NEMA 5-15 Receptacle

NEMA 5-15 is the ordinary grounded wall outlet found throughout North American homes and offices: 125 V, 15 A, three contacts (line, neutral, ground). Its plug is the familiar pair of flat blades plus a round grounding pin, and the matching 5-15R receptacle is what virtually every plug-in device on the continent expects. For anyone starting to mine at home, this humble outlet defines the playing field — and knowing its real limits is the first piece of electrical literacy a home miner needs.

The numbers that matter

A 15 A circuit at 120 V is nominally 1,800 W, but North American electrical code limits continuous loads (anything running three hours or more — which describes every miner) to 80% of the breaker rating. That leaves roughly 1,440 W of safe sustained draw per 15 A circuit, and that budget is shared with everything else on the same circuit: lights, chargers, the fridge two rooms over that happens to share the run. A 20 A circuit with 12 AWG wiring raises the continuous budget to about 1,920 W, though the 5-15 plug itself remains a 15 A device.

What actually mines on 120 V

Plenty, as it turns out — 120 V mining is home territory D-Central has worked in for years. A Bitaxe draws tens of watts; several of them, or a small farm of USB hashers, barely register on a household circuit. One tier up, S9-era Antminers have long been run on 120 V household power at reduced power profiles, turning a veteran machine into a practical space heater that pays part of its way. Even PSUs nameplated for higher-voltage operation are routinely run derated on 110–120 V in the field — a reality D-Central has verified across years of hands-on deployments, though output must be reduced accordingly and the per-circuit math above always governs. What does not work is a modern flagship ASIC at full power: a machine wanting 3,000 W+ is double the entire circuit budget and belongs on 240 V.

When the 5-15 runs out

Home miners hit two walls in quick succession: the 1,440 W circuit ceiling and the heat a single room can shed. The standard next step is a dedicated 240 V circuit, which doubles available power per ampere, lets wide-input PSUs run slightly more efficiently, and moves the machine onto hardware built for the job — typically a NEMA L6-30 locking receptacle or the range-style NEMA 14-50. Both are ordinary residential electrical work for a licensed electrician, and either transforms what you can run.

Safety notes worth taking seriously

One sibling worth knowing: the NEMA 5-20, the 20 A member of the same family. A 5-20R receptacle has a T-shaped neutral slot that accepts both 15 A and 20 A plugs, and it lives on 20 A circuits wired with 12 AWG copper — raising the continuous budget to roughly 1,920 W without leaving 120 V. Where a home panel has spare capacity, a dedicated 20 A circuit for the mining corner is a modest electrician visit that buys a third more headroom and, more importantly, isolates the load from the household's shared circuits. It is the sensible intermediate step before committing to 240 V work.

Most home-mining electrical incidents trace to the same few causes. A miner is a continuous, space-heater-class load: never run one on a circuit shared with other heavy appliances, and treat a repeatedly tripping circuit breaker as information, not an inconvenience to bypass. Worn receptacles with loose grip are heat sources under sustained load — replace any outlet a plug falls out of. Skip lightweight consumer power strips entirely; if you need distribution, use a properly rated unit. And feel the plug occasionally: a warm plug at modest load means resistance where there should be none. The 5-15 is a fine starting line for home hashing — respect its ceiling and it will serve; ignore it and it will remind you why the code exists.