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.

Checked

Before any release, an automated check rebuilds the calculated figures from the locked engine that produces them and holds each one against the source it cites, so a number answers to its source and not merely to itself. As of the current build that suite holds 27820 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

Use it