Standards & References

OhmNexus calculators are grounded in widely recognized electrical engineering standards and conventions. This page summarizes the main references our tools draw on and how to apply their results responsibly.

Standards and conventions we reference

123 standards from 16 standards bodies are referenced across 51 pages. Every figure resolves to SI units and the fundamental power relationships; where a tool also accepts a customary unit such as AWG, kcmil, CCA or horsepower, it names the unit and the conversion it applies. The clause or table that governs a particular result is cited on the tool that applies it, not here.

United States

• NFPA, National Fire Protection Association. the National Electrical Code (NFPA 70), which leads every US installation, ampacity and sizing question on this site. Cited on 24 pages: NFPA 70, NEC 220.5(A), NEC 110.14(C), NEC 210.19(A), NEC 210.20(A), and 36 more.
• IEEE, Institute of Electrical and Electronics Engineers. power measurement, stationary battery sizing, and portable-cell practice. Cited on 32 pages: IEEE 1625, IEEE 1725, IEEE Std 1459, IEEE 1184, IEEE 485, and 6 more.
• UL, UL Solutions. safety certification for batteries, energy storage and transformers. Cited on 6 pages: UL 1973, UL 9540, UL 5085.
• NEMA, National Electrical Manufacturers Association. motor and transformer nameplate conventions. Cited on 7 pages: NEMA MG 1, NEMA ST-1.
• ANSI, American National Standards Institute. US nominal system voltages and their tolerance ranges. Cited on 4 pages: ANSI C84.1.
• SAE, SAE International. automotive battery ratings and the J-series EV charging couplers used well beyond the US. Cited on 6 pages: SAE J537, SAE J1772, SAE J3400, SAE J541.
• IES, Illuminating Engineering Society. illuminance targets and photometric method for the lighting tools. Cited on 2 pages: IES LM-79, IES LM-80, IES TM-21, IES/ALA RP-11.
• ASTM, ASTM International. material and test methods referenced in the guides. Cited on 1 page: ASTM E283.

International

• IEC, International Electrotechnical Commission. installation practice, standard voltages, and the battery safety series the battery tools rest on. Cited on 35 pages: IEC 62619, IEC 62133-2, IEC 61960, IEC 60364, IEC 62133, and 27 more.
• ISO, International Organization for Standardization. generator set ratings and duty classes. Cited on 6 pages: ISO 8528.

Europe and the UK

• BSI, British Standards Institution. UK wiring regulations (BS 7671) and emergency lighting. Cited on 13 pages: BS 7671, BS 5266-1.
• EN, European Standards (CENELEC). the European battery and UPS series. Cited on 10 pages: EN 50342-1, EN 62619, EN 50272-2, EN 50549, EN 61427-2, and 3 more.
• DIN, Deutsches Institut für Normung. the German cranking-current basis. Cited on 2 pages: DIN 43539.

Asia-Pacific

• AS/NZS, Standards Australia and Standards New Zealand. Australian and New Zealand wiring rules, cable selection and battery installations. Cited on 14 pages: AS/NZS 3000, AS/NZS 5139, AS/NZS 3008, AS/NZS 3008.1, AS/NZS 4086, and 1 more.
• JIS, Japanese Industrial Standards. the Japanese battery ratings used across Asian vehicle fitments. Cited on 6 pages: JIS D 5301, JIS C 8714, JIS C 8712, JIS C 8715.

Canada

• CSA, CSA Group. the Canadian Electrical Code (CSA C22.1). Cited on 12 pages: CSA C22.1, CSA C22.2.

How we apply them

Our AC-mains conversion tools lead with US nominal voltages (120/240 V) in their examples and input hints, and accept any system voltage, including 230/400 V; battery and DC nominal voltages (12/24/48 V) are universal. Where a result depends on a convention, such as single-phase versus three-phase, power factor, system voltage, or temperature, the calculator exposes that choice as an input and states the assumption. The formula and a worked example appear on every tool, so you can trace exactly how a result is produced.

You can see these conventions at work across the site. Our power conversion calculators convert between amps, watts, volts, kVA and kW for DC, single-phase and three-phase systems, and our battery calculators work in amp-hours and watt-hours. Where a definition varies, such as which horsepower a motor rating refers to, the tool that uses it states the value on its own page. Browse the full library in the calculators directory.

Use results responsibly

Our calculators are educational and planning aids. Real-world electrical work is governed by local codes, site conditions, and manufacturer specifications that a general-purpose tool cannot capture. Always verify critical results against the applicable code, and for any installation or safety-critical decision, consult a licensed electrician or professional engineer.