Operator confirmed 2026-09-19 that fv-ml1 and the R420 running OPNsense are the
only loads on a dedicated 20 A circuit.
The governing number is 1920 W, not 2400: a GPU inference host running for hours
is a continuous load, so NEC's 80% rule applies. Worst case lands at ~1625 W
with the current caps -- about 85% of budget.
Measured via the BMC rather than assumed: 390 W instantaneous, 461 W max over a
2423 s sample, with GPUs at idle, giving a ~313 W non-GPU baseline.
Compare the GPU caps against the 300 W stock TGP, NOT the 325 W firmware
ceiling. The operator corrected this: 275 W across four cards saves 100 W, not
the 200 W you get by measuring against a number nobody would ever run at. Stock
300 W would put the circuit near 90%, which is not illegal but leaves nothing
for a heavier R420, PSU efficiency, or a warm day. Keep the caps.
The coupling matters more than the trip. OPNsense IS the Fountain Valley edge
and shares the breaker with the thing most likely to trip it, so an overload
takes the router with it and removes the remote path needed to diagnose or
power-cycle anything. fv-ml1's four PSUs do not help -- PSU redundancy protects
against a PSU dying, not against the circuit going away.
Three things are explicitly NOT measured and the file says so: fv-ml1 under real
4-GPU load, whether the BMC reports AC input or DC output, and the R420's actual
draw. Treat 1625 W as a floor.
Also corrects the hardware section, which claimed 2x GPUs. nvidia-smi reports
four.
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