Methodology

How results are calculated

PowerTotals uses deterministic arithmetic, explicit units, visible assumptions, and source-backed scientific constants. Values are rounded only for display; calculations retain full JavaScript number precision.

Every interactive result is rendered as ordinary text in the document. Diagrams explain relationships but never replace the numeric result.

Educational use and safety limits

PowerTotals provides educational calculations and does not determine electrical-code compliance. It does not size breakers, verify conductor ampacity, select grounding or bonding conductors, calculate code box fill, perform arc-flash analysis, design short-circuit protection, size services, or provide permit advice.

Voltage-drop wire selection searches only for the smallest supported conductor satisfying the user's resistive drop target. It does not verify ampacity, insulation, terminations, overcurrent protection, installation method, or adopted code.

Units and precision

• Exact conversions are used where definitions are exact, including 1 ft = 0.3048 m and 1 in = 25.4 mm.
• AWG diameter and area are computed from the standard mathematical relationship rather than copied from a protected table.
• Material resistance uses visible 20°C resistivity and linear temperature-coefficient assumptions.
• Invalid negatives, invalid zero denominators, non-finite values, and power factors outside 0–1 are rejected.

Source handling

Stable scientific sources and changing publication-status sources are separate. A status watcher may update edition metadata, verification time, a source fingerprint, and a short neutral note. It may never copy protected standard prose or tables, and it may never change calculator logic.

If a status source fails or becomes stale, the site retains the last verified snapshot and replaces “current” wording with a prompt to check the official source. Core tools remain available because their math is independent of code tables.

Privacy and analytics

Calculations run locally. Optional analytics may receive only the calculator identifier, selected mode, unit-system label, and coarse interaction event. Raw voltage, current, length, wire size, load name, price, location, or custom text is never included.

Review dates

Formula pages keep their actual review date instead of receiving a new date on every build. A modified date changes only after the explanation or calculation logic changes.