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NFPA 70 workflowUser-verified demand loadsBounded worksheet

Commercial Demand-Load
Summary Worksheet

Sum load-category results already calculated under the adopted NEC method, then convert total volt-amperes to line current. This worksheet does not choose demand factors, calculate branch or feeder loads, or size a service.

Who it's for: electrical engineers and contractors totaling already-calculated commercial load categories at construction documents.

Verified demand-load schedule
VA → A

How to use this calculator

1
Select the governing method first
Use the adopted NFPA 70 edition and applicable other articles to determine the calculation path and every load category outside this worksheet.
2
Enter demand-adjusted category totals
Enter final VA after the qualified designer has applied relevant unit loads, demand factors, noncoincident-load rules, continuous-load treatment, motor provisions, and equipment rules.
3
Enter line voltage and phase
Use line-to-line voltage for the balanced three-phase conversion. The worksheet divides VA by V for single-phase or by V × √3 for three-phase.
4
Use the result only as a schedule cross-check
The output is a sum and current conversion, not a service or feeder design.

The formula

Total entered demand VA = sum of the entered category demand loads.
Single-phase current = VA ÷ line voltage.
Balanced three-phase current = VA ÷ (line voltage × √3).

No NEC demand factor, load inclusion rule, or standard equipment rating is embedded.

Worked example

Example
If verified category demand loads total 79,400 VA, the arithmetic current at 208 V three-phase is 79,400 ÷ (208 × √3) = 220.4 A. That does not by itself establish a service rating.

When this estimate will be off

  • Does not determine which Article 220 method applies or whether another NEC article modifies or supplements it.
  • Does not calculate lighting, receptacle, appliance, heating, cooling, motor, EV, health-care, marina, farm, neutral, continuous, nonlinear, or other project loads.
  • The three-phase conversion assumes the entered total represents a balanced apparent load; phase imbalance and neutral loading require separate analysis.
  • Does not select service, feeder, conductor, overcurrent protection, equipment, utility transformer, fault rating, or standard size.
  • Confirm the adopted edition, local amendments, utility requirements, equipment listings, and authority having jurisdiction.

Frequently asked questions

A common mistake: Does not determine which Article 220 method applies or whether another NEC article modifies or supplements it.

Those factors and their applicability depend on the adopted edition, occupancy, calculation scope, load classification, and selected method. Enter the verified demand-adjusted category result instead.

No. It is only arithmetic from entered demand VA and voltage. Service, feeder, conductor, and protection selection require the complete adopted-code and utility analysis.

The incomplete embedded Article 220 approximation and standard-size recommendation were removed. The route now exposes only a bounded load-schedule sum and phase-current conversion.

Sources

  • NFPA LiNK — NFPA 70 (NEC) 2023 — licensed edition containing the Article 220 branch-circuit, feeder, and service load-calculation framework
  • NFPA 70 Table 220.3 and applicable Chapters 4–7 — specific-purpose calculations can amend or supplement Article 220
  • NFPA Article 220 public development record — official committee-development material showing Article 220 scope, Table 220.3 dependencies, and Annex D context

This free Commercial Electrical Load Calculator is built and maintained by DataDrivenAEC, using the relevant codes and standards. It does not substitute for professional judgment.