N+1
A component group or capacity arrangement with N units required for the declared design load plus one spare unit. N+1 describes provisioned capacity, not guaranteed tolerance of every failure or maintenance event or an availability outcome.
Current numbers
OEM/test-specific transientloss-of-cooling thermal-trip window for 1 kW+ GPUs — UPS-backed pumps + N+1/2N rejection mandatory
Project-specific BOM/TCO premiumMEP-scope construction-cost swing of 2N over N+1 for the same usable load; 2N strands ~50% of installed capacity
~80 MVA x3typical HV/MV transformer unit, N+1, to serve ~150 MW peak; ~10% MVA cushion over MW