The 46 design checks every solar plan set should pass.

Every overcurrent device rating must be in the NEC 240.6(A) standard size table.

Shows up as: Breaker or fuse rating is not a size you can buy

Breakers and fuses only come in specific standard sizes (like shoe sizes). This one is set to a size that isn't actually made, so it needs to round to the nearest real size you can buy.

Verify overcurrent protective device rating matches the conductor ampacity it protects.

Shows up as: Breaker is too large for the conductor it protects

A breaker is the safety valve for a wire: it has to trip before the wire overheats. Here the breaker is too big for the wire it's protecting, which means the wire could get dangerously hot before the breaker ever shuts off.

Every conductor needs an OCPD at the source unless it qualifies for a tap-rule exception.

Shows up as: Conductor has no overcurrent device at its source

Every wire needs a breaker or fuse at the point where its power comes from. This wire doesn't have one, so there's nothing to shut it off if it shorts out.

Verify upstream OCPDs are sized at or above downstream OCPDs (selective coordination).

Breakers should get smaller as you move away from the power source, like branches off a tree trunk. Here a breaker downstream is bigger than the one feeding it, which can let the wrong breaker trip first during a fault.

Branch + feeder voltage drop within recommended limits (≤3% branch, ≤5% total).

Shows up as: Wire run loses too much voltage over its length

Electricity loses a little 'push' over long wire runs, like water pressure dropping over a long hose. This run loses too much, which can make equipment underperform: usually fixed by using a thicker wire.

Grid-tied inverter output conductors: voltage rise ≤2% target / ≤5% over-voltage-trip ceiling (IEEE 1547 + ANSI C84.1 trip window).

A solar inverter PUSHES power out to the grid, so its wire to the grid gains a little voltage instead of losing it (the opposite of a normal appliance). If it gains too much, the inverter sees the voltage as too high and shuts itself off on the sunniest part of the day: losing production. The fix is a thicker wire or a shorter run.

Equipment Grounding Conductor sized per NEC 250.122 table based on upstream OCPD rating.

Shows up as: Equipment grounding conductor is undersized

The ground wire is the safety path that carries fault current away so a metal enclosure never becomes live. This ground wire is too small for the breaker protecting it and needs to be sized up.

Load-side wires must include EGC; supply-side wires to a bonded source must not.

Ground wires belong on some runs and not others depending on which side of the main service they're on. This run has the ground wire handled the wrong way for its location.

Grounding Electrode Conductor sized per NEC 250.66 based on service-entrance ungrounded conductor size.

The main grounding wire that ties your whole system to the earth (via a ground rod or water pipe) is sized off the service conductors. This one doesn't match and needs adjusting.

A GES must be connected to the service-entrance equipment.

The system has to be physically tied to the earth through a grounding electrode (a ground rod, the water pipe, or rebar in the foundation). No grounding electrode is connected to the service yet.

GEC must land at the service disconnect (not a downstream block).

The main grounding connection has to land at the service disconnect, the first shutoff after the meter, not somewhere deeper in the system. It's currently attached to the wrong spot.

The first OCPD-providing block downstream of the meter MUST carry both the N-G bond and the GES. Downstream blocks must NOT.

Exactly one piece of equipment, the first shutoff after the meter, is where the neutral and ground get bonded together and the earth connection lands. That bonding is either missing here or happening at the wrong box.

Maximum DC voltage on a PV string within the inverter's maximum DC input voltage (NEC 690.7).

Solar panels wired in a row add up their voltage, and on a cold sunny day that voltage spikes. This string's voltage can climb past what the inverter can safely handle: usually fixed by putting fewer panels in the string.

Panel count per string must keep Voc (cold) ≤ inverter max and Vmp (hot) ≥ inverter MPPT minimum.

A solar string needs enough panels to start the inverter on a hot day, but not so many that it over-volts on a cold day. This string is outside that safe window and the panel count needs adjusting.

Per-MPPT current does not exceed the inverter's rated MPPT input current.

Each input on the inverter can only take so much current. This input is being fed more than it's rated for, which means some of the solar production would be clipped or the input stressed.

Panel count per AC branch must satisfy NEC 705.13 / 690.8 continuous-current limit AND the microinverter manufacturer's max_units_per_branch[breakerSize] spec table.

Microinverters chain together on a shared circuit, and there's a limit to how many fit on one branch before the wire is overloaded. This branch has too many panels on it and needs to be split.

Every solar string is assigned to a valid MPPT on its inverter (not orphaned or over-stuffed).

Each solar string has to be assigned to an actual input on the inverter. One of these strings isn't assigned to a valid input, so it's effectively floating.

Supply-side interconnections meet NEC 705.11 conductor sizing + service disconnect requirements.

When solar taps in ahead of the main breaker, special conductor and disconnect rules apply. This supply-side connection doesn't meet one of those requirements yet.

Equipment connected on the supply side of the service (supply-side tap / direct meter connection) must be listed suitable for use as service equipment (SUSE).

Equipment wired in ahead of the main breaker (like a supply-side tap disconnect, or a panel fed straight from the meter) has to be built and labeled for that job: 'suitable for use as service equipment.' This one isn't marked as such yet: confirm the label on the real equipment and flip the Service Rated toggle, or connect it after the main breaker instead.

Unprotected tap conductors on a supply-side interconnection respect NEC §705.11(C). Threshold depends on project scale: residential = 10 ft inside building, commercial = 16.5 ft (or 71 ft with cable limiters). Wires already sized to their downstream OCPD are skipped: they satisfy 705.11(C)(1)(b). The ceiling is an INSIDE-building limit: a conductor whose tap location is declared Outside (or Considered outside per §230.6) is exempt, and the §230.6 case gets an info note since that section is written for service conductors.

When you tap solar in ahead of the main breaker, the unprotected stretch of wire before its disconnect has a strict length limit INSIDE the building. This run is too long for where it's installed: move the disconnect closer to the tap, or, if the wire actually runs outdoors, mark its tap location as outside in the conductor schedule and the limit no longer applies.

Connected blocks share compatible voltage + phase (no single-phase wired to three-phase, no 240V to 480V).

Two pieces of connected equipment expect different voltages or phases (like plugging a 120V device into a 240V outlet). They can't be wired together as-is.

Breaker pole count matches the phase configuration (1P for 120V, 2P for 240V split, 3P for 208/480V wye/delta).

A breaker needs the right number of 'poles' for the voltage it's switching: single-pole for 120V, two-pole for 240V, three-pole for three-phase. This breaker's pole count doesn't match its circuit.

120% rule, sum rule, feed-through tap, and derate enforcement for load-side solar interconnections.

There's a limit to how much solar and battery power you can backfeed into a panel before its busbar is overloaded (the '120% rule'). This design exceeds that limit: options are a bigger panel, a smaller main breaker, or a Power Control System.

PCS-controlled installations: combined source current must not exceed declared PCS limit, and a 705.13-listed host device must be present.

A Power Control System is a smart device that actively limits how much combined power hits the busbar. Either the limit is set too high for the panel, or the listed device that's supposed to enforce it is missing from the design.

Conductors between the PCS host and the protected panel must be sized for PCS setpoint × 1.25 (continuous-load factor), and the OCPD must not exceed the PCS setpoint.

The wires between the Power Control System and the panel it protects have to be sized for the limit the PCS enforces. The wire size or its breaker doesn't line up with that limit here.

A MLO (main-lugs-only) backup panel downstream of a PCS host needs at least one of: (1) external inline OCPD ≤ panel rating, (2) PCS Panel Limits configured for the backup busbar, (3) total island-mode source capacity ≤ panel rating. The gateway internal main breaker does NOT protect the backup panel.

A backup loads panel with no main breaker of its own needs something else to protect it during an outage. Right now nothing is guaranteeing the backup panel's busbar can't be overloaded: the gateway's internal breaker doesn't count.

AC-coupled solar in the Tesla backup circuit ≤ 7.68 kW per Powerwall (10 kW per PW3 with Expansion). Excess must be routed line-side of the Gateway.

Tesla limits how much solar can sit on the backup side of the Gateway per Powerwall. This design has more solar in the backup circuit than the batteries can handle, so some of it has to move to the grid side of the Gateway.

Line-side tap interconnection requires a panel with a line_tap port (main / meter-main) or an external service-entrance tap point. MLO panels have no line_tap port.

A line-side tap needs a panel that actually has a tap point ahead of its main breaker. This panel is main-lugs-only and has no such tap point, so the connection can't land there.

Load-side feeder tap conductors must meet a NEC 240.21(B) length tier: (B)(1) ≤10 ft (ampacity ≥ terminating OCPD), (B)(2) ≤25 ft (ampacity ≥ 1/3 feeder OCPD), or the special >25 ft tiers (B)(4)/(B)(5). With a power source on the feeder, 705.12(A)(3) raises the 1/3 basis to (feeder OCPD + Σ PV OCPDs). Errors on an undersized tap; warns on a >25 ft tap. A tap whose location is declared Outside (or Considered outside per §230.6) skips the length tiers and is checked against the (B)(5) CONDITIONS instead: it must terminate in a single OCPD, rated ≤ the conductor ampacity, at the point of entry; failing either is an error, since without that termination no 240.21(B) tier permits the run. Supply-side line taps (705.11) are excluded. See docs/NEC_240_21B_FEEDER_TAPS.md.

A tap wire connects to a feeder without its own breaker at the tap, so the code limits how long it can be and how small it can be. Short taps (≤10 ft) must carry at least their end breaker; ≤25 ft taps must be at least a third of the feeder's breaker, and because solar adds a second source, that third is figured on the feeder breaker PLUS the solar breaker, so the tap wire often has to be a size or two bigger. A tap that runs OUTSIDE the building has no length limit at all, but only if it ends in one breaker or fuse, no bigger than the wire can carry, right where it enters the building, without that, the outside allowance doesn't exist. This tap doesn't meet its rule, so upsize the wire, add or resize the end breaker, or shorten/relocate the run.

A load-side tap on a feedthrough FEEDER is governed by NEC 705.12(A) (Feeders and Feeder Taps), NOT the busbar 120% rule (B)(2) or busbar feed-through (B)(5). Acceptable when (A)(2)(a) feeder ampacity ≥ primary-source OCPD + 125% PV, OR (A)(2)(b) an OCPD ≤ feeder ampacity at the load-side connection (the downstream panel main). Warns when (b) is not met, MLO downstream panel, or a downstream main exceeding the feeder ampacity (the 310.12(B) 83% main feeder, no longer auto-qualifying post-tap), pointing to (a) as the alternative. A tap does NOT increase the feeder load; this is protection coordination, not overload.

Solar tapped onto the feeder that feeds the downstream panel. The tap doesn't add load to that wire, but it does change which code rule applies: the downstream panel either needs its own main breaker no larger than the feeder can carry, or the feeder has to be big enough for its load plus the solar. Right now neither is confirmed: add a correctly-sized main on the downstream panel, or verify the feeder is large enough.

Detect ambiguous service topologies where multiple panels could be the service disconnect (single-disconnect rule).

The service can only have one main shutoff, but this layout has more than one panel that could be it. The drawing needs to make clear which single panel is the service disconnect.

Every string inverter AC output is wired AND has an OCPD (breaker / fuse / PCS-controlled port) upstream: catches floating inverters when a combiner runs out of breaker slots.

Every inverter's AC output needs both a wire and a breaker/fuse feeding into the system. This inverter is missing one: often because a combiner ran out of breaker slots and left it stranded.

Current into a node equals current out (no source receiving current, no load driving an output, combiner outputs sum branch inputs).

The current going into a junction should equal the current coming out: power can't appear or vanish. The numbers don't balance here, which usually points to a mis-wired or mis-sized connection.

AC source count must not exceed the gateway's physical smart-port slot count. Excess sources require an AC combiner upstream or a sub-distribution panel.

The gateway only has so many physical slots for power sources to plug into, and the design is trying to plug in more than it has. You'd need a combiner panel to merge some sources first, or a bigger gateway.

Multi-breaker hosts (gateway, smart panel, combiner) shouldn't draw breakers in physically-uninstalled slot positions. Auto-fix prunes unwired positional slots to match installed hardware.

The panel is showing breakers in slots where nothing is actually wired. These phantom breakers should be removed so the drawing matches what gets installed.

Wire created without a matching conduit-defaults rule: both conduitType + insulationType remain undefined. Pick values manually or extend the rules table.

Every wire run needs a conduit type (the pipe it runs through) and a wire type. The system couldn't auto-pick them for this run, so they need to be chosen manually.

Required connection points (utility input, main breaker, etc.) have wires landing on them.

A required connection point (like the utility feed or the main breaker) doesn't have a wire landing on it. Something that needs to be hooked up isn't yet.

Pass-through devices (junction boxes, disconnects) have both input AND output wired.

A pass-through device like a junction box or disconnect has a wire going in but nothing coming out (or vice versa). It needs to be wired through on both sides to actually carry power.

Panel breakers have a downstream wire connected (no orphans drawn but not wired).

A breaker is drawn in the panel but nothing is wired to it. Either wire something to it or remove it so the drawing reflects the real install.

Wires terminate at a known connection point on a block: not free-floating in space.

A wire ends in empty space instead of landing on a real connection point. Both ends of every wire need to attach to actual equipment.

Wire topology is consistent (no upstream loops, no source-into-source connections).

Something is wired in a way that doesn't make electrical sense: like a loop feeding itself, or two power sources wired directly into each other. The wiring path needs to be corrected.

Solar panels have been set for the design (not left as the template placeholder).

This design started from a template, and the solar panels shown are just the template's example: not your actual panels. Open Project Settings → Solar Equipment to pick the real panel model and count before this drawing goes anywhere official.

An AC module has an integrated microinverter: the string must not also carry a separately selected MLPE device.

An AC module already has its microinverter built into the panel, so adding a separate microinverter or optimizer to the same string is counting the same equipment twice. Pick one: the AC module on its own, or ordinary DC panels with the separate device.

Monitoring devices are compatible with the inverters/gateways they monitor.

The monitoring device (the part that reports production to an app) has to be compatible with the inverter or gateway it's watching. This pairing isn't a supported combination.

Every meter socket has a current rating set. Recipes may defer rating at creation; this check ensures it is resolved before planset signoff.

The meter socket doesn't have an amperage rating set yet. It needs one before the plan set is finalized so the service size is documented.

Wall-mounted equipment on the elevation pages: minimum mounting heights (AFF), manufacturer/NEC working clearances free of obstructions, no physically overlapping enclosures, operating handles within the 6'-7" max reach, and ESS kept 3 ft from doors/windows.

The elevation drawing shows where equipment physically hangs on the wall, and inspectors check it against real-world rules: boxes can't overlap, shutoff handles must be reachable (no higher than 6'-7"), equipment needs its required breathing room, and batteries have to keep their distance from doors and windows. Something on the wall breaks one of those rules: drag it to a compliant spot.