What an AIC Letter Is
An AIC letter tells you how much fault current is available at your electrical service. AIC means “Available Interrupting Current.” PG&E calculates it for your address. The City uses it to make sure your equipment can safely handle a worst-case fault.
Think of the AIC value as a “stress number.” Your main breaker, meter-main, switchboard, or panel must be rated to stop that stress. If the letter says 16,000 amps, your equipment cannot be rated for 10,000 amps. The rating must meet or exceed the number on the letter.
This is why inspectors ask for the AIC letter on service work. It protects people and property. It also keeps your project code-compliant and ready for a green tag.
When Oakland Requires an AIC Letter
Oakland requires an AIC letter before inspection when your project touches service equipment. If you are replacing a main panel, relocating a meter, increasing service size, or adding service-side gear, plan on getting the letter. If you do not have it, your inspection can be delayed.
For small, simple projects that do not touch the service, the City may not need it. Swapping a light fixture like-for-like is different from changing a meter-main. But once you touch the service, the AIC letter becomes part of the package. The safest plan is to ask early and avoid surprise holds.
Quick Scenarios: Do You Need an AIC Letter?
| Project Scenario | AIC Letter Needed? | Why |
|---|---|---|
| Main service panel replacement (same size) | Yes | Inspector must verify equipment AIC rating matches available fault current. |
| Service upgrade (100A → 200A or higher) | Yes | Higher load and new gear require rating checks and a utility release. |
| Meter relocation or service re-route | Yes | Service work requires a release and equipment rating confirmation. |
| New feeder to a detached garage with a subpanel | Often | Depends on whether service equipment is changed. Ask the City or your contractor. |
| Like-for-like receptacle or switch replacement | No | Not service work. Typical maintenance only. |
| EV charger branch circuit from existing panel | Usually no | Panel capacity still matters, but service-side work is not typical here. |
| Battery or generator with new service equipment | Yes | Interconnection and service changes bring rating and release checks. |
How to Read the AIC Number
The letter shows the fault current at your service in amperes. Common values include 5kA, 10kA, 14kA, 22kA, and higher. Your main breaker or switch must have an interrupting rating that meets or exceeds the letter’s value.
If the letter says 14kA and your main breaker is 10kA, that is not acceptable. You must upgrade to a device rated at least 14kA, often 22kA. Some systems use series-rated combinations. Those need listed pairings and labels to pass. Your electrician can check listings and labeling.
Simple Cross-Check Example
| AIC Letter Value (Example) | Main Breaker / Switch Rating | Pass? | Notes |
|---|---|---|---|
| 5,000 A | 10kAIC | Yes | Device rating exceeds available fault current. |
| 14,000 A | 10kAIC | No | Upgrade needed or use a listed, labeled series combination. |
| 22,000 A | 22kAIC | Yes | Matches the AIC letter exactly—acceptable. |
| 28,000 A | 22kAIC | No | Rating is below the available fault current—upgrade required. |
Step-by-Step: How to Get an AIC Letter from PG&E
Requesting an AIC letter is straightforward if you have the right info ready. Follow these steps and you will avoid most delays. If you prefer, we can request it for you.
- Collect project details. Get the service address, meter number (if known), existing service size, and proposed scope (panel swap, upgrade, meter move, etc.).
- Call PG&E’s Building & Renovation Services. Use 1-877-743-7782. Say you need the Available Interrupting Current (AIC) for your service.
- Provide your details. Give the address and scope. Ask for the AIC letter or confirmation in writing.
- Save the letter. Keep the PDF or email. Place a copy in your permit folder for the City inspector.
- Verify your gear. Check that your main breaker, meter-main, or switchboard is rated to the AIC letter or higher.
- Book inspection only after you have it. This prevents holds on service releases and green tags.
Oakland’s Inspection Flow and the AIC Letter
In Oakland, the AIC letter is tied to the green tag. The green tag is the City’s release to the utility. Without the letter, the City cannot release your service after a panel change or upgrade. The result is a delay that can stop your project on cut-over day.
To see the full path from rough to final to green tag, review our inspection guide. It explains what to prepare at each step and how to pass the first time. Use this link when you plan your cut-over: Oakland green tag inspection steps.
Documents Inspectors May Ask For
On service work, inspectors often ask for three things. First, the permit and job card. Second, the AIC letter from PG&E. Third, the label or documentation showing your device rating or series combination. On some jobs, a PG&E Confirmation of Discussion (COD) is also requested at service equipment.
Keep these items printed or on a tablet. Label your service equipment clearly. Make access easy. Good labeling and neat work help inspections go faster and smoother.
Residential vs. Commercial Projects
Home projects often involve main panel replacements or upgrades to support EV chargers, heat pumps, or kitchen remodels. These touch the service and will need the AIC letter. The City also checks working clearances, grounding, and labeling during inspection.
Commercial projects add more layers. Think switchboards, CT cabinets, larger services, and lighting controls. These jobs often require plan review and tighter coordination with the utility. If you manage a tenant improvement or multi-family property, expect more documents and more scheduling steps.
For a single point of contact on business projects, see our experienced Oakland electricians for commercial projects page. We handle submittals, shutdowns, and service releases.
Common Mistakes (and How to Avoid Them)
The most common mistake is scheduling a service inspection without the AIC letter. The second is installing gear with a rating below the AIC value. The third is missing labels or documents on site. All three cause holds and extra visits.
Avoid these issues with a simple checklist. Get the AIC letter first. Match your device ratings. Bring the permit, job card, and documents to the inspection. If your project is on a tight timeline, call early and confirm dates with both the City and PG&E.
Helpful Contacts (Click to Call)
For inspections in Oakland, call the Building Inspections desk at (510) 238-3444. For general Planning & Building questions, call (510) 238-3443. For zoning, call (510) 238-3911. For permit help, call (510) 238-3891.
For PG&E Building & Renovation Services, call 1-877-743-7782. For general customer service, call 1-877-660-6789. If your project needs trenching, call 811 two working days before you dig.
Why Work With Momentum Electrical Contractors
We handle AIC letters, permits, and inspections from start to finish. Our team requests the letter, verifies equipment ratings, and prepares the site for inspection. We also coordinate with PG&E on shutdowns and cut-overs to ensure your project doesn’t stall at the final step.
Need help now? Call (415) 559-3333 . Want to explore your options first? Visit a trusted Bay Area electrical company to learn more about our services from an Oakland CA electrical contractor for homes. For a full permit overview, see our Oakland electrical permit guide.
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