Intry Verified receipt

Is the Intry Transformer OCPD Calculator accurate and NEC compliant?

The provenance receipt for the Intry Transformer OCPD Calculator: the exact authority its values derive from, the edition they are keyed to, who has final say, and what our automated checks hold them against, rebuilt from their cited source.

The receipt

Calculated from

NEC 2023 450.3(B) and Table 450.3(B), with Notes 1, 2 and 3 · NEC 2023 240.6(A) and Table 240.6(A), standard ampere ratings · NEC 2023 240.4(F) and 240.21(C)(1), primary-only protection (NEC 2023). Reused verbatim from the locked engine, never re-written for this page. The documents it rests on are listed in the source receipt on the tool page.

Edition

NEC 2023

Checked

Before any release, an automated check runs the locked engine that produces these figures and holds its answers against values written from the source it cites, so a checked number answers to its source and not merely to itself. The check covers the cases someone wrote a check for, not every input the tool accepts: it tells you where a number comes from, and it is not a proof of every value. As of the current build that suite holds 31163 checks, and this page has to clear them too. This is our own deterministic gate, not a third-party audit.

Runnable

A reference engine behind the published numbers on this site. Runnable access is offered on the calculators exposed at the Intry MCP endpoint.

Final say

Your AHJ has final say. Table 450.3(B) gives maximums, so a smaller device is usually permitted and often required by the load, the conductors or the transformer inrush.

Frequently Asked Questions

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