Tesla Powerwall 3 + Backup Switch / Gateway 2 Single-Line Wiring Diagram
Single-Line Diagram for the Tesla Powerwall 3 showing how all 6 DC solar strings land directly inside the Powerwall 3 enclosure, eliminating external string inverters, and how the utility Meter-Collar Backup Switch cuts transfer wiring time by 75%.
Single-Line Electrical Schematic (SLD)
Service Rating: 200A Service (Backup Switch or Backup Gateway 2)
[ROOFTOP SOLAR: Up to 6 DC Strings (20kW DC Max)]
| (#10 AWG PV Wire + Tesla MCI Rapid Shutdown Devices)
v
[TESLA POWERWALL 3 (13.5kWh LFP + 11.5kW 6-MPPT Inverter)] ===(DC Expansion Harness)===> [PW3 Expansion Pack]
|
(#6 AWG Cu L1/L2/N/G + Low-Voltage 4-Pin Comms)
v
[60A 2-Pole Breaker Inside Existing 200A Main Load Center]
^
[TESLA BACKUP SWITCH (Plugged Directly Behind Utility Meter Socket)] OR [Tesla Backup Gateway 2]Conductor Gauge (AWG), Breaker & Torque Schedule (75°C Column)
| Circuit Segment | Conductor Gauge (AWG) | OCPD Breaker / Fuse | Conduit & Lug Torque |
|---|---|---|---|
| Powerwall 3 AC Output -> Main Panel / Gateway 2 | #6 AWG Copper THWN-2 (L1, L2, Neutral) + #8 AWG Cu EGC | 60A 2-Pole Breaker (Supports 48A / 11.5kW continuous output) | 1'' EMT · Torque PW3 AC terminals per internal door label |
| Solar Roof Array -> Powerwall 3 6x MPPT Inputs | #10 AWG UL 4703 PV Wire (60V–550V DC operating window) | Integrated Rotary DC Disconnect on Side of Powerwall 3 | 3/4'' or 1'' EMT · Install Tesla Mid-Circuit Interrupters (MCI) on roof for NEC 690.12 RSD |
NEC 2023 Code Compliance & Electrician Commissioning Checklist
⚖️ NEC 2023 CODE📜 Mandatory NEC Code Compliance Notes (NEC 2023 Art. 690, 705 & 706)Pass your municipal AHJ rough and final electrical inspection on the first visit.
- ⚡NEC 705.12(B) 120% Busbar Rule: When backfeeding a 60A Powerwall 3 breaker into a 200A panel without a Meter-Collar Backup Switch or upstream Gateway, verify whether a main breaker derate (e.g., 175A main breaker) or Hawaiian tie-in is required.
- ⚡Rapid Shutdown: Powerwall 3 uses passive Tesla Mid-Circuit Interrupters (MCI-2) bolted to the solar rail to drop string voltage below 30V within 30 seconds.
🛠️ COMMISSIONING✅ Master Electrician Pre-Energization & Commissioning ChecklistVerify polarity, CT orientation, and firmware before throwing the main breaker.
- ✓Verify each of the 6 MPPT inputs is under the 550V maximum cold-morning open-circuit voltage (Voc) limit.
- ✓Confirm hardwired Ethernet AND Wi-Fi/Cellular heartbeat so the 10-year Tesla warranty remains active.
❓ ELECTRICIAN FAQWhat is the Tesla Backup Switch?
It is a UL-listed smart collar that plugs directly between the utility glass electric meter and your meter socket jaw, providing whole-home 200A outage transfer without rewiring your main breaker panel.
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