Enphase IQ System Controller 3
The IQ System Controller 3 is the automatic transfer switch and grid-form controller for an Enphase backup install. It's what turns a basic grid-tied PV system into one that keeps the lights on when the utility goes down.
- Type
- Automatic transfer switch + grid-form controller
- Function
- Islands home during grid outage, signals microinverters and batteries to grid-form
- Warranty
- 5-year Enphase
- Enclosure
- NEMA 3R (outdoor)
- Transition
- Milliseconds (UPS-style no-break)
- Configuration
- Between main service panel and backup loads panel
About this item
The IQ System Controller 3 is the automatic transfer switch and grid-form controller for an Enphase backup install. It's what turns a basic grid-tied PV system into one that keeps the lights on when the utility goes down.
The Controller monitors the grid 24/7. When the grid drops, it islands the home in milliseconds and signals the IQ8 microinverters and IQ Battery 5P units to grid-form. The microinverters now follow the battery instead of the grid, the batteries push real power into the panel, and the install keeps the protected loads up without an outage interruption. When the grid comes back, the Controller re-synchronizes and folds the system back into the grid.
Sits between the main service panel and a backup loads panel. Sized for whole-home or critical-loads backup depending on how the loads are wired. Pairs with the IQ Combiner 5C and IQ Battery 5P for a complete Enphase backup stack. NEMA 3R outdoor mount, 5-year Enphase warranty.
More Accessories
2023 NEC Sticker Pack
This sticker pack covers the labels and placards a solar install needs to pass inspection under the 2023 NEC. It includes the rapid shutdown placards, disconnect and inverter markings, conduit labels, and the power source directory, all printed on durable weather-rated stock that meets the code’s permanence rules. One pack handles the common warning and identification points on a typical residential system.
$20
BOSS Box
The EG4 BOSSBox is a freestanding outdoor cabinet that houses your EG4 batteries and hybrid inverters in one weatherproof package, so you skip the wall mounting and the extra labor. The NEMA 3R steel enclosure holds up to three WallMount batteries and two hybrid inverters, and it cools through passive vents with no fans to fail. A clean way to set up whole-home backup or off-grid storage.
$2,952
Emporia Vue 3 Home Energy Monitor 16 Sensors
The Emporia Vue 3 wires into your electrical panel and shows where your power is actually going, from the whole-home total down to 16 individual circuits. It reads within about 2% of the utility meter and updates in near real time in the app, and it tracks solar production and net metering too. A simple way to see usage, spot waste, and watch a solar system without an expensive sub-meter.
$199