STEP 7: Make Solar PV Connections

Note

See Powerwall 3 AC and PV Wiring for wiring specifications.

Note

As noted in Design Considerations, third party MLPE solutions, such as optimizers, are not compatible with Powerwall 3.

CAUTION

Only connect PV wires to the integrated DC isolator as described in this step. Do not attempt to modify factory-installed wiring or connect PV wires to any other terminals.

Note

If there are more than three PV strings, strings can be combined upstream of Powerwall 3 so long as the voltage and current ratings of the system do not exceed the capabilities of Powerwall 3.

Before connecting the PV strings to Powerwall 3, use a PV string tester to test each string, confirming it is performing as expected. Refer to the testing requirements of AS/NZS5033:2021 cl 6.3.2.
Before terminating any conductors inside Powerwall 3, turn the Powerwall 3 switch OFF to shut the system down, then turn the integrated DC isolator OFF. See Powerwall 3 Switch Locking Mechanisms for instructions to lock the integrated DC isolator in the OFF position.
Warning
Before proceeding, confirm both switches are OFF and there is a lack of voltage at the PV terminals.
Clear out any debris that may be present in the PV wiring terminals.
Warning
Metal debris like loose wires or metal shavings could create a high voltage risk when Powerwall is turned on.
Route the PV conductors and PV array Protective Earth into the enclosure, through the conduit or cable gland. Create a service loop with extra wiring.
Connect the PV array Protective Earth to an equipment grounding terminal in Powerwall:
1. Strip the conductor insulation up to 19 mm.
2. Insert the grounding conductor in an equipment grounding terminal and tighten the screw in the Earth terminal to 4 Nm.
  Note
  It is best practice to connect the ground circuit before making any PV circuit connections.
Starting with MPPT 1:
Note
If MPPT 1 is not wired first, it will not be possible to access that wiring terminal once conductors are connected to MPPT 2 or MPPT 3.
Warning
Before proceeding, confirm there is a lack of voltage on the PV wires.
1. Strip the conductor insulation so that the ends of the copper strands are visible.
2. Crimp the following insulated forked terminal onto the end of the conductor; a ratcheting die crimping tool is strongly recommended.
  - TE Connectivity P/N 165015 (4 - 6 mm² wire size)
  - Vogt P/N 3654c / 3655c (4 - 6 mm² wire size)
  CAUTION
  Forked terminals are required for PV wiring. Do not connect bare wires or any type of forked terminal other than those listed above due to increased risk of poor electrical connection.
  CAUTION
  Do not attempt to insert multiple forked terminals in a single wiring terminal. Only connect one forked terminal to each wiring terminal.
  CAUTION
  Do not attempt to connect multiple wires to a single forked terminal. If the system has more than three PV strings, combine strings upstream of Powerwall 3 and connect no more than three strings to the integrated DC isolator.
  Note
  Ensure the ends of the copper strands are visible at the bottom of the fork, indicating the conductor is making strong contact with the forked terminal.
3. Insert the forked terminal into the wiring terminal and, using a Philips PH2 torque screwdriver (see Required Tools for additional details), tighten the screw in the PV wiring terminal to 1.6 Nm.
  CAUTION
  Confirm the forked terminal is fully inserted before tightening the screw to avoid damaging the connector.
Repeat Step 5 for MPPT 2, then MPPT 3.
Figure 1. Powerwall 3 PV Wiring Connected to Integrated DC Isolator
CAUTION
Before energizing the system, use a multimeter to confirm the polarity of the PV strings is as pictured above (positive strings in bottom row of terminals, negative strings in top row of terminals). Reversed polarity of the PV strings may cause damage to the system.
Figure 2. Powerwall 3 PV Wiring and Protective Earth
CAUTION
All PV strings must pass through the integrated DC isolator. Do not attempt to connect PV strings via any other terminals. For more information on the integrated DC isolator, see Appendix F: Shutting Down Powerwall 3.
CAUTION
Any wire routing must be done through the wire management tabs at the top of the enclosure. Do not route loose wires through the front of the enclosure or over the Tesla Asset Controller.