Powerwall upgrades: does a legacy Solar Roof string layout limit future inverter/battery options (e.g., Powerwall 3) or require rewiring to preserve UL 3741 PVRSE compliance?
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So, your current setup might not work with Powerwall 3 unless the wiring is just right for its built-in inverter. A lot of installers skip the rewiring and just connect to your current inverters, but that can cut down on efficiency a bit. To make sure everything is up to code with your roof and Powerwall upgrade, it’s best to chat with Tesla-certified installers. They might need to tweak some things to meet all the requirements.
Want me to take a look at your string layout to see if you can add Powerwall 3 without rewiring?
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Yes, a legacy Solar Roof string layout can limit future inverter or battery upgrades like the Powerwall 3. If the system wasn’t originally designed to meet UL 3741 PVRSE (Photovoltaic Rapid Shutdown Equipment) compliance, upgrading may require rewiring or additional equipment (e.g., rooftop disconnects or compliant inverters) to meet current safety standards. Always evaluate compatibility and code compliance before upgrading.
You don’t necessarily have to rewire, provided the existing layout and components are already covered by a UL 3741-compliant PV Hazard Control System (PVHCS). However, the answer hinges on two key factors
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UL 3741 Certification for Your Existing Solar Roof Layout
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Compatibility with Future Equipment (e.g. Powerwall 3)