Shop power planner

Choose the electrical system: US (120/240 V split-phase, with 208, 240 and 480 V three-phase circuits; NEC wire tables and inverse-time breakers) or UK / EU (230 V single-phase and 400 V three-phase; mm² cable and type B, C or D MCBs). Each keeps its own plan. Lengths are in feet or metres, shared with the other workshop tools.

Circuits and machines — each circuit has its supply, leg or phase, breaker, curve type (UK/EU), wire size and material, wiring method (NM cable or THHN in conduit, US) and one-way length. Add machines from the library — table saws (1¾, 3 and 5 hp three-phase), dust collectors and cyclones, compressors, planer, jointer, bandsaw, router, lathe on a VFD, MIG, TIG, stick and plasma with their duty cycles, kilns, CO₂ and diode lasers, 3-D printers, heaters, lights — or anything else. Each has its running current at the circuit’s voltage, power factor, starting surge (multiple of running current), run-up time, kind, and whether it runs continuously (3 hours or more). Tick On for what runs together.

What can run at once — every circuit with the ticked machines running: running current, the load on the breaker (with the US 125 % continuous rule), real power, voltage drop, the wire’s rating, and for each motor what happens when it starts with the others running — peak current, the voltage dip, and whether it is clear of the breaker’s trip curve, may trip, or will trip.

Load schedule — the service or subpanel rating, the connected load (and the NEC way: plus 25 % of the largest motor and of continuous loads), the current on each leg or phase now, and a table of every circuit and its loads to print or download as CSV.

Method — a three-phase current calculator and how each check is made.

Current is VA ÷ V for single-phase and VA ÷ (√3·V) for three-phase; real power is that times the power factor. The US continuous rule is NEC 210.19(A)/210.20(A): breaker ≥ 125 % of continuous plus 100 % of other loads. BS 7671 has no 80 % rule; it asks for Ib ≤ In ≤ Iz. Starts are checked against the breaker’s instant-trip band (type B 3–5 ×, C 5–10 ×, D 10–20 ×, US thermal-magnetic roughly 6–10 ×) and a thermal band fitted to IEC 60898 and UL 489. Voltage drop is 2·I·R·L (or √3·I·R·L for three-phase) with resistance from NEC Chapter 9 Table 8 or IEC 60228. Welders use I₁ × √duty (NEC 630.11). Real breakers vary from these curves; a "may trip" is a reason to look closer.

For wire gauge and ampacity tables see the electronics handbook. A compressor comes over from the compressed air sizing tool, and a collector’s size from the dust collection planner. What the shop costs to run is in the energy usage analyser; heating it, in the heat loss calculator. Settings for the welder are in welding settings and reference, and a kiln’s firing schedule and energy cost in the kiln and firing calculator.

Any current browser, on a phone or a desktop. Print prints the load schedule alone.

Everything runs in your browser and your plan is kept in its local storage. Nothing is sent anywhere; Share puts the plan in the link itself.