Battery storage systems have gone from niche to mainstream, and electricians who know how to install them are in high demand. Tesla Powerwall, Enphase IQ Battery, Franklin WH, and Generac PWRcell are the big players in residential. Each has its own installation manual and its own utility interconnection implications. Before you install any of these, take the manufacturer training - not optional, it’s required for warranty and often for permitting.
The NEC governs these under Article 706 (Energy Storage Systems, added in 2017). Key requirements: the ESS must have a disconnect that can be operated without entering the enclosure, the battery enclosure must be ventilated, and the system must have a manual disconnect accessible to emergency responders. Location: most jurisdictions prohibit installation in living spaces or bedrooms.
Whole-home backup vs partial backup: whole-home backup requires a transfer switch and appropriately sized battery capacity. Partial backup (essential loads only) is more common - a critical loads panel fed from the battery system handles lights, refrigerator, some outlets. Size the critical loads carefully; customers always underestimate what they need.