Electrical Conduit Size Calculator [hot] May 2026

function calculateConduit() if (wires.length === 0) document.getElementById('resultArea').innerHTML = `<div class="conduit-size-result" style="background:#f1f5f9;">⚠️ No wires added</div>`; document.getElementById('fillDetails').innerHTML = ''; return; const conduitType = document.getElementById('conduitType').value; let sparePercent = parseFloat(document.getElementById('sparePercent').value); if (isNaN(sparePercent)) sparePercent = 0; const totalWireArea = computeTotalArea(); const numWires = wires.length; const fillLimit = getFillPercentLimit(numWires); const requiredArea = totalWireArea / fillLimit; const spareMultiplier = 1 + (sparePercent / 100); const finalRequiredArea = requiredArea * spareMultiplier; const areaMap = conduitAreas[conduitType]; if (!areaMap) document.getElementById('resultArea').innerHTML = `<div class="conduit-size-result">Error: conduit data</div>`; return; let selectedSize = null; for (let sz of tradeSizes) if (areaMap[sz] >= finalRequiredArea) selectedSize = sz; break; const fillPercentActual = (totalWireArea / (selectedSize ? areaMap[selectedSize] : 0.01)) * 100; const fillPercentLimited = fillLimit * 100; const resultDiv = document.getElementById('resultArea'); const fillDetailsDiv = document.getElementById('fillDetails'); const warningDiv = document.getElementById('warningMsg'); if (selectedSize) Required area with spare: $finalRequiredArea.toFixed(4) in²</div> <div>🔢 Number of conductors: $numWires</div> `; if (fillPercentActual > fillLimit*100 + 0.5) warningDiv.style.display = 'block'; warningDiv.innerHTML = `⚠️ Warning: Actual fill ($fillPercentActual.toFixed(1)%) exceeds NEC $fillLimit*100% limit. Choose larger conduit.`; else warningDiv.style.display = 'none'; else resultDiv.innerHTML = `<div class="conduit-size-result" style="background:#ffe6e5; color:#a1301a;">❌ No standard conduit size up to 4" fits these wires.<br>Consider larger conduit or reducing wires.</div>`; fillDetailsDiv.innerHTML = `<div>Total area needed: $finalRequiredArea.toFixed(4) in² exceeds max 4" conduit area ($ 'N/A')</div>`; warningDiv.style.display = 'none';

<div class="result-panel"> <h3 style="margin-top:0;">📊 Result</h3> <div class="result-card"> <div id="resultArea"> <div class="conduit-size-result" style="background:#f1f5f9; color:#2d3e50;"> -- / -- </div> <div id="fillDetails"></div> </div> </div> <div class="warning" id="warningMsg" style="display:none;"></div> <div class="note"> <strong>⚡ NEC Fill Reference (typical):</strong> <ul style="margin:8px 0 0 16px; padding-left:0;"> <li>1 conductor → 53% max fill</li> <li>2 conductors → 31% max fill</li> <li>3+ conductors → 40% max fill</li> </ul> <small>*Based on standard THHN/THWN area values. Actual conduit fill depends on insulation and jamming rules.</small> </div> </div> </div> electrical conduit size calculator

function renderWireInputs() const container = document.getElementById('wiresContainer'); if (!container) return; container.innerHTML = ''; wires.forEach((wire, idx) => const div = document.createElement('div'); div.className = 'wire-entry'; div.innerHTML = ` <div class="wire-header"> <span>🔌 Conductor #$idx+1</span> <button class="btn-remove" data-idx="$idx" type="button">Remove</button> </div> <div class="wire-controls"> <select class="wire-size" data-idx="$idx"> $Object.keys(wireAreas).map(sz => `<option value="$sz" $wire.size === sz ? 'selected' : ''>AWG $sz</option>`).join('') </select> <select class="wire-insulation" data-idx="$idx"> <option value="THHN" $wire.insulation === 'THHN' ? 'selected' : ''>THHN / THWN</option> <option value="XHHW" $wire.insulation === 'XHHW' ? 'selected' : ''>XHHW</option> </select> </div> `; container.appendChild(div); ); // attach remove events document.querySelectorAll('.btn-remove').forEach(btn => btn.addEventListener('click', (e) => const idx = parseInt(btn.getAttribute('data-idx')); wires.splice(idx, 1); renderWireInputs(); ); ); // attach change listeners for dynamic updates document.querySelectorAll('.wire-size').forEach(sel => sel.addEventListener('change', (e) => const idx = parseInt(sel.getAttribute('data-idx')); wires[idx].size = sel.value; ); ); document.querySelectorAll('.wire-insulation').forEach(sel => sel.addEventListener('change', (e) => const idx = parseInt(sel.getAttribute('data-idx')); wires[idx].insulation = sel.value; ); ); function calculateConduit() if (wires

function getFillPercentLimit(numWires) if (numWires === 1) return 0.53; if (numWires === 2) return 0.31; return 0.40; // 3+ wires Actual conduit fill depends on insulation and jamming rules

function addWire() wires.push( size: "12", insulation: "THHN" ); renderWireInputs();