Verbatim code text, the full demand-factor tier table by occupancy, the tier-boundary math, worked examples, and a free in-browser calculator. Last updated 2026-08-29 (written for PanelWright v1.14).
Runs in your browser. No account, no install, data never leaves your machine. The lighting card sits below the other NEC load cards on the main page.
For the general lighting load (general illumination) on a feeder or service under the standard method, you take the total connected lighting VA and apply Table 220.42’s demand factors tier by tier — each factor applies only to the slice of load that falls inside that tier — and the demand is the sum of those tier contributions. The factors are set by the occupancy type (dwelling, hospital, hotel/motel, warehouse, or all others). The demand factors do not apply when counting the number of lighting branch circuits, and they do not apply under the 220.82 optional method.
The whole rule is short because the substance lives in the table. Two scope sentences matter in practice: the factors apply to the general illumination portion of the branch-circuit load (not receptacles, cooking, dryers, etc.), and they may not be used to reduce the number of branch circuits you must install.
Demand factors for general lighting load, by occupancy type (2014–2023 editions). Each factor applies only to the portion of the connected lighting load inside that tier:
| Type of occupancy | Portion of lighting load (VA) | Demand factor (%) |
|---|---|---|
| Dwelling units | First 3,000 or less | 100 |
| From 3,001 to 120,000 | 35 | |
| Remainder over 120,000 | 25 | |
| Hospitals* | First 50,000 or less | 40 |
| Remainder over 50,000 | 20 | |
| Hotels and motels, incl. apartment houses without provision for cooking by tenants* | First 20,000 or less | 50 |
| From 20,001 to 100,000 | 40 | |
| Remainder over 100,000 | 30 | |
| Warehouses (storage) | First 12,500 or less | 100 |
| Remainder over 12,500 | 50 | |
| All others | Total volt-amperes | 100 |
*The demand factors of this table shall not apply to the calculated load of feeders or services supplying areas in hospitals, hotels, and motels where the entire lighting is likely to be used at one time, as in operating rooms, ballrooms, or dining rooms.
Table 220.42 is a tiered table, not a single lookup. You split the connected lighting load into the tier bands and multiply each band by its own factor, then add the results. The most common error is applying one factor to the whole load. Example for a 150,000 VA dwelling lighting load: 3,000 @ 100% = 3,000; the 117,000 between 3,000 and 120,000 @ 35% = 40,950; the 30,000 over 120,000 @ 25% = 7,500; total demand = 51,450 VA — not 150,000 × 35%.
| Occupancy | Connected load (VA) | Boundary behavior | Demand (VA) |
|---|---|---|---|
| Dwelling | 3,001 | one VA above the first tier → 3,000 @ 100% + 1 @ 35% | 3,000.35 |
| Dwelling | 120,000 | exactly at the top of the middle tier → 25% band is 0 | 43,950 |
| Dwelling | 120,001 | one VA over → 25% band starts at 0.25 | 43,950.25 |
| Hospital | 50,000 | exactly at the tier seam → 20% band is 0 | 20,000 |
| Hotel/motel | 20,000 | exactly at the tier seam → 40% band is 0 | 10,000 |
| Warehouse | 12,500 | exactly at the tier seam → 50% band is 0 | 12,500 |
At each seam the demand is continuous (no jump) — crossing a boundary changes which factor applies to the next VA, not the VA at the boundary. PanelWright walks the tiers with cumulative upper bounds, so every seam is handled exactly, and these values are pinned by the public test suite.
| Occupancy | Connected lighting load | Tier math | Demand |
|---|---|---|---|
| Dwelling | 150,000 VA | 3,000 @100% + 117,000 @35% + 30,000 @25% | 51,450 VA |
| Dwelling | 50,000 VA | 3,000 @100% + 47,000 @35% | 19,450 VA |
| Hospital | 100,000 VA | 50,000 @40% + 50,000 @20% | 30,000 VA |
| Hospital | 50,000 VA | 50,000 @40% (tier boundary) | 20,000 VA |
| Hotel/motel | 100,000 VA | 20,000 @50% + 80,000 @40% | 42,000 VA |
| Hotel/motel | 130,000 VA | 20,000 @50% + 80,000 @40% + 30,000 @30% | 51,000 VA |
| Warehouse | 12,500 VA | 12,500 @100% (tier boundary) | 12,500 VA |
| All others | 50,000 VA | 50,000 @100% (no diversity) | 50,000 VA |
Every number above is computed by the real shipped lightingDemand22042() core and is an assertion in the tool’s public test suite (test/run_tests.js in the public repo). The dwelling 150,000 → 51,450, hotel 100,000 → 42,000, hotel 130,000 → 51,000, and warehouse 12,500 → 12,500 cases were the cross-check vectors when the card was built (Session 9), and the tier-boundary cases (3,001 / 120,000 / 120,001 / 50,000 / 20,000 / 12,500) are added to the suite alongside this article.
The verbatim NFPA 70 2014 Article 220 PDF (the table read directly from the print layout, clean text layer) is unambiguous, and it is what PanelWright implements. One 2020-edition OCR text source (the on-disk full-code scan) rendered the hotel/motel row as “60 / 50 / 35” instead of “50 / 40 / 30” — but that same OCR row also mangles the “100,000” tier boundary into “J00,000” / “l00,000,” the signature of the digit-garbling corruption class this project has hit before. Three independent live sources (VoltageLab, a 2026 code reference, and ecalpro) all state the hotel/motel factors as 20,000 @ 50%, 20,001–100,000 @ 40%, remainder @ 30% — matching the verbatim 2014 table and the shipped tool. If a free source prints a different hotel factor, the verbatim table wins.
Open the PanelWright 220.42 card →
Enter the total lighting VA and the occupancy type (dwelling, hospital, hotel/motel, warehouse, all others), and the card shows each tier’s contribution, the total demand, and the implied square footage at the 3 VA/sq ft dwelling unit value (a design-basis helper, not a code number) — then rolls it into the CSV export and the branded PDF project report. The same page also covers 220.82 (optional dwelling service load), 220.55 cooking, 220.54 dryers, 220.53 fixed appliances, 220.56 commercial kitchen, 220.61 neutral, Table 310.16 conductor picks, voltage drop (Ch. 9), phase balancing, and breaker sizing.