Begin with eligibility
Part IV of 2026 NEC Article 120 contains optional feeder and service methods for qualifying dwelling units, existing dwelling additions and certain multifamily arrangements. Verify dwelling configuration, supply characteristics, unit count and all method conditions before entering a demand table. If eligibility is not established, use the applicable standard method.
Separate the load groups
Build a general-load subtotal, then handle heating and cooling according to the method’s operating assumptions. Check heat-pump supplemental heat and electric resistance heat instead of assuming all heating and cooling are noncoincident. Treat EVSE under the selected method’s rule and identify any power control system separately.
Existing dwellings need a before-and-after view
For an addition, record existing and proposed loads independently. Confirm old equipment ratings in the field where records are incomplete. A comparison between permitted methods should display the inputs and result of each, so a reviewer can see why the selected method fits.
Field check
- Confirm the unit configuration and electrical supply used by the proposed optional method.
- Verify nameplates for HVAC, supplemental heat, appliances and EVSE.
- Compare existing and proposed loads; document any control or noncoincident claim.
Show on drawings
Put an eligibility statement, load-by-category worksheet, equipment ratings and method comparison on the calculation sheets. Coordinate unit count and common loads with architectural and MEP schedules. For measured existing demand as a separate route, see #033.
Code basis and applicability
Educational reference to the 2026 NEC Sections 120.80–120.85. Check the complete NFPA 70 text, the locally adopted edition and amendments, the authority having jurisdiction, and selected equipment instructions before project use. This page is not a project-specific load calculation or professional code determination.