Why a Dedicated Circuit?
Plug-and-play solar inverters draw 800–1,800W continuously during peak production. Sharing a circuit with refrigerators, space heaters, or other loads risks tripped breakers and reduced solar output. A dedicated 15A or 20A circuit is recommended.
Related: wiring & electrical setup, UL 1741 guide, local codes, and best AC safety devices.
Circuit Sizing
| System Size | Max AC Draw | Min Circuit | Breaker |
|---|---|---|---|
| 400W (2 panels) | ~400W | 15A | 15A |
| 800W (4 panels) | ~800W | 15A | 15A dedicated |
| 1800W (full kit) | ~1,800W | 20A | 20A dedicated |
NEC 210.21: Continuous loads (3+ hours) should not exceed 80% of circuit capacity. 800W on 15A (1,440W max continuous) is acceptable.
Outdoor Outlet Requirements
- GFCI protection: Required for all outdoor outlets (NEC 210.8)
- Weatherproof cover: In-use (bubble) cover if cord stays plugged in
- WR-rated receptacle: Weather-resistant outlet required outdoors
- Location: Within 25–50ft of panel mounting location to minimize extension cord length
- Permit: New outdoor outlets typically require electrical permit — see permits guide
Extension Cord Best Practices
If your solar outlet is not adjacent to the panel location, use a heavy-duty outdoor extension cord:
- 10AWG minimum for 800W+ systems on runs up to 50ft
- SJTW rated — weatherproof vinyl jacket for outdoor use
- 15A / 1,875W rated — match or exceed circuit breaker rating
- UL listed — avoid cheap indoor-only cords outdoors
- Route cord away from foot traffic; secure with cable clips, not nails through cord
Smart Plug Integration
Install a WiFi smart plug with energy monitoring between the outlet and solar inverter to track daily production. See smart plug monitoring guide. Use a multimeter to verify outlet voltage (120V ±10%) before first connection.
Renter-Friendly Option
If you can't install a new outlet, run the kit's AC cord through a balcony door gap to an interior outlet on a dedicated circuit. See renter guide.