When your development project needs PG&E to extend electric service — which is virtually every project — the cost allocation, design responsibility, and timeline depend on which tariff rule applies. Rule 16, Rule 20, and Rule 21 are the three PG&E tariff rules that govern electric line extensions and relocations. Confusing them leads to budget surprises and schedule delays.
Rule 16: Line Extensions for New Service
Rule 16 governs the extension of electric distribution facilities to serve new customers. This is the rule that applies to virtually every new development project — subdivisions, commercial buildings, multifamily housing, schools, and industrial facilities.
Who pays: The developer pays for the distribution line extension through an advance payment to PG&E. PG&E designs and constructs the extension using PG&E's standard materials and specifications. The developer gets a refund of a portion of the advance over a period of years as new customers connect and begin paying for electric service (the "revenue credit" mechanism).
What it covers:
- Extension of primary distribution lines (underground or overhead) from the nearest adequate source to the project
- Installation of transformers, switchgear, and service panels at the project
- Secondary distribution to individual service points
- Trenching and conduit (in some cases the developer provides the trench and conduit; in others PG&E includes it in the advance)
The process:
- Developer submits a project inquiry to PG&E's new business/major projects group, including load estimate, site plan, and phasing schedule.
- PG&E reviews and issues a preliminary cost estimate and schedule.
- Developer executes an Electric Service Agreement and pays the advance (or posts a bond/letter of credit).
- PG&E designs the extension (or reviews the developer's engineer's design, depending on the scope).
- Developer installs conduit, vaults, and transformer pads per PG&E's specifications (the "developer-installed" portion).
- PG&E installs cable, transformers, and metering equipment.
- PG&E energizes the system and provides permanent service.
Timeline: From project inquiry to energization: 6 to 18 months for a typical commercial project; 12 to 36 months for a large subdivision with multiple phases. The longest lead items are usually the preliminary engineering estimate (6-12 weeks), the detailed design (8-16 weeks), and equipment procurement (transformers can have 16-52 week lead times).
Rule 20: Conversion of Overhead to Underground
Rule 20 governs the conversion of existing overhead electric facilities to underground. It is not for new service — it is for replacing existing overhead lines with underground lines. There are three sub-rules:
Rule 20A: Utility-Funded Conversion
PG&E funds the conversion using credits allocated to municipalities. Cities apply for Rule 20A credits and prioritize which overhead lines to convert. The conversion is at PG&E's expense (ultimately ratepayer expense). This applies to public thoroughfares, not private development.
Developers cannot use Rule 20A for their projects. However, if a municipality has Rule 20A credits available and the developer's frontage is on the priority list, the overhead-to-underground conversion on the public street may be coordinated with the development, saving the developer the cost of the frontage conversion.
Rule 20B: Developer/Property Owner-Funded Conversion
The developer or property owner requests and pays for the conversion of overhead facilities to underground. This is common when a development project has overhead lines running through or along the property that must be relocated underground as a condition of approval.
Who pays: The developer pays the full cost of the conversion, including removal of the overhead facilities, installation of underground conduit and vaults, and new underground cable. No revenue credits or refunds apply. Cost: $200 to $500+ per linear foot of overhead line converted, depending on complexity.
Rule 20C: Municipal-Funded Conversion
The municipality funds the conversion when it is in the public interest but no Rule 20A credits are available. The municipality pays PG&E for the work.
Rule 21: Interconnection for Generation
Rule 21 governs the interconnection of generating facilities (solar PV, wind, battery storage, co-generation) to PG&E's distribution system. If your project includes rooftop solar, a battery energy storage system (BESS), or any other on-site generation that will be connected to the grid, Rule 21 applies.
The process:
- Developer/owner submits an interconnection application to PG&E.
- PG&E conducts an initial review to determine if the generation can be accommodated on the existing distribution system.
- If the system can accommodate the generation, PG&E issues a permission to operate (PTO) after the installation is inspected and approved.
- If the system cannot accommodate the generation (because it exceeds the hosting capacity of the local distribution circuit), PG&E conducts a detailed study and identifies the upgrades needed. The developer pays for the upgrades.
Timeline: Simple rooftop solar (under 25 kW) on a residential project: 2 to 4 weeks for PTO after passing inspection. Commercial solar (25 kW to 1 MW): 4 to 12 weeks. Large systems (over 1 MW) or systems requiring distribution upgrades: 6 months to 2+ years.
Which Rule Applies to Your Project?
| Situation | Applicable Rule |
|---|---|
| New commercial building needs electric service | Rule 16 |
| New subdivision needs distribution line extension | Rule 16 |
| Existing overhead lines on property must go underground | Rule 20B |
| City wants to underground overhead lines on Main Street | Rule 20A (if credits available) or 20C |
| Project includes rooftop solar | Rule 21 (plus Rule 16 for the base service) |
| Project includes battery storage connected to grid | Rule 21 |
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