Home Mining Circuit Planner — 120V/240V Breaker & NEMA Outlet Calculator (NEC/CEC)

A 120V 15A circuit safely supplies up to 1,440 W of continuous mining load (NEC 210.20 / CEC Rule 8-104 80% rule); a 240V 30A double-pole circuit handles up to 5,760 W — use the planner below to calculate exact amperage draw, minimum breaker size, and the correct NEMA outlet configuration for your miner.

The NEC/CEC 80% continuous-load rule explained

Bitcoin miners run without interruption — that makes them continuous loads under both the U.S. National Electrical Code and the Canadian Electrical Code. Any load that operates for three or more hours without interruption is classified as continuous, and both codes impose the same constraint on it.

NEC 210.20(A) — Overcurrent protection for continuous loads

NFPA 70 (National Electrical Code) § 210.20(A) reads: “Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.” For a circuit that is exclusively a miner (all-continuous), this means the breaker rating must be at least 125% of the miner’s draw — or equivalently, the miner’s draw must not exceed 80% of the breaker’s rating. (NEC 210.19(A)(1) applies the same 125% factor to conductor sizing.)

CEC Rule 8-104(1) — Same constraint for Canadian installations

CSA C22.1 (Canadian Electrical Code) Rule 8-104(1) states: “The continuous load connected to a branch circuit shall not exceed 80% of the ampacity of the overcurrent device protecting the branch circuit.” The outcome is identical: a 30 A double-pole circuit may carry no more than 24 A (5,760 W at 240 V) from a continuous mining load. Canadian miners should also confirm with their provincial authority having jurisdiction (AHJ), as local amendments occasionally apply.

Formula reference

Wire gauge must be rated for the breaker, not the load. For a 30 A double-pole 240 V circuit use 10 AWG copper (minimum); for 50 A use 6 AWG. Longer runs may require one gauge larger to compensate for voltage drop — confirm with your electrician. See ASIC miner power requirements: the North American 120 V & 240 V guide for full wiring guidance.

Standard North American mining circuit configurations

The table below covers the most common configurations for home and small-hashcenter setups. All loads are continuous; breaker ratings reflect the 80% rule (draw amps × 1.25, rounded up to standard size).

TDP values shown as examples. Always use the manufacturer nameplate rating. Neutral conductor (NEMA 14-series) required only if your PDU or PSU explicitly requires it — most ASIC PSUs do not. Wire gauge: 12 AWG for 20 A; 10 AWG for 30 A; 6 AWG for 50 A; 4 AWG for 60 A — minimum copper, 60°C rating or better.

120 V vs 240 V for home Bitcoin mining

Most residential Bitcoin miners in North America use 240 V split-phase power for anything above roughly 1,500 W. The reasons are practical:

• Lower current for the same wattage. A 3,500 W miner draws 29.2 A at 120 V but only 14.6 A at 240 V. The 120 V load requires a 40 A breaker (to meet the 80% rule) versus a 20 A double-pole at 240 V — significantly cheaper wiring and a common breaker size.
• Efficiency. Most ASIC PSUs have higher efficiency at 240 V (typically 92–96% vs 88–92% at 120 V, manufacturer-specific). The heat output difference is small but measurable over months of operation.
• Most residential panels already have 240 V available. North American split-phase panels feed 240 V from any two opposing breaker slots. Adding a double-pole breaker is usually straightforward if panel capacity exists.
• 120 V is fine for ultra-low-draw devices. Bitaxe, NerdAxe, and similar open-source miners operate happily on a standard 120 V 15 A or 20 A circuit, often sharing that circuit with other devices given their minimal draw.

Full wiring guidance — including panel sizing, sub-panel decisions for multi-miner setups, and Canadian-specific CEC considerations — is covered in the North American ASIC power guide. For operating cost modelling, pair this planner with the power cost calculator and provincial electricity rates.

Frequently asked questions

What is the NEC 80% rule and why does it apply to Bitcoin miners?

NEC 210.20(A) (and its Canadian equivalent, CEC Rule 8-104(1)) requires that the overcurrent protection device on a branch circuit be rated for at least 125% of any continuous load connected to it — a continuous load being one that runs for three or more hours without interruption. Bitcoin miners run 24/7, so they are always continuous loads. The practical effect is that you must size the breaker to at least 125% of the miner’s draw current, which means the miner’s draw must not exceed 80% of the breaker’s ampere rating. A 20 A breaker is therefore limited to 16 A (3,840 W at 240 V) of continuous mining load, not the full 20 A.

Can I plug my ASIC miner into a regular wall outlet?

Standard North American 120 V outlets are rated for 15 A (NEMA 5-15R) or 20 A (NEMA 5-20R), allowing a maximum continuous mining draw of 1,440 W or 1,920 W respectively. Most full-size ASIC Bitcoin miners draw 2,000–5,000 W and require a dedicated 240 V double-pole circuit — they cannot run on a standard 120 V household outlet. Check your miner’s nameplate wattage and verify with the calculator above. Small open-source miners like the Bitaxe (~5–35 W) are designed for standard 120 V outlets and present no circuit concerns.

What wire gauge do I need for a 240 V mining circuit?

NEC Table 310.12 and CEC Table 2 specify minimum conductor ampacities. Common pairings for mining circuits (60°C rated copper, non-derating conditions): 20 A breaker → 12 AWG minimum; 30 A → 10 AWG; 40 A → 8 AWG; 50 A → 6 AWG; 60 A → 4 AWG. Longer cable runs, conduit fill, or higher ambient temperatures may require the next heavier gauge. This is one of several reasons a licensed electrician should review any dedicated mining circuit — the planner above calculates breaker size but does not account for conductor derating.

Do I need a dedicated circuit for my miner?

Yes, for any load above about 500 W. The 80% rule applies to the total continuous load on a circuit — if your miner shares a circuit with a refrigerator, computer, or lights, the combined draw must still stay within 80% of the breaker’s rating. In practice, any ASIC miner should be on its own dedicated branch circuit. This also makes troubleshooting and metering far simpler, and protects other equipment from power fluctuations caused by the miner’s startup inrush current (typically 2–3× running current for 100–200 ms on power-up).

What is the difference between NEMA 6-30R and NEMA 14-30R?

Both are 240 V 30 A outlets, but they differ in conductor count. NEMA 6-30R carries two 120 V hot legs and a ground — no neutral wire. NEMA 14-30R carries two hot legs, a neutral, and a ground (four conductors). Most ASIC miner power supplies do not require a neutral conductor, so NEMA 6-30R is the standard choice for mining circuits. Some PDUs (Power Distribution Units) or older miners specify a neutral — check your PSU’s technical documentation. Your electrician will know which to install based on the actual equipment.

How do I calculate the total panel capacity needed for multiple miners?

Add the TDP wattages of all miners you plan to install, multiply by 1.25 (the continuous-load factor), then divide by your panel voltage to get the total breaker amperage required. For example, four miners at 3,500 W each = 14,000 W × 1.25 = 17,500 VA ÷ 240 V = 72.9 A. Four dedicated 20 A double-pole circuits (80 A total) would handle that load. Most residential 200 A panels can support two to four mining circuits before you begin encroaching on household load headroom — use the mining profitability calculator alongside these numbers to evaluate whether your available capacity is worth building out. For larger deployments, consider a dedicated sub-panel.

Related tools and guides

• ASIC Miner Power Requirements: The North American 120 V & 240 V Guide — wiring, panel sizing, sub-panels, and CEC/NEC reference
• Bitcoin mining hardware — nameplate TDP and specifications for current ASIC models
• Power cost calculator — estimate monthly electricity cost once your circuit is sized
• Mining profitability calculator — model full-stack economics including power overhead
• Canadian electricity rates by province — kWh rates across all provinces and territories
• Bitcoin miner space heater BTU calculator — model heat output for heat-reuse mining setups
• Bitcoin mining heat reuse guide — whole-house and room heating with mining hardware
• Bitaxe open-source miner hub — hardware options for 120 V-friendly open-source solo mining
• Open-source miners comparison — Bitaxe, NerdAxe, NerdQAxe and community hardware
• Energy for compute — Bitcoin mining’s power advantage for AI and sovereign infrastructure