Terms of Use

01 What this service is

ieccalc.com provides engineering automation aids. Each tool takes the inputs you supply, applies a stated method, and prints the derivation: the formula, the substitution of your own numbers, the intermediate values, the clause of the standard the method comes from, and the limits of the check it performed.

The site is built that way deliberately. A tool that returned only an answer would ask you to trust it. A tool that shows its working asks you to check it — which is the only basis on which an engineer should use a computed result at all.

02 Engineering responsibility — what you must do before using a result

By using a result from this site in real work, you accept that you are the engineer responsible for it. Before you rely on any number produced here, you must:

1. Read the derivation. Every tool prints it. If a derivation is not shown for a value, do not use that value.
2. Verify the clause. Each method cites the standard, its edition and the clause, table or formula number. Check that citation against your own licensed copy of the standard, and satisfy yourself that the clause applies to your case.
3. Verify the inputs. The tool cannot know whether the figures you typed describe your installation. Ambient temperature, soil resistivity, grouping, ratings, coefficients and equipment data are yours to confirm.
4. Read the stated limits. Each tool lists what it does not check. A screening check that passes is not a design that passes.
5. Apply your own judgement and the project's requirements. National wiring rules, the employer's specification, the utility and the authority having jurisdiction may be stricter than the standard, and always take precedence.

If any of those five steps is not performed, the result must not be used. You remain the designer of record; nothing on this site transfers any part of that role to us.

03 What the tools do not do

Unless a specific tool states otherwise, the tools on this site do not:

• produce a complete design, or any deliverable that can be issued without independent engineering review;
• check compliance with any national wiring rule, local regulation, utility requirement or project specification;
• replace measurement, testing, commissioning or inspection;
• perform every check a given item of plant requires — each tool covers the checks it names, and no others;
• guarantee that the edition of a standard it cites is the edition in force where you work.

04 No warranty

The service, the calculators, the reference data and any exported document are provided “as is” and “as available”, without warranty of any kind, whether express, implied or statutory, including without limitation any implied warranty of merchantability, fitness for a particular purpose, accuracy, completeness or non-infringement.

We work to make the methods correct and traceable, and every tool ships with built-in validation cases you can open and inspect. That is evidence of care, not a warranty of correctness. We do not warrant that a calculation is free of error, that the reference data is accurate or current, or that the service will be uninterrupted.

05 Limitation of liability

To the fullest extent permitted by law, the company name that publishes this site, its owners, personnel and contributors shall not be liable for any loss or damage arising out of or in connection with the use of, or the inability to use, this service — including without limitation any direct, indirect, incidental, special, consequential or punitive loss, loss of profit, loss of contract, loss of data, cost of rework, plant damage, personal injury, or any third-party claim — whether arising in contract, tort (including negligence), breach of statutory duty or otherwise.

Where liability cannot lawfully be excluded, it is limited in aggregate to the cap stated below.

You agree to indemnify and hold us harmless against any third-party claim arising from your use of a result from this service in your own work.

06 Standards and normative references

The tools cite standards so that their methods can be checked. That policy is deliberate and strict:

• We cite by designation, edition, clause, table or formula number. We do not reproduce the normative text of a standard, and we do not reproduce its tables, figures or symbol artwork.
• Where a numerical value from a standard is unavoidable for a calculation to run, it is used as data with its source stated, so you can verify it against your own copy. It is not offered as a substitute for the standard.
• You must hold your own licensed copy of any standard you rely on. Standards are copyright works of their publishers (IEC, IEEE, ISO, national bodies and others), and nothing on this site grants you any right in them.
• IEC, IEEE, ISO, NFPA and other designations and marks belong to their respective owners. Their use here refers to the document; it is not a claim of affiliation, endorsement or certification.

If you believe any material here reproduces protected content beyond a citation, tell us and we will remove or rework it.

07 Equipment library data

The site holds a reference library of equipment — modules, inverters, transformers, cables, instrument transformers and others — which can fill a calculator's fields for you.

• Every record carries the source it came from. Some come from public regulatory lists, some from manufacturers' published data, some are generic constructions for preliminary work.
• The library is not a substitute for the manufacturer's data sheet. Before ordering or building, confirm every value against the current data sheet for the exact model, variant and rating.
• Where a record lacks a value a tool needs, the tool says so rather than filling a default silently. Do not read a field the library did not fill as data-sheet data.
• Manufacturer names, model designations and trade marks belong to their owners and appear here for identification only.

08 Reports and exported files

Exported PDF, .docx, .xlsx and JSON files are working documents. They record what the tool computed from the inputs given, and they are meant to be reviewed, marked up, checked and signed by a responsible engineer before they form part of any project record.

They are not certified calculations and they carry no professional seal. A report produced on the free plan is marked as such. Removing, altering or obscuring that marking, or presenting an export as a certified or independently verified calculation, is a breach of these terms.

09 Intellectual property

The site, its text, its calculation code, its drawings, its layout and its compiled data sets are owned by the company name that publishes this site or its licensors, except where third-party rights are noted.

You may use the tools and their outputs for your own engineering work, including work for your employer or your clients. You may not:

• copy, scrape, mirror or redistribute the site, its data sets or its code;
• resell access, or present the service as your own;
• use the content to train or evaluate a machine-learning system without written permission;
• remove attribution or plan markings from an export.

10 Accounts, plans and payment

Some tools and features need an account and a paid plan. You are responsible for the accuracy of your account details and for everything done under your account.

A licence granted by invitation, promotion or gift is subject to the same terms as a paid one, and may be withdrawn if these terms are breached.

11 Acceptable use

You must not attempt to breach or probe the security of the service, interfere with its operation, place automated load on it beyond ordinary use, misrepresent your identity, or use it for anything unlawful.

12 Forum and user content

Where the site lets you post — the forum, suggestions raised from a calculator page, corrections — the following applies:

• You keep ownership of what you post, and grant us a non-exclusive right to display, store and moderate it on the site.
• Post only what you are entitled to post. Do not post normative text from a standard, a manufacturer's confidential material, or a client's project information.
• Posts by other users are their own opinions. Posts by the IECcalc team are marked as such, and are still subject to section 2: they are technical discussion, not engineering advice for your project, and we accept no responsibility for a design based on them.
• We may edit, move, mark or remove any post, and suspend accounts, to keep the forum useful and lawful.

13 Availability and changes

We may change, add or withdraw tools, data and features, and we may change these terms. A material change will be shown on this page with a new revision date, and where you have an account we will tell you. Continuing to use the service after that is acceptance.

Methods are revised too: a tool's calculation may change when a standard is superseded or an error is corrected. Where a change affects results, the tool's validation cases and its notes are updated with it. A saved project reopened after such a change may compute differently, so re-check any result you previously relied on.

14 Personal data

Using the service involves processing some personal data — account identity, sign-in through a third-party identity provider, an e-mail address for service messages, payment records held by the payment provider, and technical logs.

15 Governing law and disputes

These terms are governed by the law of country whose law applies, and the courts of courts that hear disputes have exclusive jurisdiction — without prejudice to any right you have under the mandatory consumer law of your own country of residence.

If any provision is held unenforceable, the rest remains in force.

16 Contact

Questions about these terms, notices of a suspected calculation error, and copyright concerns: use the forum, or write to a team mailbox, not a personal address.

A suspected error in a calculation is the most useful message you can send us. Give the tool, the inputs and the result you believe is correct, and we will check it against the standard and publish the outcome.