NEC 706 — Energy Storage Systems: Tesla Powerwall, Enphase IQ Battery, and the New 2023 Rules

NEC Article 706 covers Energy Storage Systems (ESS) — what residential customers usually call "home batteries." The category exploded in NJ residential after 2022 when solar net-metering economics shifted toward self-consumption and PSE&G's standby-rate proposals made backup storage economically attractive.

The major residential ESS products in NJ in 2026:

• Tesla Powerwall 3 — 13.5 kWh capacity, 11.5 kW continuous output, integrated solar inverter
• Enphase IQ Battery 5P / 10C — 5 kWh / 10 kWh modular, AC-coupled
• Franklin WHP — 13.6 kWh, hybrid inverter
• Generac PWRcell — 9-18 kWh modular, DC-coupled

Disconnect required (706.15): every ESS needs a disconnect that can de-energize the battery from the rest of the system. Located within sight of the ESS, accessible to first responders. Lockable in the OPEN position. Required to be marked clearly.

Working space (706.7 / 110.26): same 36-inch front clearance, 30-inch width, 6.5-ft height working space required for any panel applies to ESS units. NJ inspectors enforce this strictly because ESS units are heavier than panels and harder to remove for service.

Signage (706.16): the ESS installation must be marked with permanent signage identifying:

• The presence of an energy storage system
• The location of the disconnect
• The voltage and capacity ratings
• A warning that the system may energize even when utility power is out

Interconnection with PV (705 / 706 combined): when you have solar PLUS an ESS, the system uses an "AC-coupled" or "DC-coupled" architecture. AC-coupled (Enphase IQ Battery + IQ Microinverters) is simpler — solar AC output charges battery via separate inverter. DC-coupled (Tesla Powerwall 3, SolarEdge with battery) shares one inverter — typically more efficient.

Backed-up loads via critical-loads sub-panel: the standard residential ESS install creates a "critical loads sub-panel" or uses a smart panel like SPAN to selectively power priority circuits during an outage. The sub-panel feeds from the ESS during outages, transfers seamlessly when utility comes back. Requires a transfer mechanism (gateway, ATS) per NEC 706.

NJ utility interconnection: PSE&G and JCPL both have interconnection processes for ESS-paired solar. The application typically requires:

• AC disconnect at the inverter, lockable in OPEN, accessible to utility
• ESS disconnect at the battery
• Critical-loads sub-panel single-line diagram
• Net-metering setup (separate from ESS operations)

For ESS one-line diagrams, our SLD Builder at /tools/single-line-diagram is currently template-based for solar without ESS. Full ESS-included templates ship in Phase 3 (React Flow refactor).