NJ Residential Electrical Load Calculator

ANA›Life Services Authority›National Calculator Authority›NJ Residential Electrical Load Calculator

.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }

NJ Residential Electrical Load Calculator

Calculate the minimum electrical service size for a New Jersey residential dwelling using the NEC Article 220 Standard Load Calculation method, as adopted by the New Jersey Department of Community Affairs (DCA).

### Dwelling Information

Finished Floor Area (sq ft)

### Fixed Appliances (240V)

Electric Range / Cooktop (watts, 0 if gas)

Electric Clothes Dryer (watts, 0 if gas)

Electric Water Heater (watts, 0 if gas)

Dishwasher (watts)

Garbage Disposal (watts)

Built-in Microwave (watts)

Other Fixed Appliances Total (watts)

### HVAC

Air Conditioning / Heat Pump (watts, largest unit)

Electric Heat (watts, total all units)

### EV Charging (if applicable)

EV Charger Load (watts, 0 if none)

### Service Voltage

Service Voltage

240V Single-Phase (standard residential) 208V (rare, multi-family)

Calculate Service Load

function njCalc() { // --- Gather inputs --- var sqft = parseFloat(document.getElementById('nj-sqft').value); var rangW = parseFloat(document.getElementById('nj-range').value) || 0; var dryerW = parseFloat(document.getElementById('nj-dryer').value) || 0; var whW = parseFloat(document.getElementById('nj-wh').value) || 0; var dwW = parseFloat(document.getElementById('nj-dw').value) || 0; var dispW = parseFloat(document.getElementById('nj-disposal').value) || 0; var microW = parseFloat(document.getElementById('nj-microwave').value) || 0; var otherFixed = parseFloat(document.getElementById('nj-other-fixed').value) || 0; var acW = parseFloat(document.getElementById('nj-ac').value) || 0; var heatW = parseFloat(document.getElementById('nj-heat').value) || 0; var evW = parseFloat(document.getElementById('nj-ev').value) || 0; var voltage = parseFloat(document.getElementById('nj-voltage').value);

var errors = []; if (isNaN(sqft) || sqft 20000) errors.push("Finished floor area must be between 100 and 20,000 sq ft."); if (rangW 0) { resultDiv.style.display = 'block'; resultDiv.innerHTML = 'Please fix the following:' + errors.map(function(e){ return ''; }).join('') + ''; return; }

// ============================================================ // NEC Article 220 Standard (Optional) Load Calculation // ============================================================

// --- STEP 1: General Lighting & Receptacle Load --- // NEC 220.12: 3 VA per sq ft for dwelling units var lightingVA = sqft * 3;

// --- STEP 2: Small Appliance & Laundry Branch Circuits --- // NEC 220.52(A): Two 20A small-appliance circuits = 2 x 1500 VA = 3000 VA // NEC 220.52(B): One 20A laundry circuit = 1500 VA var smallAppVA = 3000; var laundryVA = 1500;

// --- STEP 3: Total General Load before demand factor --- var generalLoadVA = lightingVA + smallAppVA + laundryVA;

// --- STEP 4: Apply NEC 220.42 Demand Factors to General Load --- // First 3000 VA @ 100% // Next 3001–120,000 VA @ 35% // Remainder > 120,000 VA @ 25% var demandGeneral = 0; if (generalLoadVA 0) fixedAppliances.push({name: "Water Heater", va: whW}); if (dwW > 0) fixedAppliances.push({name: "Dishwasher", va: dwW}); if (dispW > 0) fixedAppliances.push({name: "Disposal", va: dispW}); if (microW > 0) fixedAppliances.push({name: "Microwave", va: microW}); if (otherFixed > 0) fixedAppliances.push({name: "Other Fixed", va: otherFixed});

var fixedTotalVA = fixedAppliances.reduce(function(s, a){ return s + a.va; }, 0); var fixedDemandFactor = (fixedAppliances.length >= 4) ? 0.75 : 1.0; var demandFixed = fixedTotalVA * fixedDemandFactor;

// --- STEP 6: Electric Dryer (NEC 220.54) --- // Use nameplate or 5000 VA minimum, whichever is larger var dryerVA = Math.max(dryerW, dryerW > 0 ? 5000 : 0); // Single dryer: 100% demand var demandDryer = dryerVA;

// --- STEP 7: Electric Range / Cooking Equipment (NEC 220.55, Table 220.55) --- // For a single range rated 8.75 kW or more, use Column C of Table 220.55 // Simplified: single range demand per Table 220.55 Column C var demandRange = 0; if (rangW > 0) { var rangKW = rangW / 1000; if (rangKW = calcAmps && standardSizes[i] >= minServiceAmps) { requiredService = standardSizes[i]; break; } } if (calcAmps > 600) requiredService = Math.ceil(calcAmps / 100) * 100;

// NJ new construction: never less than 200A var njRequiredService = Math.max(requiredService, recommendedAmps);

// --- Build breakdown table --- var rows = [ ["General Lighting (3 VA × " + sqft + " sq ft)", lightingVA.toFixed(0), "100%", lightingVA.toFixed(0)], ["Small Appliance Circuits (2 × 1,500 VA)", smallAppVA.toFixed(0), "—", "—"], ["Laundry Circuit (1 × 1,500 VA)", laundryVA.toFixed(0), "—", "—"], ["General Load Subtotal", generalLoadVA.toFixed(0), "NEC 220.42", demandGeneral.toFixed(0)], ];

fixedAppliances.forEach(function(a) { rows.push([a.name, a.va.toFixed(0), (fixedDemandFactor*100).toFixed(0)+"%", (a.va * fixedDemandFactor).toFixed(0)]); });

if (dryerVA > 0) rows.push(["Electric Dryer (min 5,000 VA)", dryerVA.toFixed(0), "100%", demandDryer.toFixed(0)]); if (demandRange>0) rows.push(["Electric Range (Table 220.55)", rangW.toFixed(0), "NEC 220.55", demandRange.toFixed(0)]); if (hvacVA > 0) rows.push(["HVAC (larger of AC/Heat — noncoincident)", Math.max(acW,heatW).toFixed(0), "100%", hvacVA.toFixed(0)]); if (demandEV > 0) rows.push(["EV Charger", evW.toFixed(0), "100%", demandEV.toFixed(0)]);

var tableRows = rows.map(function(r){ return '' + r[0] + '' + r[1] + '' + r[2] + '' + r[3] + ''; }).join('');

var serviceColor = njRequiredService >= 200 ? '#2e7d32' : '#e65100';

resultDiv.style.display = 'block'; resultDiv.innerHTML = '### Load Calculation Results ' + '' + 'Load ItemConnected VADemand FactorDemand VA' + '' + tableRows + '' + '' + 'Total Calculated Load' + totalVA.toFixed(0) + ' VA' + 'Calculated Amperage (' + voltage + 'V)' + calcAmps.toFixed(1) + ' A' + '' + '' + '' + 'Minimum NEC Service Size: ' + requiredService + ' A

' + 'NJ Required Service Size (new construction): ' + njRequiredService + ' A

' + 'NJ DCA requires a minimum 200A service for new single-family residential construction.

' + '' + '' + '⚠ Note: This calculator provides an estimate per NEC Article 220 Standard Method. ' + 'All electrical work in New Jersey requires permits and inspections through your local municipality. ' + 'A licensed NJ electrical contractor must verify final service sizing.' + ''; }

#### Formula & Calculation Method

NEC Article 220 Standard Load Calculation (as adopted by NJ DCA):

#### Assumptions & References

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References

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