Power budget (breaker caps)
Servers and switches all draw power, and that power comes through a rack circuit with a hard ceiling. The garage rack runs on a 3kW budget; a standard rack is 8kW. Add up the draw of everything in a rack and you have to stay under its breaker — packing in one more host because there's a free U slot is exactly how you trip it.
When sustained draw passes the cap, the breaker trips and the WHOLE rack goes dark — every server and every switch in it, all at once, for hours while it cools off. The buy panel warns you before you cross the line, but it's your job to plan headroom. Power is the most unforgiving constraint in the game precisely because it takes out healthy hardware as collateral.
Detailed explanation
Per-rack budget is the sum of power_w across mounted hosts and switches against the rack's power_budget_w (3kW garage / 8kW standard). Buy-time validation warns at the 95% threshold. Sustained draw over the cap rolls a per-BillingTick trip probability; a RackBreakerTripped incident cascades every host AND switch in the rack offline for several sim-hours.
Power isn't only the circuit — the PSU components inside each host age and fail on their own health curve, and a spare PSU has to come from the same kind family (wattage / form-factor compatible). The grounded power-budget probe reports current draw vs cap per rack; the open-incidents probe surfaces any live breaker trip or PSU failure. Plan circuit headroom AND keep spare PSUs on the shelf.