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UPS (Uninterruptible Power Supply) | Legrand United Kingdom

Why is modular architecture important for UPS availability and risk mitigation?

Modular UPS systems with hot-swappable components allow rapid repair and easy upgrades, significantly reducing Mean Time To Repair (MTTR) and enhancing system availability. For example, a modular UPS with an MTTR of 0.5 hours and a Mean Time Between Failures (MTBF) of 1,000,000 hours can theoretically achieve "six-nines" (99.9999%) availability. This level of resilience greatly minimizes downtime risk and associated costs, offering a clear advantage over traditional monolithic systems with longer repair times and lower serviceability.

System Availability Levels and Downtime Impact

Availability (%)

Downtime per Year

Downtime per Month

Typical System Example

99.0 ("two nines")

~3.65 days

~7.2 hours

Non-critical IT systems

99.9 ("three nines")

~8.76 hours

~43.8 minutes

Standard enterprise IT systems

99.99 ("four nines")

~52.6 minutes

~4.38 minutes

High-availability systems

99.999 ("five nines")

~5.26 minutes

~26.3 seconds

Mission-critical infrastructure (common UPS target)

99.9999 ("six nines")

~31.5 seconds

~2.63 seconds

Best-in-class modular UPS systems

99.99999 ("seven nines")

~3.15 seconds

~0.26 seconds

Theoretical limit — extremely rare

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