share of impactful outages caused by power (most often UPS) — the leading cause; 45% of 2025 outages, restated in Uptime's 2026 report and down from 54% in 2024
45%observed
| Value kind | observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range. |
|---|---|
| Caveat | Respondent-based survey result (Uptime Institute, Annual outage analysis 2026, Figure 4, n=96, 'primary cause of your most recent impactful incident'), not an event-by-event census of the industry. The 2026 report does republish 45% for 2025 outages — down from 54% in 2024 — and reports a fifth consecutive year of declining per-site outage frequency with the pace of improvement slowing. Uptime attributes part of the fall to electrical upgrades and part to other causes rising (fire-suppression share up six points year-over-year). |
| As of | 2025 |
| Source | Uptime Institute, Annual Outage Analysis 2026, Figure 4 (n=96) — 45% is the 2025 outage year, restated there and down from 54% in 2024. · Annual outage analysis 2026, Figure 4 (printed p. 11) |
| Review | checking…review by 2027-05-01 · standard cadence |
| Recorded changes | last 2026-09-16 · 4 revisions tracked |
| Claim id | share-of-impactful-outages-caused-by-power-most |
Where the guide uses it
- 0.5 Reliability, Redundancy & Availability: The Design-Basis Primer
- 12.1 Resilience Standards, Redundancy Topologies & Fault-Domain Engineering
- 14.7 Capacity, Power & Thermal Management in Operation
- 14.12 Operational Procedures, Change Management & Human-Error Control
- 14.14 Continuous & Re-Commissioning on a Live Campus
← Full numbers register — every date-stamped figure in the guide, with revision history.