Electrical Panel Strategy

Table 1 maps the parts to the three components. Subsections that cover one component carry an Applies to tag. An Informs tag marks the subsections behind each decision above.

1 · Demand: why a service is smaller than its connected load

Bottom line. A house's connected nameplate load is far larger than any current it draws, because loads cycle and rarely peak together; the code's demand factors encode that, and all-electric conversion adds the loads that do peak together.

Calculated load is connected load scaled by coincidence

P_i(t) demand of load i at time t · F_c coincidence factor, 0 to 1

the peak of the whole house divided by the sum of each load's own peak.

The reference all-electric house in Table 2 has 60,320 VA connected, 251 A at 240 V. Its 220.83(B) calculated load, worked in Part 2, is 151 A, so the code treats about 60% of the nameplate as coincident (Figure 1). Article 220's "first 8 kVA at 100%, the rest at 40%" is a two-step approximation of that factor: the first increment of load is nearly always present, and each further increment is less likely to coincide with the rest.

Two kinds of load do not average out. Space heating and cooling run for hours at the design condition, in the evening when the rest of the house is busy; an EV charger draws its full current for hours. 220.83(B) takes heating and cooling equipment at 100% of nameplate, and 220.57 gives a charger a floor of 7,200 VA, so a heat pump in place of a gas furnace adds load at full value rather than at 40%.

Measured peaks sit well below calculated loads. Silicon Valley Clean Energy cites a study of more than 22,000 California homes in which 86% peaked below 50 A, and Peninsula Clean Energy found that 99% of all-electric single-family homes in its data never drew more than 100 A. The code's calculation is a defined worst case, not a forecast; the methods in Parts 3 and 4 exist to let measured behavior or a control device replace it.

The reference all-electric load stack

Informs D5

Table 2 lists the loads used throughout this guide. They follow the project premises: an air-to-water heat pump sized for the reference load in HVAC · Capacity and sizing, supplementary resistance heat below the Title 24 cap of 2.7 kW per nominal ton, whose application to air-to-water systems is confirmed at plan check (HVAC · Backup heat), a dedicated heat pump water heater with a 4.5 kW element, induction cooking and one Level 2 charger. Values are class-typical; none is a product selection.

For a motor-driven appliance the nameplate gives a minimum circuit ampacity (MCA) and a maximum overcurrent protection (MOCP) rather than one current; MCA sizes the conductors. A dryer or water heater with a heat pump instead of an element, or a shared heat pump that also makes hot water (HVAC · Shared or dedicated), removes most of its row.

2 · Calculated load: the code's methods

Bottom line. The same house yields legal results from about 126 A to 207 A depending on the method and on two open questions, the charger's demand factor and the backup interlock; no reading fits a 100 A service and most fit 200 A.

The methods differ in question, evidence or demand factor

Informs D1

Article 220 gives a standard method and optional methods for dwellings; Parts 3 and 4 add measured demand and load management. They are not approximations of one another (Table 3). The standard and optional methods model a defined worst case from nameplates; measured demand replaces part of the model with data; load management changes the house's behavior and calculates on the changed behavior.

220.83(B) takes space conditioning at full nameplate

Informs D1

Σ_other general lighting at 3 VA/sf, small-appliance and laundry circuits, and appliances at nameplate, VA · Σ_space conditioning heating or cooling equipment at 100%, VA

the first 8 kVA of ordinary load counts in full and the rest at 40%; heating and cooling count in full on top.

220.83 applies to an existing dwelling on a 120/240 V or 208Y/120 V three-wire service receiving added load. Paragraph (A) applies when no heating or cooling equipment is added; (B) applies when it is, and takes that equipment at 100%. Under the optional methods a range enters at nameplate and then takes the 40% factor, where the standard method would cap it at 8,000 VA. Where two loads cannot run together, 220.60 lets the smaller be omitted: a heat pump that both heats and cools counts once, and a controller that prevents the compressor and the resistance element from running together removes the smaller of the two.

The reference stack gives 126 to 179 A across the four readings of the two open questions (Table 4). The charger question is worth 29 A and the interlock 25 A here, each wider than the step between two standard ratings.

220.82 and the standard method size a service for the whole dwelling

Informs D1

heat pump with supplementary heat: compressor at 100% plus supplementary heat at 65%; with an interlock the compressor is not added · cooling at 100%

the first 10 kVA counts in full and the rest at 40%, plus the largest of the heating and cooling choices 220.82(C) lists.

220.82 applies to a dwelling whose whole load is served by one 120/240 V three-wire service or feeder of 100 A or more, and is the method building departments most commonly reference (SVCE) for sizing a service. Its heat pump option takes supplementary heat at 65%, which offsets part of its larger first step: the reference stack gives 147 A with the charger in the 40% tier and 176 A with it at 100%. The standard method of Part III gives each appliance group its own factor and takes the charger and space conditioning at 100%; it is the largest result, 207 A, or 182 A with an interlock.

The EV charger's demand factor is unsettled in the adopted text

Informs D1 D5

220.57 sets a charger's load at 7,200 VA or its nameplate, whichever is larger. The optional methods list the loads that take the 40% factor (general lighting, small-appliance and laundry circuits, and appliances fastened in place, permanently connected or on a specific circuit) without naming chargers. One reading counts a hardwired charger as such an appliance; the other holds it at 100% because it runs for hours at full current, the same argument that keeps space conditioning out of the 40% tier, and points to 220.53, which in this cycle excludes chargers from the appliance demand factor. The 2026 NEC, which renumbers Article 220 as Article 120, takes the charger at 100% of nameplate in the dwelling optional method (120.82(D)); the 2025 California Electrical Code is the 2023 text, and the later edition informs a reading rather than binding one.

A volt-ampere in the 100% tier counts 2.5 times one in the 40% tier

Informs D5

Each kilowatt removed from the 40% tier lowers the 220.83(B) result by 1.7 A; each kilowatt removed from the 100% tier lowers it by 4.2 A. The ratio is the demand factor itself: a 4.5 kW water heater element is worth 8 A, 6 kW of supplementary heat 25 A. Figure 3 varies one input at a time from Case A. The four longest bars belong to the charger reading, the supplementary heat and its interlock, and the heat pump size, and none is decided by electrical work: one is a building department reading, the others are equipment choices in HVAC · Backup heat. Floor area, the input most often measured with care, moves the result by about 1.5 A per 300 sf.

3 · Measured demand: what the meter can and cannot prove

Bottom line. 220.87 lets recorded demand replace the modeled existing load, but new load enters at full calculated value; when a gas house converts, nearly everything is new and the method can exceed the 220.83(B) result.

Measured demand replaces only the existing load

ServicePanelCircuits

Informs D1

P_max highest 15-minute demand over 12 months, W · I_new new load calculated under Article 220, A · V 240 V

a quarter is added to the highest recorded demand, and the new loads are added on top at their calculated value.

The demand record is 12 months of maximum-demand data, usually the utility's interval data. Where a year is not available, a 30-day recording of 15-minute maximum demand is accepted if it is taken while the house is occupied and includes, by measurement or calculation, the larger of the heating or cooling load; the renewable-energy and peak-shaving exclusion applies only to that 30-day route.

For a gas-heated house with no central air conditioning, gas water heating, cooking and drying, and a recorded peak of 5.5 kW (typical), the existing load is 1.25 × 5.5 kW = 6,875 VA, 29 A. Every load in the conversion is new: the range at 8,000 VA (Table 220.55), the heat pump and supplementary heat, the water heater, the dryer, the charger and the ventilation equipment come to 42,320 VA, 176 A, for 205 A in total, or 180 A with an interlock (Figure 4).

Both results exceed the 220.83(B) readings with the same assumptions, because 220.83 applies the 40% factor to the range, water heater, dryer and possibly the charger, while 220.87 adds them in full. The method suits a small addition to an established electric load, the case it was written for. It helps a conversion when the recorded peak already includes loads that stay, such as an existing electric dryer or water heater, because the meter then captures their real coincidence.

4 · Load management: a setpoint in place of capacity

Bottom line. A listed energy management system may hold a service to a setpoint and the setpoint becomes the calculated load, but the setpoint counts as continuous and cannot sit below the load the system has no authority over.

An energy management system's setpoint can stand in for the calculated load

Informs D2

I_floor calculated load of everything the system cannot shed · I_service service rating

the setpoint must cover what cannot be shed, and, because it counts as a continuous load, may be no more than 80% of the service rating.

220.70 lets the maximum current setpoint of an energy management system (EMS) that complies with 750.30 be used as a single value in the service or feeder calculation, and treats that value as a continuous load. A continuous load is carried at 125%, so a 100 A service supports a setpoint of 80 A, a 125 A service 100 A and a 150 A service 120 A. 750.30 requires the setpoint to be marked and protected from change by the occupant, and the controlled loads to be dropped if the system fails. An EMS can be a smart panel, a branch-circuit controller or a limiter built into a charger. It limits load and answers the Article 220 question; a power control system (705.13) limits sources and answers the busbar question in Part 5, and one product may be listed for both.

Chargers have two forms of the same idea. 625.42(A) sets a charger's load at the maximum an EMS permits, and 625.42(B) rates a charger with a restricted-access current adjustment at its adjusted setting: a 48 A charger set to 32 A counts as 7,680 VA. Devices that let two loads share one circuit, only one running at a time, rest on the noncoincident-load rule of 220.60.

A setpoint cannot sit below the load the system cannot shed

Informs D2 D5

The plausibly sheddable loads in the reference stack are the charger, the supplementary heat, the dryer and the water heater element: interrupting each delays an outcome rather than removing it. The range, the heat pump compressor, lighting and receptacles and the small appliances are not sheddable in any useful sense; a system that switches off a cooktop mid-meal or the heat pump at the design temperature is a fault. The "uncontrolled floor" is a term of this guide, not of the code: 220.83(B) recomputed with every sheddable load removed.

For the reference stack the floor is 90 A (Figure 5). It exceeds the 80 A setpoint a 100 A service allows, so load management alone cannot keep the reference house on 100 A; on a 125 A service a 100 A setpoint covers it. With a smaller heat pump drawing 16 A, as an example of what envelope work allows (HVAC · Capacity and sizing), the floor falls to 82 A; adding a 9.6 kW range takes it to 79 A, against 80 A, a margin within the uncertainty of the nameplates. In a managed house the binding constraint moves from the service conductors to the nameplates of the loads that cannot be shed.

Capacity strategies compared

Informs D2

Table 7 sets the four ways of reconciling the load with capacity against what each leaves behind. The fitness column is for the reference stack; strategies A and B combine, and so do C and D.

Strategy A is ranked here only on amperes removed per change. Lower-nameplate appliances have their own reasons, efficiency and smaller circuits among them, which this comparison does not weigh. The cost of strategy C is dominated by the utility side and depends on two site facts, overhead or underground service and the transformer's spare capacity (Part 7). Services above 200 A, at 320 A or 400 A, commonly require a transformer change (typical).

5 · Panel ratings: bus, main, spaces

Bottom line. "A 200 A panel" is several separately chosen ratings; the busbar–main pair sets how much a solar or storage source may backfeed, and the space count and breaker type set how many circuits the panel can take.

Three ratings sit above one calculated load

Informs D3

The calculated load is a demand, not a rating; it sets the floor under the other three (Figure 6). Dwelling service conductors may have an ampacity of 83% of the service rating (310.12), the same diversity argument applied to copper: a 200 A service takes 2/0 copper or 4/0 aluminum (Table 14). The main breaker is the service rating, the number the permit and the utility use. The busbar is a rating of the panelboard, printed on its label; 408.36 requires the main not to exceed it, and a 225 A bus with a 200 A main is a standard combination.

Under the 120% rule, backfeed is limited to 1.2 × bus − main

ServicePanelCircuits

Informs D3

I_source continuous output current of the source, A · I_backfeed breaker feeding the source into the bus, A

the main and the source breaker together may load the bus to 120% of its rating, because they sit at opposite ends.

705.12(B)(2) allows the sum to reach 120% of the bus rating only when the source breaker sits at the end of the bus opposite the main, and requires a label saying not to relocate it. With the two supplies at opposite ends, load taken from the bus between them draws from both, so no section carries both full currents. A storage inverter of the 13.5 kWh class delivers 11.5 kW, 48 A continuous, and needs a 60 A breaker (48 × 1.25).

Table 8 and Figure 7 show that the allowance does not grow with panel size unless the main stays below the bus: 200 A on 200 A admits 40 A, 225 A on 225 A only 45 A, while 225 A on 200 A admits 70 A. The same rule applies to every busbar between the source and the service, subpanels included. Two other routes avoid it: a supply-side connection ahead of the service disconnect (705.11), and a listed power control system that limits combined current (705.13); both are treated in Solar & Battery · Interconnection.

Spaces and breaker type set how many circuits a panel can take

ServicePanelCircuits

Informs D3

An all-electric house adds four to six two-pole circuits to a gas house, up to twelve spaces, before lighting or automation adds anything (Table 9, typical counts). Most 120 V branch breakers in a new panel are electronic: arc-fault protection covers most dwelling circuits (210.12) and ground-fault protection covers kitchens, laundry, bathrooms, garages and outdoor outlets, including 240 V receptacles in those areas (210.8(A)). 210.8(D) adds outlets supplying ranges, wall ovens, cooking units, clothes dryers and microwave ovens, hardwired ones included, so the range and dryer take two-pole GFCI breakers; 210.8(F) covers outdoor outlets, the heat pump's among them. Combination devices need a neutral connection; a plug-on-neutral panelboard provides it at each position, where an older panel needs a pigtail to the neutral bar for each one. The switching architecture in Lighting · Switching architecture can add a relay panel with its own feeder.

6 · Arrangement: where the service, panels and feeders go

Bottom line. The arrangement of meter, disconnect and panels decides which interconnection routes stay open and where the outdoor emergency disconnect sits; location is bounded by working space, and feeders inside a house are limited by the framing rather than by voltage drop.

Three service arrangements and what each leaves open

ServicePanelCircuits

Informs D4

Replacing service equipment on a one- or two-family dwelling engages 230.85: all service conductors terminate in a disconnect in a readily accessible outdoor location, rated for the available fault current and marked as the emergency disconnect. That pushes a replacement toward an outdoor meter-main whether or not the branch panel stays indoors. Figure 8 and Table 10 compare the three common arrangements.

Location and working space are continuing obligations

ServicePanelCircuits

Informs D4

The service disconnect sits outside or inside nearest the point where the service conductors enter (230.70(A)(1)); "nearest" is a building department judgment, typically a few feet of conductor inside the wall. In front of a dwelling panel 110.26(A) requires a clear space 36 in deep, 30 in wide and 6½ ft high, and 110.26(E) reserves the panel's own footprint from the floor to 6 ft above it or the structural ceiling, whichever is lower, for electrical equipment (Figure 9). Overcurrent devices may not be in bathrooms, clothes closets or over stair steps (240.24). A garage panel is common and permitted; the clear space applies after inspection as well, and a garage that also holds a storage unit, a charger and a car has several such spaces competing for one wall.

Voltage drop rarely limits a house feeder; routing does

ServicePanelCircuits

Informs D4

K 12.9 Ω·cmil/ft copper, 21.2 aluminum · I current, A · L one-way length, ft · CM conductor area, circular mils · V 240 V

drop grows with current and length and falls with conductor area; aluminum drops about 64% more than copper of the same size.

A second-floor subpanel serving bedrooms, baths and laundry replaces many home runs through the floor with one feeder. The informational notes to 210.19 and 215.2 suggest 3% on a feeder and 5% overall; they are not requirements. A 60 A feeder on 6 AWG copper stays under 3% to about 120 ft, and the other sizes for which ampacity already governs behave alike (Figure 10). What limits the feeder is the path: no truss member may be cut (Framing · Truss members), and joist, stud and plate penetrations have limits (Framing · Notching and boring) shared with piping and ducts.

A new service re-establishes grounding and bonding

ServicePanelCircuits

Informs D4

The grounding electrode system is re-established at a replacement service (250.50): every electrode present at the building is bonded together. A metal underground water pipe in contact with earth for 10 ft or more is an electrode (250.52(A)(1)) and needs a supplemental electrode (250.53(D)(2)); a single rod needs a second rod unless it measures 25 Ω or less (250.53(A)(2)); a concrete-encased electrode in an existing footing need not be exposed to reach it (250.50, exception). Interior metal water piping is bonded (250.104(A)), and an intersystem bonding termination with at least three terminals is provided at the service for communications systems (250.94; Low-Voltage · Entrance and bonding).

7 · Code, permits and the utility

Which code applies

The 2025 California Electrical Code (Title 24 Part 3) adopts the 2023 NEC with California amendments and applies to permits filed from 1 January 2026. AB 130 (2025) holds residential building standards at this cycle until 1 June 2031, with narrow exceptions, so outside those exceptions neither a later NEC nor a new local amendment changes the text a residential permit is checked against before then. Article 705 was renumbered between cycles: the 120% rule was 705.12(B)(3)(2) in the 2020 NEC and is 705.12(B)(2) in 2023, and plan sets still print the older number.

Provisions that replacing service equipment engages

Figure 11 sorts the work into five independent questions; Table 12 lists the provisions with the reason for each.

The permit and the utility run as separate processes

Informs D2

The building permit for a service change carries the load calculation, a one-line diagram and the panel schedule, with rough and final inspections. The utility process runs separately: a service request, the utility's review of the meter location, the drop or underground lateral and the serving transformer, and its own cutover. The utility also supplies the available fault current that the emergency disconnect's rating must meet. Under the utilities' line-extension rules (PG&E and SCE Rules 15 and 16) an allowance offsets part of the utility-side work and the customer pays the rest; panel replacement is the customer's.

The utility side varies more than the customer side, and on two facts not visible from inside the house: whether the service is overhead or underground, which decides whether a larger service means trenching, and whether the transformer has spare capacity, which decides whether it is replaced. The two processes keep separate clocks, and the utility's is usually the longer.

Where it goes wrong

1. The main breaker rating read as the busbar rating. Designs that pass the load calculation fail plan check on interconnection here (Part 5).
2. The load calculation and the busbar rule treated as one finding. A service can be ample and still refuse a backfeed, or short with ample bus headroom; they are fixed by different means (Part 5).
3. An EMS proposed without the floor computed. A setpoint below the unsheddable load cannot be honored, and the setpoint is limited to 80% of the rating (Part 4).
4. A service sized before the heat pump and its backup are chosen. The interlock alone is worth about 25 A in the reference case (Part 2; HVAC · Backup heat).
5. The charger reading assumed. The calculation is submitted on the 40% reading and returned at 100%, after the equipment is chosen (Part 2).
6. Measured demand used for a full conversion, or a 30-day recording taken in a mild month or on a house with PV (Part 3).
7. The emergency disconnect missed on a replacement. Where the interior panel is the service equipment and no outdoor disconnect exists, a like-for-like swap fails inspection without one rated for the fault current (Part 6).
8. Working space lost after inspection to storage, a charger, shelving or a parked car (Part 6).
9. A grounding electrode removed by the plumbing work (Part 6).
10. Old Article 705 citations on the plan set, which invite a closer reading of the rest (Part 7).

Reference

Glossary

Busbar rating

Current rating of the panelboard's bus, on its label; independent of the main breaker.

Calculated load

The Article 220 result, or an EMS setpoint, that the service must carry.

Coincidence factor

Peak of the sum of loads divided by the sum of their individual peaks.

Demand factor

Code multiplier applied to connected load, an approximation of the coincidence factor.

EMS

Energy management system (Article 750): a listed control that limits current by shedding loads.

EVSE

Electric vehicle supply equipment, the charger.

Interlock

A control that prevents a heat pump compressor and its resistance element from running together, making them noncoincident under 220.60.

MCA, MOCP

Minimum circuit ampacity and maximum overcurrent protection on a motor-driven appliance's nameplate.

MLO

Main-lug-only panel: a panel with no main breaker on its bus.

PCS

Power control system (705.13): a listed control that limits the combined current of sources.

Plug-on neutral

Panel construction that presents the neutral at each breaker position.

SCCR

Short-circuit current rating of equipment; at the emergency disconnect it must meet the available fault current.

Supply-side connection

A source connected ahead of the service disconnect (705.11).

Uncontrolled floor

Term of this guide: the calculated load with every sheddable load removed; the lowest setpoint an EMS can honor.

Formula sheet

Service rating and the load it supports

Table 13 inverts 220.83(B): for each rating, the nameplate total of 40%-tier loads that fits once space conditioning is taken at 100%. The reference stack's 40%-tier total is 36,800 VA, or 48,320 VA with the charger in the tier. Removing 6,000 VA from the 100% tier frees 15,000 VA in the 40% tier on every row.

Service conductor sizes

Figure color legend

Red: deficient, or fails the stated criterionAmber: marginal or conditionalGreen: meets the criterionGray: existing or baselineTeal: neutral quantity, reference line or annotation; never a grade

In Figure 5 amber marks loads available to an EMS only at the cost of deferral. In Figure 3 the two teal shades mark the direction of a change, not a grade.

Code points and inputs to confirm

• The building department's reading of the charger load under 220.82 and 220.83, and which method it accepts for a replacement service
• Acceptance of a 220.70 EMS setpoint on a dwelling service and the continuous-load treatment
• California amendments to Articles 210, 220, 230, 705 and 750 in the 2025 CEC
• 210.8(F) for the outdoor heat pump: the listed-HVAC exception expired 1 September 2026 in the 2023 text; TIA 1924 proposes 2028
• Whether 220.60's noncoincident-load omission applies inside 220.82 and 220.83
• Whether hourly utility data is accepted for 220.87
• Table 310.12 or the 83% rule as adopted; terminal temperature ratings of the equipment
• Available fault current and service configuration from the utility

Sources

• NFPA 70, National Electrical Code (2023): 220.41, 220.45, 220.50–220.60, 220.57, 220.70, 220.82, 220.83, 220.87, 230.67, 230.70, 230.71, 230.85, 250.50–250.104, 250.94, 310.12, 408.36, 625.42, 705.10–705.13, 750.30. Section text checked through the secondary sources below.
• Larimer County, 2023 NEC Significant Code Changes — 230.85 text including "where service equipment is replaced, all of the requirements of this section shall apply"; 220.57.
• Mike Holt Enterprises, 2023 Code Changes: 220.70 — EMS setpoint as a single value, considered a continuous load.
• Lawrence Berkeley National Laboratory for DOE, Codes and the NEC webinar summary (April 2024) — 2023 changes to 220.87, 220.70, 750.30, 625.42 and 220.57; proposals for later editions.
• Electrical Contractor, Using optional calculations for determining existing loads (2023 NEC) — 220.87 conditions, 30-day recording, renewable and peak-shaving exclusion.
• ExpertCE, 2023 NEC: EVSE load calculations and adjustable settings — 625.42(A) and (B) text.
• Electrical Contractor, Branch-circuit, feeder and service calculations, parts L and LII — structure of 220.82(C) and 220.83(A)/(B) (2010; structure unchanged in 2023, verified against the LBL summary).
• GreenLancer, The 120% rule for solar — 705.12(B)(2) numbering in 2023, (B)(3)(2) in 2020; sum-of-breakers and center-fed methods.
• Eaton, NEC 2023: GFCI for outdoor outlets, 210.8(F) — scope and the listed-HVAC exception; EC&M, TIA proposed to extend expiration date of 210.8(F) Exception No. 2 (August 2026) — expiry 1 September 2026, TIA 1924 to 2028.
• Mike Holt Enterprises, 2023 Code Changes: 210.8; IAEI, Plugged into electrical appliance safety — 210.8(D) appliances including ranges and dryers.
• LightNOW, Top lighting and EV charger changes in the 2026 NEC — 120.82(D), charger at 100% of nameplate.
• Silicon Valley Clean Energy, Service Optimization Guide for Building Officials (2024) — Article 220 methods in retrofit practice, 220.82 as the method most commonly referenced; a cited study of 22,000+ California homes, 86% peaking below 50 A.
• Canary Media, Yes, it's possible to electrify a home on just 100 amps — Peninsula Clean Energy finding on all-electric homes.
• Sacramento Valley Association of Building Officials summary, 2025 California Electrical Code (via City of Grass Valley) — edition and amendment overview.
• Brownstein Hyatt Farber Schreck, AB 130 places new limitations on building code updates for residential buildings — freeze to 1 June 2031.
• Chiltrix CX35 and CX65 specifications — air-to-water heat pumps at 16 A and 37 A MCA; Tesla Powerwall 3 datasheet — 11.5 kW, 48 A continuous. Used only to bound reference values.
• Companion guides: HVAC, DHW & Ventilation, Framing, Solar & Battery, Plumbing, Lighting (set v2); Low-Voltage (set v2).

Set v2 draft 1b, 2026-10-23: Low-Voltage references link to the set v2 guide (Entrance and bonding). Draft 1, 2026-10-23: rewritten as a generic theory guide to spec set v2 from the v1 guide (archived). Load stack aligned with the HVAC guide's 3-ton reference and Title 24 backup cap; 220.82, the standard method and 220.70 added; EMS setpoint limited to 80% of the rating as a continuous load; 220.87 recomputed for a full gas conversion and its PV conditions added; working-space, voltage-drop and code-flow figures added; house values moved to the House Project Guide. After review: feeder connection in the meter-main arrangement corrected to 705.12(A); 210.8(D) appliance GFCI and the 210.8(F) HVAC exception expiry added; 220.53 threshold, the 2026 NEC charger rule, the EMS–PCS distinction and conditional nameplate-reduction results added; headings tightened. Values from one script. Draft 1a, 2026-10-23: Solar & Battery, Plumbing and Lighting links repointed from the v1 files to the v2 guide anchors.

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