{
"phase": "phase2",
"nec_cycle": "2023",
"checks": [
{
"section": "690.7",
"topic": "Max system voltage (cold Voc)",
"status": "PASS",
"evidence": "Longest string 8S cold Voc 491.5 V <= 550 V MPPT-fault / 600 V abs (margin 58.5 V to fault, 108.5 V to abs). Tmin -40C; analytic+pvlib+vocmax+independent agent agree. 9S=553V REJECTED (>550)."
},
{
"section": "690.8(A)",
"topic": "Max circuit current",
"status": "PASS",
"evidence": "Per string Isc x1.25 = 17.3 A (each string a dedicated homerun). MPPT1 internally combines 2 strings = 27.7 A actual <= 31 A MPPT1 Isc rating; MPPT2/3 single string <= 19 A."
},
{
"section": "690.8(B)",
"topic": "Conductor ampacity after 310.15 derates",
"status": "PASS",
"evidence": "PV 8Cu derated 19.1A >= 17.3A (8 CCC, 0.70 fill); AC 4Cu; per-pack 2/0Cu; bank 400kcmil (or 2x2/0 / 2x4/0)."
},
{
"section": "690.9 / 690.9(A) Ex",
"topic": "PV source-circuit overcurrent (fusing)",
"status": "PASS",
"evidence": "NOT required: MPPT1 parallels only 2 strings -> max backfeed 1.25xIsc=17.3A <= module 30A series fuse (3+ parallel strings would require fuses). MPPT2/3 single string. No combiner."
},
{
"section": "690.9 / 240 / 480.9",
"topic": "Battery overcurrent (per-pack Class-T)",
"status": "PASS",
"evidence": "2x 175A Class-T (DC, 20kAIC), one per pack, >= 125% x 124.7A/pack; <= 2/0 cable 175A. Bank aggregate 350A coordinated with the bank conductor."
},
{
"section": "690.9 / 710.15",
"topic": "Inverter AC output overcurrent",
"status": "PASS",
"evidence": "70A 2-pole >= 125% x 50A; protects 4Cu (240.4(D)); EGC 8AWG."
},
{
"section": "690.11",
"topic": "DC arc-fault (AFCI)",
"status": "PASS",
"evidence": "EG4 18kPV integrated PV AFCI (690.11 / UL1699B, per datasheet)."
},
{
"section": "690.12",
"topic": "Rapid shutdown",
"status": "VERIFY-AHJ",
"evidence": "18kPV has an integrated RSD initiator (datasheet cites NEC 2020:690.12). Detached ground-mount (not on a building) is likely exempt, but PV/DC conductors enter the dwelling -> confirm the VT DPS inspector's stance for NEC 2023. Initiator present if required."
},
{
"section": "690.13 / 690.15",
"topic": "PV + equipment disconnects",
"status": "PASS",
"evidence": "18kPV integrated PV disconnect; add an external load-break DC/PV disconnect for service. Battery: 2 per-pack disconnects + a 249A-class bank disconnect within sight of the inverter."
},
{
"section": "690.41(B)",
"topic": "System grounding / GFDI",
"status": "PASS",
"evidence": "18kPV integrated PV ground-fault monitoring (690.41(B)) + pole-sensitive leakage-current monitor + integrated SPD (per datasheet)."
},
{
"section": "690.43 / 690.45",
"topic": "Equipment grounding & EGC size (250.122)",
"status": "PASS",
"evidence": "EGCs: PV 10AWG (no source OCPD), per-pack 6AWG (175A), AC 8AWG (70A), bank 4AWG (sized to disconnect). Bond all array frames + enclosures + the battery busbar."
},
{
"section": "690.47",
"topic": "Grounding electrode (array + DC)",
"status": "ACTION",
"evidence": "Ground-mount: drive an array grounding electrode (rod), 6AWG Cu GEC bonded to the dwelling GES (690.47(A)). Carries forward from Phase 1; verify for the expanded array footprint."
},
{
"section": "690.31",
"topic": "Wiring methods",
"status": "PASS",
"evidence": "PV in Sched-40 PVC conduit (squirrel/UV, Swarm \u00a716); 8Cu THWN-2/PV 90C. 4 strings -> split across 2 conduits to relax the 8-CCC fill."
},
{
"section": "705",
"topic": "Interconnection (utility)",
"status": "N/A",
"evidence": "Off-grid, no utility interconnection (no 705.12 backfeed limit). Generator AC-IN to the 18kPV (200A AC bypass / 90A gen) with the main panel subfed and its main breaker locked off (Swarm \u00a717); transfer is internal to the hybrid inverter."
},
{
"section": "706.7 / 706.20",
"topic": "ESS \u2014 multi-pack arrangement & control",
"status": "PASS",
"evidence": "2x Docan S3 (LFP, JK-PB2A16S20P BMS) in parallel on a DC busbar. Each pack has its own BMS + Class-T + disconnect. Bank discharge 249A split 124.7A/pack \u2014 within the 150A/300s JK OCP (17% headroom) and the 157A EVE-cell limit. C-rate 0.397C."
},
{
"section": "706.30 / 480.7",
"topic": "ESS disconnecting means",
"status": "PASS",
"evidence": "Per-pack disconnects + a bank disconnect (lockable, within sight of the ESS); the 18kPV battery port is the inverter-side disconnect. BMS opens on cell-level faults."
},
{
"section": "706.31 / 480.9",
"topic": "ESS overcurrent protection",
"status": "PASS",
"evidence": "Per-pack 175A Class-T (20kAIC > pack prospective fault). Layered: JK-BMS (150A/300s OCP, 300A SC) protects cells; Class-T protects each pack cable."
},
{
"section": "706.x / BMS comms",
"topic": "Multi-pack BMS communications",
"status": "VERIFY",
"evidence": "2 packs: JK-BMS master/slave, one master -> 18kPV via CAN (a SINGLE comms link, vs 2 for a parallel-6000XP path). 18kPV native closed-loop is EG4-48V; the Docan/JK pack runs via a CAN profile -> confirm on arrival. Open-loop fallback fully viable (no battery-life penalty)."
},
{
"section": "710.15",
"topic": "Stand-alone system output",
"status": "PASS",
"evidence": "18kPV 12kW 120/240V split-phase, output 50A; off-grid, no utility backfeed. Continuous line 8000W/120V leg covers the household peak; surge 13.5kW (w/o PV)."
},
{
"section": "690.53/54/56 / 110.21",
"topic": "Labels & placards",
"status": "ACTION",
"evidence": "Max system voltage 491.5V (690.53), inverter output 12kW/50A (690.54), RSD placard if AHJ requires (690.56(C)), DC disconnect + directory, per-pack battery hazard labels. Generate from these computed ratings."
},
{
"section": "NFPA 855 / VT 2025 Fire Code",
"topic": "ESS fire code (OUT OF SCOPE \u2014 GATE)",
"status": "FLAG",
"evidence": "2 packs = 32.2kWh nameplate. Swarm \u00a74: even 2 packs (32kWh) likely crosses the 20kWh residential threshold (3 packs/48kWh definitively) -> detached non-combustible shed >=10ft, UL9540 listing or AHJ hazard-mitigation analysis, + propane-heater combustion-air/ventilation/separation. NOT engineered here \u2014 pre-clear with VT DPS in writing before ordering the 2nd pack."
},
{
"section": "Voltage drop (design target)",
"topic": "DC<=2% / batt<=1% / AC<=2%",
"status": "PASS",
"evidence": "DC 1.329% (150-250ft: {'150': 0.997, '200': 1.329, '250': 1.661}); per-pack 0.235%; bank 0.313%; AC 0.128%. (Informational; not NEC-mandated.)"
}
],
"summary": {
"PASS": 16,
"VERIFY-AHJ": 1,
"ACTION": 2,
"N/A": 1,
"VERIFY": 1,
"FLAG": 1
}
}