5.8 How to upgrade a legacy NEM 1.0 / 2.0 system without losing grandfathering

California rule: expanding system capacity by more than the lesser of 10% or 1 kW forces the entire system onto NEM 3.0.

For legacy homeowners, this creates a deadlock:

• The original system is too small (builder-installed ones are often only 4–5 kW).
• They want a battery but want to keep NEM 2.0 export pricing.
• Their original contract is PPA / Lease, so they have no authority to modify it.

The clean solution: install a completely separate Non-export system —

• The new system uses a CT clamp to power household load only and never exports.
• The old system's NEM 2.0 grandfathering is not touched.
• The old system continues earning 1:1 credits for what it exports. The new system covers whatever the old one can't.
• California regulation explicitly permits this kind of "parallel but non-exporting" interconnection.

This is the only way to expand capacity without losing NEM 2.0 grandfathering.