Short answer
A Public Safety Power Shutoff (PSPS) is when an electric utility deliberately de-energizes lines during high wildfire risk weather. For a data center, PSPS exposure means your utility feed can be turned off on purpose, for hours or days, even if your site never sees a fire. Screen for it by checking whether the site's serving lines run through utility-designated high fire risk areas, how often those circuits have been shut off before, and whether your backup power and fuel plan can carry a multi-day event.
Key terms
PSPS: a planned, preventive de-energization by the utility to reduce the chance that its equipment starts a wildfire.
High fire threat area: a zone designated by a utility or regulator where wildfire risk is elevated. In California these are mapped by the state utility commission; other states and utilities publish their own maps.
Wildfire mitigation plan: a utility filing describing how it manages wildfire risk, including when and how it uses shutoffs. Several western states now require them.
Serving circuit: the specific lines and substations that deliver power to your site. PSPS risk follows the circuit, not just the parcel.
Why this is different from wildfire hazard screening
Natural hazard screening asks whether fire could reach the site. PSPS screening asks whether fire risk somewhere along your supply path could cause the utility to cut power to you. A parcel in a low-risk valley can still be fed by lines crossing high-risk terrain.
The screen
| Step | What to check | Where to look |
|---|---|---|
| 1. Map the feed | Which substation and lines will serve the site | Utility interconnection discussions, load study |
| 2. Overlay risk zones | Do those lines cross designated high fire risk areas | Utility and regulator fire threat maps |
| 3. Check history | Have those circuits been de-energized before, and for how long | Utility PSPS event reports and regulator filings |
| 4. Read the plan | How the utility decides on shutoffs and what customers get notice | Utility wildfire mitigation plan |
| 5. Size resilience | Can backup generation and fuel cover a multi-day outage | Your design basis and fuel supply contracts |
Decision rules
Treat PSPS as an availability input, not a rare event. In shutoff-prone service areas, plan for it seasonally.
Circuit beats parcel. Always evaluate the transmission and distribution path, not only the site location.
Fuel autonomy has to match event length. Backup generators sized for short grid blips may not cover a multi-day shutoff without refueling, and refueling access can be limited in the same weather.
Ask about hardening plans. Undergrounding, sectionalizing, and grid hardening on your circuit can change exposure over time. Get the utility's stated plan in writing where possible.
Reflect it in underwriting. Lenders and tenants may ask about PSPS exposure. Have the evidence ready.
Red flags
Serving lines cross mapped high fire risk terrain
Prior shutoff events on the same circuit
Single radial feed with no alternate path
Backup fuel plan assumes easy delivery during red flag conditions
No utility guidance on notice or restoration practice
How Build approaches it
Build sources sites and then validates power deliverability, which includes looking at the path power takes to the site and the risks along it. For sites in wildfire-prone regions, that validation surfaces PSPS exposure before you commit, so the sites you get are ones where both energization and reliability hold up. Build then helps bundle the design and specialist services to plan resilience for the sites that move forward.
Checklist
Serving substation and lines identified
Lines overlaid on high fire risk maps
Shutoff history for those circuits reviewed
Utility wildfire mitigation plan read
Backup generation and fuel autonomy sized for multi-day events
Hardening or alternate feed options documented