PDU Sizing Mistakes We See in Facility Audits

Facility brochures list rack count and per-unit wattage. They rarely show the PDU nameplate or breaker schedule. That gap causes more deployment delays than faulty ASICs in our audit experience.

Mistake 1: Nameplate vs Sustained Draw

A PDU rated for 32 amps on a 220V circuit provides roughly 7 kW theoretical capacity. Mining units at 0.08 PH/s often draw 3.2–3.6 kW each at the wall. Two units per PDU sounds safe on paper. In practice, fan ramp during heat events pushes draw 10–15% above nominal for minutes at a time. Breakers trip. Hashrate drops fleet-wide.

We recommend planning for peak draw plus 15% headroom, not average draw.

Mistake 2: Phase Imbalance Across Rows

Operators sometimes fill phase A on row one and phase B on row two without checking cumulative load. The main panel sees balanced phases while individual branch circuits overload. We measure per-phase draw during audits and compare against the breaker schedule on the wall — they often disagree.

Mistake 3: Mixed-Vintage Units on One Circuit

Older 0.05 PH/s units drawing 2.8 kW share a PDU with newer 0.12 PH/s units drawing 3.8 kW. The circuit was sized for the older fleet. Adding new units without recalculating capacity is a common expansion error.

Mistake 4: Extension Cables and Splitters

Temporary cabling from initial setup becomes permanent. Voltage drop across undersized extension cords causes units to report power faults and throttle. We photograph every non-factory connection during audits.

What to Request Before Signing a Hosting Contract

Ask for the PDU schedule mapped to your proposed rack positions, not just total facility capacity. Request uptime logs from the last 90 days for the specific row you will occupy. If the operator cannot provide either, treat that as a risk signal.

Our Facility Site Audit includes a PDU risk summary with severity rankings. Most findings are fixable before hardware ships — if you catch them early enough.