Load calculations wrapper
Why you care (60 seconds)
Load calculations drive conductor sizing, OCPD selection, and service capacity. Getting the demand right avoids oversized gear or dangerous undersizing.
Where people lose time
- Mixing connected load with calculated demand load.
- Using the wrong demand factors for general lighting.
- Forgetting to include fixed appliances or special loads.
This is
The rule in plain language
Calculate the expected electrical demand using code-defined load values and applicable demand factors, not just the sum of nameplates.
When it applies
Whenever sizing feeders, services, or equipment based on total load.
What you must do (checklist)
- List each load category and its calculation basis.
- Apply demand factors where allowed and required.
- Document assumptions for continuous and non-continuous loads.
- Keep calculation steps reproducible for inspection review.
Quick examples
- Apply demand factors to general lighting instead of full connected load.
- Separate fixed appliances from general lighting when calculating demand.
This is not
Common misreads
- Treating a connected load list as the final design load.
- Assuming every load uses the same demand factor.
What it doesn't cover
- Detailed calculations for specialized occupancies.
- Utility service sizing requirements beyond the NEC.
False friends
- A large nameplate does not always equal calculated demand.
Exceptions & edge cases
- Some occupancies require stricter calculation methods.
- Optional calculation methods may have prerequisites.
Cross-references (NEC map)
- Primary: 220.14, 220.42
- Secondary: 220.40
Exam traps
- Confusing demand factors with diversity assumptions.
- Omitting a load category that must be included.
Field notes
- Use a consistent spreadsheet template for calculations.
- Save calculation snapshots for plan review and inspection.
AHJ / Local amendments notes (placeholder)
- Add local amendments or interpretations here.
Revision notes
- Draft wrapper created for load calculation fundamentals.