NEC Article 120 Load Calculation Lookup
Article 120 establishes the calculated load basis for branch circuits, feeders, and services. Treat it as the upstream calculation checkpoint before equipment sizing, conductor ampacity, overcurrent protection, voltage drop, grounding, and raceway review.
| Field Item | NEC Reference | Field Meaning |
|---|---|---|
| Article relocation | 2026 NEC Article 120 / former Article 220 | Load calculations moved from the long-used Article 220 location into Article 120 for the 2026 NEC structure. |
| Branch-circuit, feeder, and service scope | NEC Article 120 | The calculated load is established before downstream breaker, wire, ampacity, voltage-drop, grounding, and raceway checks. |
| Dwelling service and feeder load basis | NEC Article 120 dwelling context | Use the adopted NEC calculation path for dwelling service and feeder sizing. Do not reuse older Article 220 assumptions without checking the adopted code cycle. |
| 2 VA vs 3 VA distinction | NEC Article 120 dwelling load context | Keep service/feeder load calculation separate from branch-circuit planning. Mixing the two can produce the wrong load basis. |
| Standard vs optional method | NEC Article 120 calculation methods | Select the proper method for the occupancy and calculation purpose. Review NEC 220.82 Optional Method Load Calculation before relying on optional-method demand treatment. |
| Small-appliance and laundry reminders | NEC Article 120 dwelling provisions | Required dwelling loads may be missed when a field estimate starts only with square footage. |
| HVAC noncoincident load review | NEC Article 120 heating and cooling context | Heating and cooling loads are not always added together at full value. The applicable NEC method controls the load included. |
| Downstream checks | NEC 110.14(C) Terminal Temperature Limits, NEC 310.16 Ampacity Table, NEC 240.4(B) Next-Size-Up Rule, NEC 250.122 Equipment Grounding Conductor Sizing, Chapter 9, NEC 625 | A calculated load does not finish conductor, breaker, grounding, EVSE, voltage-drop, or raceway review. |
2026 Reorganization
Article 120 vs Former Article 220
For years, electricians relied on Article 220 for load-calculation rules. With the 2026 NEC reorganization, branch-circuit, feeder, and service load calculations are now organized under Article 120.
Older plans, exam references, inspection comments, and adopted code cycles may still use Article 220 language. This page uses the current Article 120 designation while keeping the former Article 220 reference visible for electricians working from older plans, code-cycle references, or adopted-code language.
Field translation: On a 2026 NEC job, references to an “Article 220 load calc” should be checked against the current Article 120 location and the jurisdiction’s adopted code cycle.
DWELLING LOAD BASIS
2 VA vs 3 VA Load Basis
The 2026 dwelling load calculation change creates a common field trap: service and feeder load calculation must be kept separate from branch-circuit quantity and layout planning.
Service and feeder load basis
Use the adopted NEC Article 120 dwelling calculation path for service and feeder load basis. Do not carry older square-footage assumptions forward without checking the code cycle.
Branch-circuit planning context
Branch-circuit and receptacle planning can still involve a different load basis than the service or feeder calculation. Keep the calculation purpose clear before using the result downstream.
Field warning: The mistake is not the number by itself. The mistake is using the right number for the wrong purpose.
METHOD SELECTION
Standard vs Optional Method
Standard method
Use the standard calculation path when the occupancy, load category, or project scope requires a category-by-category load buildup. Avoid borrowing demand treatment from another method.
Optional dwelling method
Common for dwelling service and feeder screening when the installation qualifies. Use it as a complete method, not as a menu of demand factors to mix into another calculation path.
FIELD WORKFLOW
Load-Basis Workflow
Confirm the code cycle. Verify whether the jurisdiction is using 2026 Article 120 or an older Article 220 adoption.
Pick the method. Choose the correct dwelling, non-dwelling, service, feeder, or branch-circuit path.
Build the load basis. Include required load categories before applying any permitted demand treatment.
Keep purposes separate. Do not mix service/feeder calculation logic with branch-circuit planning checks.
Send downstream. Use the calculated load as input for breaker, wire, ampacity, EV, and voltage-drop review.
TRUST BOUNDARY
Load Calculation Boundary
Article 120 establishes the calculated load. That value is only the starting basis for equipment and conductor decisions.
Breaker sizing still needs overcurrent rules, continuous-load review, equipment markings, and listed-device conditions. Conductor sizing still needs ampacity tables, terminal temperature limits, insulation context, adjustment factors, voltage-drop review, equipment grounding conductor sizing, and raceway fill.
Field warning: Do not mix service/feeder load basis, branch-circuit planning, and downstream breaker or conductor sizing checks. A calculated load is not breaker approval, conductor approval, EVSE approval, or AHJ acceptance.
Workflow Order
- 1. Load basis
- 2. Breaker/OCPD screen
- 3. Wire and ampacity
- 4. Voltage drop
- 5. Grounding and raceway
FIELD CHECKS
Dwelling Load Field Checks
Do not mix optional-method and standard-method pieces. Pick the applicable NEC path before applying demand treatment.
Do not treat square footage as the full service load. Required small-appliance, laundry, fixed appliance, HVAC, EVSE, range, dryer, and other loads may need separate handling.
Keep heating and cooling logic separate. The applicable NEC method controls how noncoincident heating and cooling loads are counted.
Do not use service load as EV branch-circuit approval. EVSE still needs NEC 625, continuous-load sizing, terminal limits, conductor ampacity, and manufacturer instructions.
Confirm local service rules. Utility requirements, local amendments, and AHJ expectations can change the accepted service calculation basis.
Field Example
Load Basis Before Equipment Sizing
A dwelling load calculation result is not the same thing as a finished breaker, conductor, or service-equipment approval. First establish the adopted Article 120 load basis, then pass that result into the downstream sizing checks.
- Load calculation: identify the applicable standard, optional, EVSE, appliance, or equipment load path.
- Downstream checks: use the calculated load for breaker sizing, wire sizing, ampacity, voltage drop, grounding, and raceway review.
- Boundary: manufacturer instructions, local amendments, service equipment ratings, and AHJ interpretation still control final field use.
Calculator Use
TradeHub Calculator Application
Use Article 120 as the upstream load-basis checkpoint before selecting breakers, conductors, EV circuit sizing, voltage-drop screening, and raceway checks.
Related TradeHub Calculators
RELATED REFERENCES
Related NEC Field References
SOURCE SCOPE
Source Alignment and Use Scope
This field reference is based on NEC Article 120 branch-circuit, feeder, and service load calculation structure, former Article 220 transition context, dwelling load calculation workflow, and related TradeHub source alignment records. It is intended for screening and planning only before using TradeHub electrical calculators. It does not reproduce proprietary NEC text, approve breakers, approve conductors, approve EVSE wiring, approve grounding, approve raceway fill, replace the adopted NEC, override local amendments, replace utility service requirements, equipment markings, manufacturer instructions, engineered service design documents, or AHJ review. Review the TradeHub Code Citation & Source Log for source alignment records and the TradeHub Methodology page for how field references are scoped.
FIELD FAQ
Load Calculation FAQ
Did NEC Article 220 become Article 120 in the 2026 NEC?
Yes. In the 2026 NEC, branch-circuit, feeder, and service load calculation rules were reorganized from Article 220 into Article 120. Older adopted code cycles, plans, and inspection habits may still use Article 220 language, so the adopted code cycle must be confirmed.
Is a load calculation the same as breaker sizing?
No. The load calculation establishes the load basis. Breaker sizing still needs overcurrent rules, continuous-load rules, equipment markings, conductor ampacity, terminal temperature limits, and local code review.
Can a dwelling load calculation approve EV charger wiring?
No. A dwelling load calculation can help evaluate service capacity, but EVSE branch-circuit sizing still needs NEC 625, continuous-load sizing, conductor ampacity, terminal limits, manufacturer instructions, and AHJ review.