NEC 2026 Load Calculations: Article 120, the 2 VA Rule, and What Changed for Dwelling Services

A technical guide to the relocated and revised load-calculation article — the standard and optional methods worked end to end, the new branch-circuit count rule, EV charging, existing dwellings, multifamily buildings, and the errors circulating in early 2026 study material

Executive Summary

The 2026 edition of NFPA 70, the National Electrical Code, moved the load-calculation rules that every electrical designer, contractor, and plan reviewer has known for decades as Article 220 to a new home: Article 120, Branch-Circuit, Feeder, and Service Load Calculations. The section suffixes were preserved, so 220.82 is now 120.82 and Table 220.55 is now Table 120.55, but the move is more than housekeeping. It puts the calculation rules in Chapter 1 alongside the general requirements of Article 110, immediately ahead of the new Article 130 on power and energy management, and it arrived with substantive changes to the numbers.

Three of those changes affect nearly every dwelling calculation. First, the general lighting and general-use receptacle unit load for dwelling units fell from 3 VA to 2 VA per square foot in 120.41, a one-third reduction that reflects the disappearance of incandescent lighting and field data on what modern homes actually draw. Second, a new Section 120.13 requires the minimum number of general-purpose branch circuits to still be determined at 3 VA per square foot, so the smaller service load does not quietly translate into fewer circuits in the panel. Third, the optional method's 100 percent tier in 120.82(B) shrank from 10 kVA to 8 kVA, which partially offsets the lighting reduction for homes that use the optional path.



Around those headline items sit several smaller but consequential revisions: electric vehicle supply equipment is now calculated under 120.57 at the larger of nameplate or 7,200 VA, at 100 percent with no demand factor; power control systems are formally recognized in 120.7 so that a controlled setpoint, rather than connected nameplate, can enter the calculation; the clothes-dryer demand table in 120.54 was revised for small dryer counts; and the general rules in 120.5 clarify that the 125 percent continuous-load multiplier belongs to conductor and overcurrent-device sizing, not to the load calculation itself.

This guide walks through Article 120 the way a calculation actually flows: general rules, the general lighting group and its demand factor, appliances and cooking, heating and cooling, motors, and the assembly of a standard-method and an optional-method service calculation for the same house under both the 2023 and 2026 numbers. It then covers existing dwellings, multifamily buildings, neutral sizing, conductor selection, EV charging and load management, and closes with a correction section addressing errors we have found in early 2026 study material, a note on state adoption, and a 25-question FAQ.

1. Article 220 Becomes Article 120

NFPA's reorganization of the Code moved the load-calculation article from Chapter 2 (Wiring and Protection) to Chapter 1 (General). The reasoning is structural: load calculations are not a wiring method or a protection rule, they are a general requirement that every subsequent article consumes. Article 110 sets the general requirements for installations, Article 120 sets how loads are calculated, and the new Article 130 sets how power and energy management systems may control those loads. The three now read in sequence.



For practitioners the most important fact is that the section suffix survived the move. Anyone who can find 220.14(I) in the 2023 book can find 120.14(I) in the 2026 book. The table below maps the sections referenced most often in dwelling and light-commercial work.

2. The General Rules of Article 120

Part I of Article 120 sets the rules every downstream calculation depends on. Most are carried over from the 2023 text, but two additions matter.

2.1 Nominal voltages, rounding, and floor area (120.5)

Calculations are performed at nominal system voltages: 120, 120/240, 208Y/120, 240, 347, 480Y/277, 480, 600Y/347, and 600 volts. Where a calculation produces a fraction of an ampere, a fraction of 0.5 or larger is rounded up and a fraction below 0.5 may be dropped. Floor area is measured from the outside dimensions of the building, apartment, or other area involved; for dwelling units the area does not include open porches, garages, or unused or unfinished spaces that are not adaptable for future use. A basement that could become living space is counted; a crawl space is not.

The 2026 text adds a clarification practitioners have argued about for years: the 125 percent multiplier for continuous loads is not part of the load calculation. Continuous loads still drive conductor ampacity and overcurrent-device ratings through 210.19, 210.20, 215.2, 215.3, and 230.42, all of which remain in Chapter 2. But the calculated load that establishes the service size under Article 120 is the load itself. Keeping those two ideas apart prevents the double-counting that occurs when a designer applies 125 percent inside the calculation and then again when selecting conductors.

2.2 Noncoincident loads (120.6) and power control systems (120.7)

Where it is unlikely that two or more noncoincident loads will operate at the same time, only the largest load contributing to the total need be used. This is the general permission behind the heating-versus-cooling rule in 120.60 and the heat-pump provisions in the optional method.



New Section 120.7 formally recognizes power control systems, listed equipment that monitors current and actively limits it to a setpoint. Where such a system controls a load or group of loads, the setpoint may be used in the calculation in place of the connected nameplate, and the setpoint is treated as the calculated load for that group. This is the code hook that allows a 200 A service to accept two 48 A EV chargers, a heat pump, and an induction range without an upgrade, provided the control system is listed for the purpose and installed per Article 130 and, for EV charging, the energy-management provisions of Article 625.

3. The 2 VA Rule and the New Branch-Circuit Count

3.1 General lighting at 2 VA per square foot (120.41)

For dwelling units, the general lighting and general-use receptacle load for feeder and service calculations is now 2 VA per square foot of floor area. The 2023 value was 3 VA, a figure that had stood essentially unchanged since the era of incandescent lamps. Two things drove the change. Federal efficiency standards effectively removed general-service incandescent lamps from the market, moving residential lighting to LED sources that draw a fraction of the power. And measured data from a large sample of occupied U.S. homes, collected by the national laboratory community, showed median general lighting and receptacle density in the vicinity of 2.3 W per square foot. The Code-making panel adopted 2 VA as the new unit load for the service and feeder calculation.



In a dwelling the general-use receptacles are included in this unit load; they are not counted separately at 180 VA each. The 180 VA per receptacle rule in 120.14(I) applies to non-dwelling occupancies. The 2 VA figure flows into every dwelling method: the standard method in Part III, the optional one-family method in 120.82, the existing-dwelling method in 120.83, and the multifamily optional method in 120.84.

The reductions in the right-hand columns are connected-load reductions before the Table 120.42 demand factor. Because everything above the first 3,000 VA of the general lighting group is taken at 35 percent in the standard method, the effect on the final service current is smaller than the table suggests: roughly 0.35 × 2,400 VA ÷ 240 V, or about 3.5 A, for the 2,400 ft² house. Under the optional method, where the remainder above 8 kVA is taken at 40 percent, the effect is about 4 A for the same house.

3.2 Section 120.13: the circuit count stays at 3 VA per square foot



The panel recognized that if the same 2 VA figure were used to determine how many general-purpose branch circuits a dwelling needs, the circuit count would fall by a third and receptacle circuits would be more heavily loaded in practice. New Section 120.13 therefore requires the minimum number of 15 A or 20 A general-purpose branch circuits to be determined at 3 VA per square foot, independent of the 2 VA service calculation. The two figures answer two different questions for the same house.

4. Small-Appliance, Laundry, and the Lighting Demand Factor

Section 120.52 assigns 1,500 VA to each two-wire 20 A small-appliance branch circuit required by 210.11(C)(1), with a minimum of two, and 1,500 VA to the laundry branch circuit required by 210.11(C)(2). Where a dwelling has more than two small-appliance circuits, each is counted. Where a laundry receptacle is not required (for example, in a multifamily unit served by a common laundry that meets the conditions of 210.52(F)), the laundry load may be omitted.



These loads are added to the general lighting load and the sum is taken through Table 120.42. For dwelling units the demand factors are unchanged from the 2023 edition: the first 3,000 VA at 100 percent, from 3,001 to 120,000 VA at 35 percent, and the remainder above 120,000 VA at 25 percent. The demand factor recognizes that lighting, receptacle, kitchen countertop, and laundry loads do not peak simultaneously. It applies to this group only. Ranges, dryers, fixed appliances, heating, cooling, and EV charging each have their own rules and never pass through Table 120.42.

Two points deserve emphasis. The demand factor applies before the appliance, range, dryer, and HVAC loads are added, never to the whole-house total. And a demand factor never increases a load; where a reader sees a multiplier above 100 percent, it is the continuous-load rule for conductor sizing, which is a different concept living in a different article.

5. Fixed Appliances, Dryers, and Cooking Equipment

5.1 Fastened-in-place appliances (120.53)

Where four or more appliances fastened in place, other than ranges, clothes dryers, space-heating equipment, and air-conditioning equipment, are served by the same feeder or service in a one-family, two-family, or multifamily dwelling, a demand factor of 75 percent may be applied to their combined nameplate rating. Typical members of this group are the dishwasher, waste disposer, built-in microwave, water heater, well pump, sump pump, attic fan, and garage-door opener. With three or fewer, each is counted at 100 percent.

The group is defined by what is excluded. A range hood is a fastened-in-place appliance; a countertop microwave on a small-appliance circuit is not counted at all because it is already inside the 1,500 VA small-appliance allowance. Electric water heaters belong in this group even though they are often the largest single member.

5.2 Household clothes dryers (120.54)

Each household electric clothes dryer is counted at 5,000 VA or the nameplate rating, whichever is larger. Where a feeder or service supplies several dryers, as in a multifamily building or a laundry room, the demand factors of Table 120.54 apply. The 2026 edition revised the table for small dryer counts: the 2023 table held 100 percent through four dryers and stepped to 85 percent at five, whereas the 2026 table applies a reduced factor from the third dryer onward, reflecting the same diversity data that drove the lighting change. The table continues to decline with the number of dryers to a floor in the mid-20-percent range for very large counts. Because the small-count rows changed, designers should read the adopted 2026 table directly rather than relying on 2023 memory.



Where two or more single-phase dryers are supplied by a three-phase, four-wire feeder or service, the load is calculated on the basis of twice the maximum number connected between any two phases, exactly as for ranges.

5.3 Household cooking equipment (120.55 and Table 120.55)

Household electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances individually rated over 1¾ kW are calculated using Table 120.55 and its notes. Appliances at 1¾ kW or below are treated as ordinary appliance loads at nameplate. The table has three columns: Column A and Column B give percentage demand factors by number of appliances for units rated under 3½ kW and from 3½ to 8¾ kW respectively, and Column C gives a maximum demand in kW for appliances rated over 8¾ kW up to 12 kW. For a single range not over 12 kW, Column C yields 8 kW.

5.4 Range and dryer neutrals (120.61(B))

Because the heating elements of ranges and dryers operate line-to-line at 240 V, only the 120 V oven lights, controls, timers, and motors return on the neutral. Section 120.61(B) permits the feeder or service neutral for household ranges, wall ovens, cooktops, and dryers to be taken at 70 percent of the demand calculated above. That reduction is one of the two available for the neutral; the other, in 120.61(C), takes the portion of the unbalanced load above 200 A at 70 percent for loads other than nonlinear loads and three-wire single-phase or two-phase systems.

6. Heating, Air Conditioning, and Motor Loads

Fixed electric space heating enters the standard method at 100 percent of the total connected load under 120.51, with no demand factor unless the authority having jurisdiction grants one for a system with demonstrated diversity or duty cycle. Air-conditioning equipment enters at its rated load; for hermetic refrigerant motor-compressors the branch-circuit selection current or rated-load current from the nameplate governs per Article 440.

Section 120.60 then permits the smaller of two noncoincident loads to be omitted, and heating versus cooling is the textbook case. In the standard method the designer includes the larger of the space-heating load or the air-conditioning load and drops the other. For a heat pump with electric resistance supplemental heat, both the compressor and the strip heat are counted unless a control prevents simultaneous operation, in which case the smaller may be omitted.



Section 120.50 adds 25 percent of the largest motor load, per 430.24, on top of the other loads. In a dwelling the largest motor is usually the air-conditioning compressor. Where the compressor has been omitted under 120.60 because heating governs, the common practice, and the one Keentel follows, is to apply the 25 percent to the largest motor that remains in the calculation, typically the waste disposer, a well pump, or a pool pump. The adder is small, but omitting it entirely is a plan-review comment waiting to happen.

7. The Standard Method, End to End

Part III of Article 120 is the standard method for feeders and services. It applies to any occupancy, and for dwellings it is the method against which the optional methods are compared. The example below is a single-family dwelling with a full set of electric appliances and a Level 2 EV charger, worked under the 2026 numbers with the 2023 result alongside.

The lighting change trimmed 840 VA and about 3.5 A from this house, which did not move it across a service-size boundary. What did move it was the EV charger: without it the dwelling sits comfortably on a 200 A service under either edition, and with it the standard method calls for 225 A. This is the pattern Keentel sees on nearly every electrification project, and it is why the optional method and the power-control-system provisions matter far more in 2026 practice than the 2 VA headline.

7.1 Neutral load for the same dwelling (120.61)

The neutral is well below 200 A, so the additional 70 percent reduction of 120.61(C) does not apply. The grounded service conductor must still satisfy the minimum sizes of 250.24(D) tied to the grounding electrode conductor table, which for a 225 A service with 4/0 AWG copper or 300 kcmil aluminum ungrounded conductors typically requires a 2 AWG copper or 1/0 AWG aluminum grounded conductor regardless of the calculated neutral load.

7.2 Service conductors and the 83 percent rule

Service-entrance conductors must have an ampacity not less than the calculated load per 230.42(A), and the service disconnect for a one-family dwelling must be rated not less than 100 A, three-wire, per 230.79(C). For 120/240 V single-phase dwelling services and the main power feeder to a dwelling unit, 310.12 permits the ungrounded conductors to be sized at 83 percent of the service rating, which is the origin of the familiar 2/0 AWG copper or 4/0 AWG aluminum for a 200 A dwelling service and 4 AWG copper or 2 AWG aluminum for 100 A. The 83 percent allowance is a dwelling-specific recognition of load diversity and does not extend to feeders that serve only part of a dwelling's load or to non-dwelling occupancies.



Terminations are the controlling constraint in most residential equipment. Unless the equipment is listed and marked otherwise, conductors are selected from the 60°C column of Table 310.16 for circuits of 100 A or less and the 75°C column above 100 A, per 110.14(C). A 90°C conductor may be used for adjustment and correction factors but its ampacity is capped at the termination temperature rating.

8. The Optional Method for a One-Family Dwelling (120.82)

The optional method is available for a dwelling unit with a total connected load served by a single 120/240 V or 208Y/120 V three-wire set of service or feeder conductors with an ampacity of 100 A or greater. It replaces the separate demand factors of the standard method with a single general-load factor and a menu of heating and cooling options. Under the 2023 edition its general load took the first 10 kVA at 100 percent and the remainder at 40 percent. Under the 2026 edition the 100 percent tier is 8 kVA, with the remainder still at 40 percent.

8.1 The general load, 120.82(B)

The general load is the sum of: the general lighting and receptacle load at 2 VA per square foot; 1,500 VA for each two-wire 20 A small-appliance and laundry circuit; the nameplate rating of all appliances that are fastened in place, permanently connected, or on a specific circuit, including ranges, ovens, cooktops, dryers, water heaters, and similar equipment, and including motors not part of the heating or cooling equipment; and the nameplate rating of any motor and low-power-factor loads. Ranges and dryers go in at full nameplate here, not at the Table 120.55 or Table 120.54 values. The general load is then taken at 100 percent of the first 8 kVA and 40 percent of the remainder.

8.2 Heating and air-conditioning, 120.82(C)

The designer includes the largest of the following six items, not the sum: (1) 100 percent of the nameplate of the air conditioning and cooling; (2) 100 percent of the nameplate of heat-pump compressors where there is no supplemental heat; (3) 100 percent of the heat-pump compressor plus 65 percent of the supplemental electric heat, unless a control prevents simultaneous operation, in which case the supplemental heat is omitted; (4) 65 percent of the nameplate of central electric space heating where there are fewer than four separately controlled units; (5) 40 percent of the nameplate of four or more separately controlled electric space-heating units; and (6) 100 percent of the nameplate of electric thermal storage and similar systems where the expected load is continuous at full nameplate.



8.3 EV supply equipment in the optional method

Electric vehicle supply equipment is added at 100 percent of the larger of nameplate or 7,200 VA, consistent with 120.57. It is not part of the general load and does not receive the 40 percent factor. Where a listed energy-management system controls the EVSE, the controlled setpoint may be used per 120.7 and Article 625.

For this dwelling the optional method lands at 172 A against 218 A for the standard method, a difference of 46 A that keeps the house, EV charger included, on a 200 A service. The lighting reduction and the smaller 100 percent tier partly offset each other: the lighting change removed 2,400 VA from the general load (worth 960 VA after the 40 percent factor), while the tier change added 2,000 VA × 60 percent = 1,200 VA back. The net effect of the two 2026 changes on this house is close to zero under the optional method, and slightly favourable under the standard method.

9. Existing Dwellings: 120.83 and 120.87

Most of the load-calculation questions Keentel receives in 2026 are not about new construction. They are about whether an existing 100 A or 150 A service can accept a heat pump, an induction range, a battery system, or an EV charger. Article 120 offers two paths.

9.1 The existing-dwelling optional method (120.83)

Section 120.83 permits the total load of an existing dwelling unit to be calculated where additional loads are added, using the general load structure of the one-family optional method with its own demand factors and its own handling of heating and cooling. The 2026 edition reworked this section to distinguish between the loads that are already there and the specific classes of load being added, with different factors applied to added EV charging, added central resistance heating, and other added loads. Because the revised text departs from the familiar 2023 structure, designers should apply the adopted 2026 section directly rather than a 2023 template with the numbers changed.

9.2 Recorded maximum demand (120.87)

Section 120.87 permits the existing load to be established from the maximum demand recorded over one year, or, where a full year of data is not available, from a recording of at least 30 days that captures the peak season or is adjusted to reflect it. The existing demand is taken at 125 percent, and the new load is added at its calculated value. The 2026 text also addresses the credit that may be taken for loads that are being removed as part of the project, which is the practical case when a gas furnace and gas range are being replaced by electric equipment on a home that already has electric resistance backup.



Utility interval data, where the utility provides it, is the cleanest evidence for a 120.87 calculation. Where it is not available, a recording ammeter or power-quality logger on the service conductors for 30 days during the heating or cooling season is the usual approach. The recorded peak, times 1.25, plus the new load, is compared to the service rating.

10. Multifamily Dwellings, Two-Unit Services, and House Loads

The optional method in 120.84 applies to a multifamily dwelling of three or more units where no individual unit is supplied by more than one feeder, each unit has electric cooking equipment (or, where cooking is gas, is assumed to have an 8 kW electric range for the purpose of the calculation), and each unit has either electric space heating or air conditioning, or both. The connected load of all units combined, at 2 VA per square foot for lighting, 1,500 VA per small-appliance and laundry circuit, nameplate of all appliances, and the larger of heating or cooling in each unit, is taken through Table 120.84, whose demand factor falls with the number of units, from 45 percent at three to five units to 23 percent at 62 or more.



House loads, the corridor and site lighting, elevators, common laundry, domestic water pumps, fire pumps, and common-area HVAC, are not included in the Table 120.84 calculation. They are calculated by the standard method and added at their own values. Continuous house loads, such as 24-hour corridor lighting, drive conductor and overcurrent-device sizing at 125 percent under 215.2 and 215.3.

For two dwelling units on one service, 120.85 permits the calculation to be the larger of the sum of two individual 120.82 calculations or a 120.84 calculation for two units, rather than forcing the more conservative standard method. Individual unit feeders are calculated as single dwellings under 120.40 or 120.82; only the building service or the feeder to a group of units uses 120.84.

11. EV Charging and Load Management in the 2026 Code

Electric vehicle supply equipment is the load that most often breaks a dwelling calculation, and the 2026 edition addresses it from three directions. Section 120.57 sets the calculated load at the larger of the EVSE nameplate or 7,200 VA, at 100 percent, with no demand factor for multiple units unless a listed energy-management system is used. Section 120.7 recognizes power control systems so that a controlled setpoint may be used in place of nameplate. And Article 130, which absorbed the energy-management-system provisions formerly in Article 750 and added load-management requirements, together with the EV energy-management provisions of Article 625, establishes what qualifies as such a system.

The 7,200 VA floor deserves attention. A 30 A EVSE at 240 V has a nameplate of 7,200 VA, so the floor coincides with the smallest common Level 2 unit; a 16 A unit on a 20 A circuit (3,840 VA) is still calculated at 7,200 VA. The purpose is to size the service for the charger the homeowner will eventually install, not the one the builder specified. For a 40 A charger (9,600 VA) or a 48 A charger (11,520 VA), nameplate governs.

Where several EVSE share a feeder, as in a multifamily garage, the calculated load is the sum of the nameplates at 100 percent unless a listed energy-management system limits the aggregate, in which case the system's maximum setpoint is the load. For a 50-space garage, the difference between 50 × 11,520 VA (576 kVA) and a managed setpoint of, say, 150 kVA is the difference between a new utility service with a dedicated transformer and a feeder from the existing house switchboard. Keentel's multifamily and data-center practices treat managed EV charging as a design parameter to be settled before the service is sized, not after.

12. Where Early 2026 Study Material Goes Wrong

The 2026 edition has generated a wave of exam-prep guides, calculators, and question banks. Most repeat the 2 VA and 8 kVA headlines correctly. Several of the ones we have reviewed carry errors that would produce a wrong answer on a plan review. The following are the recurring ones.

13. Adoption Status and Transition Practice

NFPA issued the 2026 edition of NFPA 70 in the second half of 2025. Adoption is by state or local jurisdiction, and as of September 2026 the majority of jurisdictions remain on the 2023 or 2020 edition, with a small number having adopted the 2026 edition early in 2026 and others, including Texas at the state licensing level, adopting it effective in the second half of 2026. Several large states adopt on a fixed multi-year cycle that will not reach the 2026 edition until 2027 or 2028, and some jurisdictions adopt with amendments that modify or delete specific sections.



For projects that straddle the transition, Keentel recommends three practices. Confirm the edition and any local amendments in writing with the authority having jurisdiction before the calculation is issued, because the 2 VA rule alone can change a service size. Carry dual section citations on calculation sheets until the jurisdiction has adopted the 2026 edition. And where a project permitted under the 2023 edition will be inspected after the 2026 edition takes effect, confirm which edition governs the inspection; most jurisdictions apply the edition in force at permit application, but not all.

14. How Keentel Engineering Can Help

Keentel Engineering is a Florida-registered engineering firm with offices in Tampa, Austin, Sacramento, and Baltimore, providing electrical power systems engineering from 4 kV to 765 kV and electrical-led MEP design for buildings. Our load-calculation and service-design work sits within the MEP Engineering Services and Data Center Power Engineering service lines.

Keentel seals the electrical design. Mechanical and plumbing design and sealing are performed by licensed specialists whom Keentel coordinates, and civil and structural work is coordinated with the appropriate registered professionals.

To discuss a project, contact Keentel Engineering at (813) 389-7871 or contact@keentelengineering.com, or schedule a 15-minute call at calendly.com/keentel-engineering/15min.

References and Further Reading

Primary sources are listed first. Links were current at publication in September 2026.

Codes and standards

• NFPA 70, National Electrical Code, 2026 edition. National Fire Protection Association, Quincy, MA, 2025. Article 120 (Branch-Circuit, Feeder, and Service Load Calculations), Article 130 (Power and Energy Management Systems), Articles 210, 215, 230, 310, 424, 430, 440, and 625. www.nfpa.org/70
• NFPA 70, National Electrical Code, 2023 edition. National Fire Protection Association, 2022. Article 220 and Article 750, used for the comparison figures in this guide.
• NFPA 70 2026 edition, First Draft Report and Second Draft Report, Code-Making Panel 2 (load calculations) and the Correlating Committee, 2024–2025, for the substantiation of the 2 VA unit load, new Section 120.13, and the relocation of Article 220. Available through the NFPA document information pages.

Technical basis

• Lawrence Berkeley National Laboratory, residential electrical load and service-capacity studies underpinning the 2 VA per square foot substantiation, including field data on general lighting and receptacle demand density in occupied U.S. dwellings, 2022–2024. eta.lbl.gov
• U.S. Department of Energy, energy conservation standards for general service lamps, 10 CFR Part 430, effective 2023, the regulatory driver for the transition of residential lighting to LED sources.

Industry commentary



• "Changes to Dwelling Unit Calculations in the 2026 NEC," EC&M, Endeavor Business Media, 2026. www.ecmweb.com
• State adoption tracking: NFPA NEC Adoption Maps and the individual state licensing-board and building-code-council notices, consulted September 2026.
  

Frequently Asked Questions

Disclaimer

This document is published by Keentel Engineering for general technical information and educational purposes. It is not a substitute for the adopted text of NFPA 70, the National Electrical Code, as amended and enforced by the authority having jurisdiction for a specific project, and it does not constitute engineering services, a code interpretation, or a sealed design for any project. Section numbers, table values, and demand factors cited are stated to the best of Keentel's knowledge of the 2026 edition as published; readers must verify every value against the edition and amendments adopted in their jurisdiction before relying on it.



The worked examples are illustrative. They do not describe any specific client, site, project, product, utility, or authority having jurisdiction, and the equipment ratings used are representative values chosen to demonstrate the method. Actual calculations must use the nameplate data, floor areas, and utility and jurisdictional requirements of the project concerned.

Statements about state and local adoption of the 2026 edition reflect publicly available information as of September 2026 and change frequently. Confirm adoption status and local amendments with the authority having jurisdiction.

Keentel Engineering provides electrical engineering services. Mechanical and plumbing design and sealing are performed by licensed specialists coordinated by Keentel. Civil, structural, and geotechnical work is coordinated with the appropriate registered professionals. Nothing in this document should be read as implying that Keentel holds licensure in any discipline other than those it states.

National Electrical Code and NEC are registered trademarks of the National Fire Protection Association, Quincy, MA. Keentel Engineering is not affiliated with, endorsed by, or sponsored by the National Fire Protection Association, Lawrence Berkeley National Laboratory, the U.S. Department of Energy, any publisher named in the references, or any manufacturer of the equipment types discussed. Product and organization names are used for identification only.

Keentel Engineering makes no warranty, express or implied, as to the accuracy, completeness, or fitness for any purpose of the information in this document, and accepts no liability for any loss arising from its use. Readers requiring a calculation for a specific project should engage a licensed professional engineer in the project jurisdiction.

State of Florida — Registry No. 36853, KEENTEL LLC, DBA: KEENTEL ENGINEERING. Copyright 1995–2026 Keentel Engineering. All Rights Reserved. This document is original work of Keentel Engineering and may not be reproduced, distributed, or adapted without written permission, except for brief quotation with attribution.