Reading a Miner Nameplate: Wattage vs. Wall Draw

Every miner above 0.05 TH/s ships with a wattage figure on the housing label. Operators routinely size PSUs and breakers to this number and encounter problems within weeks.

Nameplate vs. Reality

The printed wattage represents chip draw under factory test conditions — typically 25°C ambient, stable 240V input, and fresh thermal paste. Your installation differs on all three counts.

Our bench logs show actual wall draw running 8–15% above nameplate in Korean summer conditions. A unit rated at 3,250W frequently pulls 3,520W at the meter during sustained operation.

PSU Sizing Formula

Take the nameplate wattage, multiply by 1.15 for summer margin, then divide by your measured voltage and power factor (typically 0.95–0.98 for modern PSUs). Round up to the next standard PSU capacity.

For a 3,250W nameplate miner:

• Adjusted draw: 3,250 × 1.15 = 3,738W
• At 220V and 0.97 PF: 3,738 / (220 × 0.97) ≈ 17.5A

A 15A circuit cannot sustain this. You need a 20A dedicated breaker with headroom, or you accept throttling through firmware — which reduces your effective hash rate below the 0.05 TH/s floor you are targeting.

The 80% Breaker Rule

Electricians in Korea generally recommend loading breakers to no more than 80% of rated capacity for continuous loads. Mining qualifies as continuous. A 20A breaker should carry no more than 16A sustained — plan your rig count accordingly.