About IECCalc
IECCalc is a set of electrical power engineering calculators that follow IEC and IEEE standards and say which clause each number comes from. It is built by a practising electrical engineer for the work he does himself: cable sizing, fault levels, protection checks, earthing, transformers and solar plant design.
What the site is
Every calculator on IECCalc takes engineering inputs, applies the method of a published standard and prints the derivation next to the result — the formula, the substitution and the clause reference. Nothing is a black box: if a number came from a table, the table is named; if it came from a formula, the formula is shown with its inputs.
The calculations run in your browser. No project data is sent anywhere to be calculated, and the free tier performs the complete calculation rather than a teaser of it. What the paid tier adds is the paperwork around the calculation: reports, saved projects, equipment libraries, batch runs and exports.
There are 14 calculators today, across cables, short circuit, protection, transformers, motors, earthing, lightning, solar PV and site design conditions.
Which standards the calculations follow
Each tool names its own basis. Across the site the calculations follow:
IECCalc reproduces the methods of these standards. It does not reproduce their text: a standard is a copyrighted document and has to be bought from IEC or IEEE. Where a tool needs a tabulated value, the value is stated with the table it belongs to, so the number can be checked against your own copy.
How the engines are checked
A calculation engine that only agrees with itself proves nothing. Every engine here is run against values that were published by somebody else — a worked example in the standard, an annex table, or a reference case — and the comparison is built into the tool as a panel you can open and run yourself.
At the last check that came to 142 individual comparisons across 10 calculators, with none failing: the earthing grid against the IEEE 80 Annex B example, the low-voltage short circuit against the worked 400 V example of IEC TR 60909-4 clause 3, cable sizing against IEC 60364-5-52 Annex E.52.2, motor efficiency against IEC 60034-30-1 Tables 5 and 7, lightning risk against the IEC 62305-2 Annex E cases.
What the tools do not do
- They do not replace the engineer. A result is an input to a design decision, not the decision.
- They are not certified or approved by IEC, IEEE or any other body, and no such claim is made anywhere on this site.
- They do not invent equipment data. Where a calculation needs a manufacturer figure — a breaking capacity, a cable's zero-sequence ratio, a machine's locked-rotor ratio — the tool asks for it and says that it is asking for datasheet data.
- They do not silently substitute a simplified method for the one the standard specifies. If a case is outside the scope of the implemented method, the tool says so instead of returning a number that looks right.
The full legal position is in the terms of use, section 2.
Corrections
If a number here disagrees with your calculation, that is worth reporting: several tools carry corrections that came from readers. The forum has a branch per calculator, and each tool's page carries a direct contact line.