Feeder & Service Load Chart — NEC 220 Demand Factors

Feeder & Service Load Chart — NEC 220 Demand Factors featured image

NEC Article 220 demand-factor reference for feeder and service planning — general lighting, receptacle, motor, and common continuous-load factors. Apply demand before converting VA to amps at system voltage.

How to Use This Chart

Apply demand factors to connected load before converting VA to amps at system voltage. Full interactive takeoff: feeder/service load calculator. Walkthrough: how to size a feeder or service entrance.

Article 220 builds calculated load in layers: connected loads → demand factors → largest motor contribution → continuous-load adjustment → neutral load where applicable. This chart covers the most common non-dwelling factors; dwelling units use optional methods in 220.82 or 220.83 — use the residential load calculator for those.

Order of operations Demand first on applicable loads, then add motor contributions per 220.50, then apply 125% to continuous portions before comparing to conductor ampacity.

General Lighting Demand (NEC 220.42)

Portion of lighting load Demand factor
First 3,000 VA 100%
3,001–120,000 VA 35%
Remainder over 120,000 VA 25%

General lighting load is often assigned by occupancy (Table 220.12) — e.g., office 1 VA/ft² — then reduced by these demand factors for feeder and service conductors. Branch-circuit conductors upstream of the demand point may still be sized to connected load per 210.

Receptacle Loads — Non-Dwelling (220.44 / Table 220.44)

Portion of receptacle load Demand factor
First 10 kVA (10,000 VA) 100%
Remainder over 10 kVA 50%

Applies to receptacle loads calculated per 220.14(I) and (K). Fixed equipment with dedicated circuits is usually calculated at nameplate, not through this table.

Other Common Demand Factors

Load type Code ref Demand factor
Household electric range (each) Table 220.55 Per column — not 100% of nameplate
Commercial cooking 220.56 65% if thermostatic control; 100% otherwise
Fixed electric space heating 220.51 100% (no reduction)
Noncoincident loads (heat vs AC) 220.60 Larger of the two — not sum
Largest motor 220.50 125% of largest motor FLA added
Remaining motors 430.24 / 430.26 Sum FLA at 100%; apply 430.26 if applicable
EVSE (general) 625.41 100% unless 625.42 load management applies

Continuous vs Noncontinuous

Load type Feeder/service conductor & OCPD
Continuous (3+ hours) Size at 125% of continuous (215.2 / 230.42)
Noncontinuous 100% of noncontinuous
Mixed Noncontinuous + 125% of continuous

Lighting in many commercial occupancies runs 3+ hours — treat as continuous unless you can document otherwise. Data racks, ventilation, and process loads are almost always continuous. Receptacle loads are often noncontinuous unless dedicated to continuous equipment.

Appliance note A 20 A receptacle circuit is not automatically 1,920 VA continuous — but the equipment plugged in may be. Size the feeder for what actually runs continuously, not the breaker label alone.

VA → Amps at Common Voltages

Demand VA 120/240 1φ (A) 120/208 3φ (A) 277/480 3φ (A) 120/240 3φ (A)
5,000 20.8 13.9 6.0 12.0
10,000 41.7 27.8 12.0 24.1
15,000 62.5 41.6 18.0 36.1
25,000 104.2 69.4 30.1 60.1
50,000 208.3 138.8 60.1 120.3
75,000 312.5 208.2 90.2 180.4
100,000 416.7 277.6 120.3 240.6
150,000 625.0 416.4 180.4 360.8
200,000 833.3 555.2 240.6 481.1
300,000 1250.0 832.7 360.8 721.7
400,000 1666.7 1110.3 481.1 962.3

1φ amps = VA ÷ 240. 3φ amps = VA ÷ (√3 × VLL). 120/240 3φ (high-leg delta) line current uses 240 V line-to-line for the formula when loading is balanced across phases.

Worked Example — Small Office Service

Given: 3,000 ft² office, 120/208 V 3φ service.

  • General lighting: 3,000 ft² × 1 VA/ft² = 3,000 VA → 100% = 3,000 VA
  • Receptacles: 3,000 ft² × 1 VA/ft² = 3,000 VA → 100% (under 10 kVA) = 3,000 VA
  • HVAC motor: 15 A × 208 V × √3 = 5,402 VA → 125% largest motor add = 6,753 VA (per 220.50)
  • Water heater 4,500 VA — noncontinuous → 4,500 VA

Total calculated load ≈ 17,253 VA (simplified — actual takeoff may combine lighting/receptacle per 220.42/220.44 separately on larger buildings).

Amps at 208 V 3φ: 17,253 ÷ (1.732 × 208) = 47.9 A. Size service conductors and OCPD to next standard rating above calculated load after continuous adjustments.

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