ω⋅cmil/ft at 75°C)
I = Current flowing through the conductor (in Amperes)
L = One-way length of the conductor (in Feet)
CM = Circular Mil area of the conductor (in Circular Mils)
To determine the required wire gauge, we often rearrange this formula to solve for CM, or more practically, we use tables that list the circular mil area for standard wire gauges (AWG).
Alternatively, a simplified form often used is:
$VD = I \times R_{wire}$
Where $R_{wire}$ is the total resistance of the wire (calculated using resistivity, length, and cross-sectional area). For practical wire sizing, we often use the first formula directly or work with wire resistance tables.
The allowable voltage drop is typically expressed as a percentage of the source voltage:
Our calculator uses these principles to determine the minimum wire gauge (CM) needed to keep the voltage drop (VD) below the specified allowable limit.
Variable Definitions Table
Variable
Meaning
Unit
Typical Range / Notes
V (Voltage)
Nominal circuit voltage
Volts (V)
12, 24, 120, 240, 480
I (Current)
Maximum load current
Amperes (A)
0.1 to 1000+
L (Length)
One-way wire run length
Feet (ft)
1 to 1000+
K (Conductivity Constant)
Material property
Ω⋅cmil/ft
~12.9 (Copper), ~21.2 (Aluminum)
CM (Circular Mils)
Conductor cross-sectional area
Circular Mils (cmil)
Varies by AWG (e.g., 16510 for 12 AWG)
VD (Voltage Drop)
Calculated voltage loss
Volts (V)
Calculated value
Allowable VD (%)
Maximum acceptable voltage loss percentage
Percent (%)
1% to 5% (common recommendations)
AWG
American Wire Gauge
–
Standard sizes (e.g., 14, 12, 10, 8…)
Practical Examples (Real-World Use Cases)
Example 1: Lighting Circuit Extension
Scenario: A homeowner wants to add a new lighting circuit to their workshop. The circuit will be powered by a 120V source, run through a 15A breaker, and the total wire length from the panel to the furthest light fixture will be 75 feet. They want to limit the voltage drop to a maximum of 3% to ensure consistent light output.
Inputs:
Circuit Voltage: 120 V
Maximum Current: 15 A
Wire Length: 75 ft
Wire Material: Copper
Allowable Voltage Drop: 3%
Calculation Steps (as performed by the calculator):
Calculate allowable voltage drop in volts: $0.03 \times 120V = 3.6V$.
Using the formula $VD = \frac{2 \times K \times I \times L}{CM}$, we need to find the minimum CM required such that the calculated VD is less than or equal to 3.6V. Using K=12.9 for copper: $CM \ge \frac{2 \times 12.9 \times 15A \times 75ft}{3.6V}$.
$CM \ge \frac{29025}{3.6} \approx 8062.5$ cmil.
Results:
Calculated Voltage Drop: ~2.7 V (for a selected gauge)
Voltage Drop: ~2.25% (for a selected gauge)
Required Wire Gauge (AWG): Based on CM calculation, approximately 10 AWG (which has ~10380 cmil).
Recommended Wire Gauge (AWG): 10 AWG.
Interpretation: For this scenario, 12 AWG wire (which has 16510 cmil) would result in a voltage drop of approximately $\frac{2 \times 12.9 \times 15 \times 75}{16510} \approx 1.75V$ or 1.46%. This is well within the 3% limit. However, if they initially considered 14 AWG (4110 cmil), the voltage drop would be $\frac{2 \times 12.9 \times 15 \times 75}{4110} \approx 7.03V$ or 5.86%, which is too high. Therefore, for this 75 ft run with 15A current, 12 AWG is the appropriate choice to maintain efficiency and avoid dimming lights.
Example 2: Long Extension Cord for Power Tools
Scenario: A contractor needs a heavy-duty extension cord to power a tool that draws 20 Amperes. The cord needs to be 100 feet long. They want to limit the voltage drop to 5% to ensure the tool operates at its rated power and efficiency. They are considering using aluminum wire for cost-effectiveness.
Inputs:
Circuit Voltage: 120 V
Maximum Current: 20 A
Wire Length: 100 ft
Wire Material: Aluminum
Allowable Voltage Drop: 5%
Calculation Steps:
Calculate allowable voltage drop in volts: $0.05 \times 120V = 6.0V$.
Using the formula $VD = \frac{2 \times K \times I \times L}{CM}$ with K=21.2 for aluminum: $CM \ge \frac{2 \times 21.2 \times 20A \times 100ft}{6.0V}$.
$CM \ge \frac{84800}{6.0} \approx 14133$ cmil.
Results:
Calculated Voltage Drop: ~4.24 V (for a selected gauge)
Voltage Drop: ~3.53% (for a selected gauge)
Required Wire Gauge (AWG): Based on CM calculation, approximately 8 AWG (which has 16510 cmil).
Recommended Wire Gauge (AWG): 8 AWG.
Interpretation: Using aluminum wire, the calculation shows that approximately 14133 cmil is required. Standard 10 AWG aluminum wire has about 10380 cmil, which would result in a voltage drop of ~5.77V (4.8%), potentially acceptable but pushing the limit. However, standard 8 AWG aluminum wire has 16510 cmil. Using 8 AWG aluminum would yield a voltage drop of $\frac{2 \times 21.2 \times 20 \times 100}{16510} \approx 5.1V$ or 4.25%, which is comfortably within the 5% limit. Therefore, 8 AWG aluminum wire is recommended for this application to ensure the tool receives adequate power.
How to Use This {primary_stock_keyword} Calculator
Using our {primary_stock_keyword} calculator is straightforward. Follow these steps to determine the appropriate wire size for your electrical project:
Enter Circuit Voltage: Input the nominal voltage of your electrical system (e.g., 120V, 240V).
Input Maximum Current: Specify the maximum current (in Amperes) that the circuit is expected to draw. This is often determined by the rating of the circuit breaker or the power consumption of the largest device on the circuit.
Measure Wire Length: Accurately measure the total one-way length of the wire run from the power source (e.g., breaker panel) to the load (e.g., outlet, fixture). Double this length for the total conductor path.
Select Wire Material: Choose whether your wiring will be copper or aluminum. Copper has lower resistance than aluminum, allowing for smaller gauges for the same voltage drop.
Set Allowable Voltage Drop: Enter the maximum percentage of voltage drop you can tolerate. Common recommendations are 3% for branch circuits and 5% for feeders, but specific applications might have different requirements. A lower percentage ensures better performance but may require larger, more expensive wires.
Input Current Wire Gauge (Optional): If you are evaluating an existing circuit or comparing against a specific wire size, enter its AWG. This helps in assessing if the current setup is adequate.
Click Calculate: Once all fields are populated, press the "Calculate" button.
Interpreting Results:
Calculated Voltage Drop (V): This is the expected voltage loss in Volts based on your inputs.
Voltage Drop (%): This shows the voltage drop as a percentage of the source voltage. Compare this to your "Allowable Voltage Drop."
Required Wire Gauge (AWG): This indicates the smallest standard wire gauge (AWG) that meets your specified allowable voltage drop.
Recommended Wire Gauge (AWG): This is the practical recommendation, often rounding up to the next standard size if the required gauge is not standard or if the calculated gauge is very close to the limit. It's generally safer to choose a wire size that results in a voltage drop significantly below the maximum allowable.
Decision-Making Guidance: If the "Calculated Voltage Drop %" is less than or equal to your "Allowable Voltage Drop %," your current or planned wire size is likely adequate. If it exceeds the allowable limit, you must upgrade to a larger gauge wire (smaller AWG number) as indicated by the "Required" or "Recommended" gauge. Always consult local electrical codes for specific requirements.
Key Factors That Affect {primary_stock_keyword} Results
Several factors influence the amount of voltage drop in an electrical circuit. Understanding these is crucial for accurate calculations and effective {primary_stock_keyword} management:
Wire Gauge (AWG): This is the most significant factor. Thicker wires (smaller AWG numbers) have lower resistance per unit length, resulting in less voltage drop for the same current and length. Choosing the correct wire gauge is paramount for minimizing {primary_stock_keyword}.
Wire Length: Voltage drop is directly proportional to the length of the wire run. Longer distances mean more resistance, and thus a greater voltage drop. For long runs, a larger wire gauge is often necessary to compensate.
Current Load (Amperes): Voltage drop increases with the amount of current flowing through the wire. Higher current loads demand thicker wires to maintain acceptable voltage levels. Ensure your calculated current accounts for the peak load.
Conductor Material: Different materials have different resistivities. Copper has lower resistivity than aluminum, meaning copper wires offer less resistance and thus less voltage drop compared to aluminum wires of the same gauge and length. While aluminum is lighter and cheaper, it requires larger gauges for equivalent performance.
Temperature: The resistance of conductors increases with temperature. While standard calculations often use values at a specific temperature (e.g., 75°C for copper), significant temperature fluctuations in the installation environment can slightly alter the actual voltage drop.
Frequency (for AC Circuits): In AC circuits, particularly at higher frequencies or with large conductors, skin effect and proximity effect can increase the effective resistance of the wire. Skin effect causes current to flow more on the surface of the conductor, effectively reducing the cross-sectional area available for current flow. This calculator primarily uses the DC resistance formula, which is accurate for most common residential and light commercial low-frequency applications. For high-frequency or very large conductors, more complex calculations may be needed.
Allowable Voltage Drop Percentage: This is not a factor that *causes* voltage drop, but rather a critical parameter set by the user or code that determines the *acceptable limit*. A tighter limit (e.g., 1% vs 5%) will necessitate a larger wire gauge.
Frequently Asked Questions (FAQ)
Q1: What is the NEC (National Electrical Code) recommendation for voltage drop?
A: The NEC recommends limiting voltage drop to 3% for branch circuits and 5% total for feeders and branch circuits combined. However, these are recommendations, not mandatory code requirements, unless specifically adopted by local jurisdiction. Always check local codes.
Q2: Can I use a smaller wire gauge if the voltage drop is within limits but the ampacity is borderline?
A: No. Wire selection must satisfy both ampacity (current-carrying capacity to prevent overheating) and voltage drop requirements. Always select the larger wire gauge if one requirement necessitates it.
Q3: Does the "round trip" factor in the formula account for multi-wire branch circuits?
A: The factor '2' in the formula $VD = \frac{2 \times K \times I \times L}{CM}$ accounts for the current traveling out to the load and returning. For typical single-phase circuits, this is correct. For multi-wire branch circuits (MWBCs) with shared neutral, the calculation can become more complex due to neutral current interactions. However, for sizing the individual phase conductors and the neutral based on maximum expected load, using the standard formula for each conductor is a common and safe practice.
Q4: How does using conduit affect voltage drop?
A: Conduit itself does not add resistance. However, running multiple current-carrying conductors (including the neutral) in the same conduit can require derating their ampacity due to heat buildup. This increased ampacity requirement might indirectly necessitate a larger wire gauge, thus affecting the final voltage drop calculation if the derated ampacity is lower than the calculated load.
Q5: Is aluminum wire safe for household wiring?
A: Yes, aluminum wiring is safe and widely used, especially for larger gauge applications like service entrance cables and feeders, due to its lower cost and weight compared to copper. However, it requires specific termination techniques and devices (marked AL/CU) to prevent oxidation and ensure reliable connections, as aluminum expands and contracts more than copper with temperature changes.
Q6: What happens if the voltage drop is too high?
A: High voltage drop can lead to reduced performance of electrical devices (dim lights, weak motors), increased energy consumption due to wasted power as heat, and potential damage to equipment over time. It can also cause intermittent issues and make troubleshooting difficult.
Q7: Should I use the AWG of my current wire or the required AWG for calculation?
A: For calculating the *required* wire size, use the current load, length, and voltage. The "Required Wire Gauge (AWG)" output is what you *need*. If you entered a "Current Wire Gauge (AWG)," the calculator will show you the voltage drop associated with *that* specific gauge for comparison, helping you decide if an upgrade is necessary.
Q8: How does power factor affect voltage drop?
A: The formula used in this calculator primarily accounts for resistive voltage drop ($V=IR$). In AC circuits with significant inductive or capacitive loads (low power factor), the total impedance (Z), which includes resistance (R) and reactance (X), determines the current flow ($I = V/Z$). Voltage drop is then $VD = I \times Z$. For most practical wire sizing scenarios, especially with mixed loads or where resistance dominates, the simplified formula based on resistance provides a sufficiently accurate estimate. However, for highly inductive loads or complex power factor considerations, a more detailed impedance calculation might be necessary.
Related Tools and Internal Resources
Circuit Breaker CalculatorDetermine the appropriate circuit breaker size based on load current and wire ampacity.
Ohm's Law CalculatorSolve for voltage, current, or resistance using Ohm's Law ($V=IR$). Essential for basic electrical calculations.
Electrical Wiring Basics GuideLearn fundamental principles of safe and effective electrical wiring for homes and projects.
// Global variables for chart and table data
var voltageDropChartInstance = null;
var wireGaugeTableBody = document.getElementById('wireGaugeTable').getElementsByTagName('tbody')[0];
// Wire Gauge Data (Simplified for demonstration, can be expanded)
// Based on solid copper, THHN insulation approx 75°C
var wireGaugeData = [
{ awg: 14, diameter_in: 0.0641, area_kcmil: 4110, resistance_ohm_1000ft: 2.57, ampacity_a: 25 },
{ awg: 12, diameter_in: 0.0804, area_kcmil: 6530, resistance_ohm_1000ft: 1.62, ampacity_a: 35 },
{ awg: 10, diameter_in: 0.1019, area_kcmil: 10380, resistance_ohm_1000ft: 1.02, ampacity_a: 45 },
{ awg: 8, diameter_in: 0.1285, area_kcmil: 16510, resistance_ohm_1000ft: 0.640, ampacity_a: 65 },
{ awg: 6, diameter_in: 0.1620, area_kcmil: 26240, resistance_ohm_1000ft: 0.402, ampacity_a: 85 },
{ awg: 4, diameter_in: 0.2043, area_kcmil: 41740, resistance_ohm_1000ft: 0.253, ampacity_a: 115 },
{ awg: 2, diameter_in: 0.2576, area_kcmil: 66360, resistance_ohm_1000ft: 0.159, ampacity_a: 150 },
{ awg: 1, diameter_in: 0.2893, area_kcmil: 83690, resistance_ohm_1000ft: 0.126, ampacity_a: 175 },
{ awg: 1000, diameter_in: 0.3249, area_kcmil: 105600, resistance_ohm_1000ft: 0.100, ampacity_a: 200 } // Placeholder for 1/0 AWG
];
// K values (approximate, at 75°C)
var kValues = {
copper: 12.9,
aluminum: 21.2
};
// Function to validate input
function validateInput(id, value, min, max, allowEmpty, errorId, isDecimal = true) {
var errorElement = document.getElementById(errorId);
errorElement.style.display = 'none'; // Hide error initially
if (value === "" && !allowEmpty) {
errorElement.textContent = "This field cannot be empty.";
errorElement.style.display = 'block';
return false;
}
if (value === "" && allowEmpty) {
return true; // Allow empty if specified
}
var numValue = isDecimal ? parseFloat(value) : parseInt(value);
if (isNaN(numValue)) {
errorElement.textContent = "Please enter a valid number.";
errorElement.style.display = 'block';
return false;
}
if (numValue < 0) {
errorElement.textContent = "Value cannot be negative.";
errorElement.style.display = 'block';
return false;
}
if (min !== null && numValue max) {
errorElement.textContent = "Value cannot exceed " + max + ".";
errorElement.style.display = 'block';
return false;
}
return true;
}
// Function to get resistance per foot based on AWG
function getResistancePerFoot(awg, material) {
for (var i = 0; i < wireGaugeData.length; i++) {
if (wireGaugeData[i].awg == awg) {
var resOhmsPer1000ft = wireGaugeData[i].resistance_ohm_1000ft;
// Adjust resistance for material if needed (though data is mostly copper-based, K factor handles it)
// For simplicity, we use the K factor in the main formula. If we were to use R=rho*L/A, we'd need rho per material.
return resOhmsPer1000ft / 1000; // Resistance per foot
}
}
return null; // AWG not found
}
// Function to get CM area based on AWG
function getCmArea(awg) {
for (var i = 0; i = 0; i–) { // Check from largest wire (smallest AWG number) first
var currentCm = wireGaugeData[i].area_kcmil * 1000;
if (currentCm >= requiredCm) {
bestAwg = wireGaugeData[i].awg;
// We found a suitable AWG, but continue to find the closest match if needed,
// though typically we just need the smallest standard AWG that meets the requirement.
}
}
// If requiredCm is very small, it might fall below the smallest wire gauge we have data for.
// Default to the smallest gauge we have if requiredCm is positive but no match is found above.
if (bestAwg === null && requiredCm > 0) {
bestAwg = wireGaugeData[wireGaugeData.length – 1].awg; // Smallest AWG in our list (e.g., 14)
} else if (requiredCm <= 0) {
return "N/A (No wire needed)";
}
return bestAwg;
}
// Function to find the smallest standard AWG that meets or exceeds a given CM requirement.
// This is the core logic for determining the required wire size.
function findRequiredAwg(requiredCm) {
var suitableAwg = null;
// Iterate from smallest AWG number (largest wire) to largest AWG number (smallest wire)
for (var i = 0; i = requiredCm) {
suitableAwg = wireGaugeData[i].awg;
break; // Found the first (smallest) AWG that meets the requirement
}
}
// If requiredCm is positive but no standard AWG meets it (e.g., extremely high requirement),
// return the largest gauge we have data for.
if (suitableAwg === null && requiredCm > 0) {
return wireGaugeData[wireGaugeData.length – 1].awg; // Return the smallest wire gauge we have (e.g., 14)
} else if (requiredCm CM = (2 * K * I * L) / VD
var requiredCm = (2 * k * current * length) / allowableDropVolts;
if (!isNaN(requiredCm) && requiredCm > 0) {
// Find the standard AWG that meets or exceeds the required CM
requiredWireGauge = findRequiredAwg(requiredCm);
if (requiredWireGauge !== "N/A (No wire needed)") {
var requiredCmArea = getCmArea(requiredWireGauge);
if (requiredCmArea) {
// Calculate actual VD for the required gauge to display
calculatedVDVolts = (2 * k * current * length) / requiredCmArea;
calculatedVDPercent = (calculatedVDVolts / voltage) * 100;
}
} else {
calculatedVDVolts = 0;
calculatedVDPercent = 0;
}
} else {
calculatedVDVolts = 0;
calculatedVDPercent = 0;
}
}
// — Handle Current Wire Gauge Comparison (if provided) —
var currentWireVdVolts = '–';
var currentWireVdPercent = '–';
var currentWireAmpacity = '–';
if (currentWireGauge !== null) {
var currentCmArea = getCmArea(currentWireGauge);
if (currentCmArea) {
currentWireVdVolts = (2 * k * current * length) / currentCmArea;
currentWireVdPercent = (currentWireVdVolts / voltage) * 100;
// Find ampacity for the current wire gauge
for (var i = 0; i < wireGaugeData.length; i++) {
if (wireGaugeData[i].awg == currentWireGauge) {
currentWireAmpacity = wireGaugeData[i].ampacity_a;
break;
}
}
}
}
// — Determine Recommended Wire Gauge —
// Recommendation is usually the required gauge, or the next size up if the required is very close to the limit
recommendedWireGauge = requiredWireGauge; // Start with the calculated required gauge
// Check if current wire gauge (if provided) is sufficient
var isCurrentGaugeSufficient = false;
if (currentWireGauge !== null && requiredWireGauge !== '–') {
// Compare AWG numbers: smaller AWG number means larger wire
if (currentWireGauge = current) {
recommendedWireGauge = currentWireGauge; // Recommend keeping current gauge if it's adequate
} else if (requiredWireGauge !== '–') {
recommendedWireGauge = requiredWireGauge; // Otherwise, recommend the calculated required gauge
}
// — Display Results —
var resultElement = document.getElementById('result');
var vdVoltsElement = document.getElementById('calculatedVoltageDropVolts').querySelector('span');
var vdPercentElement = document.getElementById('calculatedVoltageDropPercent').querySelector('span');
var reqGaugeElement = document.getElementById('requiredWireGauge').querySelector('span');
var recGaugeElement = document.getElementById('recommendedWireGauge').querySelector('span');
if (requiredWireGauge !== '–') {
resultElement.textContent = recommendedWireGauge;
vdVoltsElement.textContent = calculatedVDVolts.toFixed(2) + " V";
vdPercentElement.textContent = calculatedVDPercent.toFixed(2) + " %";
reqGaugeElement.textContent = requiredWireGauge;
recGaugeElement.textContent = recommendedWireGauge;
var explanation = "The calculated voltage drop is " + calculatedVDPercent.toFixed(2) + "% (" + calculatedVDVolts.toFixed(2) + "V). ";
if (recommendedWireGauge !== '–') {
explanation += "A wire gauge of " + recommendedWireGauge + " AWG is recommended to keep the voltage drop within " + allowableDropPercent + "%.";
} else {
explanation += "The current wiring appears sufficient based on the inputs.";
}
if (currentWireGauge !== null) {
explanation += " (Current gauge " + currentWireGauge + " AWG has " + currentWireVdPercent.toFixed(2) + "% drop and " + currentWireAmpacity + "A ampacity).";
}
document.getElementById('result-explanation').textContent = explanation;
resultElement.style.color = "#28a745"; // Success color
} else {
resultElement.textContent = "N/A";
vdVoltsElement.textContent = "–";
vdPercentElement.textContent = "–";
reqGaugeElement.textContent = "–";
recGaugeElement.textContent = "–";
document.getElementById('result-explanation').textContent = "Unable to calculate. Please check inputs.";
resultElement.style.color = "#dc3545″; // Error color
}
// Update chart
updateChart(voltage, current, length, wireMaterial);
}
function resetCalculator() {
document.getElementById('voltage').value = ";
document.getElementById('current').value = ";
document.getElementById('length').value = ";
document.getElementById('wireMaterial').value = 'copper';
document.getElementById('allowableDropPercent').value = '3';
document.getElementById('wireGauge').value = ";
document.getElementById('result').textContent = "–";
document.getElementById('result-explanation').textContent = "Enter values above to see results.";
document.getElementById('calculatedVoltageDropVolts').querySelector('span').textContent = "–";
document.getElementById('calculatedVoltageDropPercent').querySelector('span').textContent = "–";
document.getElementById('requiredWireGauge').querySelector('span').textContent = "–";
document.getElementById('recommendedWireGauge').querySelector('span').textContent = "–";
// Clear errors
var errorElements = document.querySelectorAll('.error-message');
for (var i = 0; i < errorElements.length; i++) {
errorElements[i].style.display = 'none';
}
// Reset chart
if (voltageDropChartInstance) {
voltageDropChartInstance.destroy();
voltageDropChartInstance = null;
}
drawInitialChart();
}
function copyResults() {
var mainResult = document.getElementById('result').innerText;
var resultExplanation = document.getElementById('result-explanation').innerText;
var vdVolts = document.getElementById('calculatedVoltageDropVolts').querySelector('span').innerText;
var vdPercent = document.getElementById('calculatedVoltageDropPercent').querySelector('span').innerText;
var reqGauge = document.getElementById('requiredWireGauge').querySelector('span').innerText;
var recGauge = document.getElementById('recommendedWireGauge').querySelector('span').innerText;
var textToCopy = "Voltage Drop Calculator Results:\n";
textToCopy += "Recommended Wire Gauge: " + mainResult + "\n";
textToCopy += "Details: " + resultExplanation + "\n";
textToCopy += "Calculated Voltage Drop: " + vdVolts + " (" + vdPercent + ")\n";
textToCopy += "Required Wire Gauge (AWG): " + reqGauge + "\n";
textToCopy += "Recommended Wire Gauge (AWG): " + recGauge + "\n";
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textArea.style.top = 0;
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textArea.style.border = 'none';
textArea.style.outline = 'none';
textArea.style.boxShadow = 'none';
document.body.appendChild(textArea);
try {
textArea.focus();
var successful = document.execCommand('copy');
var msg = successful ? 'Copied!' : 'Copy failed';
console.log('Copying text command was ' + msg);
// Optionally show a temporary message to the user
var copyButton = document.querySelector('.copy-btn');
var originalText = copyButton.innerText;
copyButton.innerText = 'Copied!';
setTimeout(function() { copyButton.innerText = originalText; }, 2000);
} catch (err) {
console.log('Unable to copy text.', err);
}
document.body.removeChild(textArea);
}
// — Charting Functions —
// Function to populate the wire gauge data table
function populateWireGaugeTable() {
var html = '';
// Sort data by AWG for display
wireGaugeData.sort(function(a, b) { return a.awg – b.awg; });
for (var i = 0; i < wireGaugeData.length; i++) {
html += '