2025-06-03

Powerwall+ Lockout/Tagout

Hazards: Arc flash and electrical shock.

Warning IconA warning icon, calling your attention to a possibly risky situation
Warning
This procedure is to be done before actively working on a Powerwall+ to prevent arc flash and electrical shock hazard.

Tools and Equipment:

  • CAT 2 arc-rated long-sleeved shirt (tucked in) and arc-rated pants
  • Safety Glasses (ANSI Z87 rated)
  • Class 0 insulated electrical gloves with leather protectors or equivalent protectors (ANSI A4 cut resistant, ANSI A3 abrasion resistant, ASTM CAT2)
  • Safety rated shoes with leather upper
  • Class IV Multimeter (rated for equipment voltage)
  • Proving Unit (Fluke PRV240 or equivalent)
  • T20 Torx driver
  • Lockout/Tagout equipment:
    • Simple LOTOV: One person, One individually controlled lock, One tag with name and contact information, and breaker clamp
    • Complex LOTOV: A complex LOTOV is required for multiple energy sources and multiple disconnecting means.
    • Individually controlled locks & tags
    • Breaker clamps
    • Lock box or tree hasp
      • The LOTOV Lead will be the person designated by the service visit assignment.
      • The LOTOV Form is required for Tesla complex LOTOV.
      • All individuals working on equipment are required to be included in the LOTOV.
Overview:
Residential systems are highly variable, de-energization procedures may differ from site to site depending on the hardware the site has. Ensure you understand the site architecture and the required de-energization procedure before performing any work All steps of this procedure may not be applicable for all systems due to this variability, but any applicable steps should be performed. If you do not understand which steps are applicable please escalate to your manager for assistance.

Figures showing variations of systems containing a Powerwall+ (non-exhaustive)

  1. The Inverter component of the Powerwall+ system has 3 sources of incoming power that must be isolated to perform work on the unit: AC Grid power, DC PV Power, and AC Powerwall power.
    Warning IconA warning icon, calling your attention to a possibly risky situation
    Warning
    While de-energizing the system the proper PPE must be worn to protect against the electrical hazards that are present. Ensure you have the proper PPE and are wearing it correctly.
  2. Turn off the system via the setup app and ensure the app reflects that it's been turned off.
    Informational PurposesAn informational icon, calling your attention
    Note
    Turning off via the system shutoff app will power down all system components, this is important when a system has multiple Powerwalls or other interconnected units.
  3. De-energize the Powerwall+ by turning off the switch on the side of the Powerwall unit.
  4. Isolate the Powerwall+ from the load center/grid connection by disabling the breaker upstream of the PVI. Apply a breaker clasp and LOTO to the breaker.
    Informational PurposesAn informational icon, calling your attention
    Note
    This breaker may be in a backup load center, a main load center, or in a backup gateway. The breaker that is directly upstream of the Powerwall+ should be isolated or deenergized.
    Warning IconA warning icon, calling your attention to a possibly risky situation
    Warning
    All individuals working on the Solar Inverter system must apply a Lock and Tag. When more than one individual is working on the Solar Inverter system, all individuals must also sign on and off when applying and removing their lock. Use the LOTOV Form linked here.
  5. Isolate the PVI (Photovoltaic Inverter) from the solar power. If there is a shutoff switch turn it off and apply a LOTO.
    Informational PurposesAn informational icon, calling your attention
    Note
    This may not be present in all systems. If present, this should only be done AFTER the Powerwall switch has been turned off. Systems using MCIs (Mid-Circuit Interrupter) will be disconnected when the system is disabled in the setup app and the Powerwall turned off.
  6. Open the Solar Inverter cover by depressing the latch and opening the door. Remove the ground wire from the door by unscrewing the nut holding it. Slide the door to the right to remove it from the hinges and set it aside.
  7. Prepare a multimeter to check the PVI for dead.
  8. Put on Class 0 insulated electrical gloves with leather protectors or equivalent protectors (ANSI A4 cut resistant, ANSI A3 abrasion resistant, ASTM CAT2). These gloves will be worn until Live- Dead – Live is completed and 0 voltage is verified.
  9. Set the multimeter (rated for equipment voltage) to measure AC voltage, and measure a known AC source such as a Proving unit (Fluke PRV240 or equivalent). Ensure the measured reading matches the known value. Switch both the multimeter and the proving unit to DC voltage and repeat the test. Again ensure the readings match expected. If either reading does not match what is expected do not continue. Use another multimeter and repeat the test.
  10. Set the multimeter to measure AC voltage. Test the AC voltage between the L1, L2, N, and Ground relative to each other. Check phase to phase, phase to neutral, and phase to ground. No voltage should be more than 0V before proceeding with service. If you detect any AC voltage, STOP and determine the cause. Do not proceed with work until the voltage can be verified to be 0. Reach out to a supervisor if necessary.
  11. Set the multimeter to measure DC voltage. Test the DC voltage on each + PV string relative to their corresponding -, as well as to ground. No voltage should be more than 0V before proceeding with service. If you detect any DC voltage, STOP and troubleshoot before continuing.
  12. Switch the multimeter back to AC voltage mode. Test the Powerwall connection AC voltage. Remove the harness from the connector and probe inside of the connector. Measure phase to phase, phase to neutral, and phase to ground. Repeat the same process with the harness itself, measuring phase to phase, phase to neutral, and phase to ground. No voltage should be more than 0V before proceeding with service. If you detect any AC voltage, STOP and troubleshoot before continuing.
  13. Set the multimeter (rated for equipment voltage) to measure AC voltage, and measure a known AC source such as a Proving unit (Fluke PRV240 or equivalent). Ensure the measured reading matches the known value. Switch both the multimeter and the proving unit to DC voltage and repeat the test. Again ensure the readings match expected. If either reading does not match what is expected do not continue. Use another multimeter and repeat the test.