Main service panel upgrades — the invisible prep that makes solar, storage and EVs possible.
If your home was built before 2000, there's a good chance your main service panel (MSP) is 100A or 125A — not enough capacity to safely add solar, a Powerwall and an EV charger without tripping breakers or violating NEC 705.12(B)(3)(2) busbar rules. Nuon Energy pulls the permits, coordinates SDG&E disconnect/reconnect, and upgrades your panel to 200A or 225A so every future addition drops in cleanly.
When you need an MSP upgrade
The National Electrical Code's 120% rule limits how much solar and battery power can back-feed a residential busbar. In practical terms, a 100A panel can only support a small solar array with no battery, and installing a Level 2 EV charger plus Powerwall on top of that is a non-starter. Upgrading to 200A (or 225A with a smart panel like Span or Lumin) gives you 40–80A of headroom for future additions.
Nuon Energy typically completes a residential MSP upgrade in a single day: SDG&E cuts service in the morning, our licensed electricians swap the panel, install a new meter socket if required, land all branch circuits on the new bus, coordinate the AHJ inspection, and SDG&E reconnects the same afternoon.
200A busbar supports up to 8kW+ of back-fed solar under NEC 705.
Whole-home backup requires enough amperage headroom for battery back-feed.
Level 2 chargers pull 32–48A continuous — panel must support the load.
AFCI/GFCI upgrades, SDG&E coordination, permit and inspection included.
What's included
- New 200A or 225A main breaker panel (Square D, Eaton or Siemens)
- Meter socket replacement if required by SDG&E
- Grounding electrode conductor and bonding to code
- AFCI and GFCI breakers per current CEC requirements
- Permit filing and AHJ inspection coordination
- SDG&E disconnect/reconnect scheduling
Signs you need one
- Panel labeled 100A or 125A
- Federal Pacific, Zinsco or Pushmatic panel (safety recall risk)
- Fuses instead of breakers
- No room for new breakers, or double-taps present
- Planning solar + battery + EV charger in the next 5 years
- Home built before 1990 with original electrical service
Ready for a free, no-pressure quote?
Tell us what needs cleaning. We usually respond same day, often within an hour.