Why Single-Rail PSUs Fail Korean Summer Loads

Korean residential grids experience predictable voltage depression between 6 PM and 11 PM during summer. Air conditioning load across apartment complexes pulls neighborhood voltage down by 3–8 volts compared to morning readings.

What We Tested

We ran four common miner configurations at our Jung-gu lab while simulating voltage drop using a variable autotransformer. Each unit was rated above 0.05 TH/s. We compared single-rail and dual-rail PSUs at identical hash rates.

Findings

Single-rail units showed 12V rail sag to 11.2V at 215V input — below the ASIC tolerance threshold for two of four miners tested. Dual-rail designs maintained 11.6V or higher under the same conditions.

The critical factor was not total wattage capacity but how that capacity distributed across rails during the brief power spikes that occur when a new block is found and the ASIC briefly increases clock draw.

Practical Recommendation

If your mining room shares a building transformer with heavy AC load, budget for dual-rail PSUs rated at least 20% above your miner’s nameplate wattage. Measure your evening voltage with a plug-in meter for one week before selecting hardware.

Cable Factor

Undersized extension cords compounded the sag problem. A 16 AWG cord over three meters added an additional 0.3V drop under load. Use the gauge our PSU pairing reports specify — do not substitute based on what is in stock at the hardware store.