Intry Verified receipt

Is the Intry Three-Phase Motor Calculator accurate and NEC compliant?

The provenance receipt for the Intry Three-Phase Motor 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.

Short answer: It computes from the NEC sections named below (NEC 2023), and our automated checks hold its answers against values written from those sources for the cases the checks cover, not for every input you can enter. Whether an installation is NEC compliant is decided by the inspector, not by a calculator. Your AHJ has final say. The table current sizes the branch circuit; your motor's nameplate sizes the running overload device (430.32), which this tool does not size. Wound-rotor and DC motors take a different percentage from Table 430.52(C)(1) and are out of scope; so is a three-phase synchronous motor, whose current is in Table 430.250's own synchronous columns, and a motor in other than continuous duty (430.22(E)). Every figure an Intry calculator computes comes from a locked source module, not hand-typed. 35,006 automated checks, one suite for the whole site rather than a per-tool count, re-derive the numbers before each deploy from the tables this site holds, read from the cited NEC Table 430.250 and 430.248 full-load currents and the Article 430 branch-circuit rules. This is our own deterministic gate, not a third-party audit. The per-tool receipt is public at https://www.intrysys.com/verified.

The receipt

Calculated from

NEC 2023 Table 430.250, Full-Load Current, Three-Phase AC Motors · NEC 2023 Table 430.248, Full-Load Currents, Single-Phase AC Motors · NEC 2023 430.6(A)(1), which current to use · NEC 2023 430.22, Table 310.16 and 110.14(C)(1)(a), the conductor · NEC 2023 430.52(C)(1) with Table 430.52(C)(1), and 240.6(A) standard ratings · NEC 2023 240.4(B), 240.4(D) and 250.122(B), the ordinary-circuit rules this page compares against · NEC 2023 240.4(G) and Table 240.4(G), why a motor branch circuit may sit under a larger breaker (NEC 2023). Reused word for word 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

What it reads

NEC 2023 Table 430.250, Full-Load Current, Three-Phase AC Motors
NEC 2023 Table 430.248, Full-Load Currents, Single-Phase AC Motors
NEC 2023 430.6(A)(1), which current to use
NEC 2023 430.22, Table 310.16 and 110.14(C)(1)(a), the conductor
NEC 2023 430.52(C)(1) with Table 430.52(C)(1), and 240.6(A) standard ratings
NEC 2023 240.4(B), 240.4(D) and 250.122(B), the ordinary-circuit rules this page compares against
NEC 2023 240.4(G) and Table 240.4(G), why a motor branch circuit may sit under a larger breaker

Checked

Checked on every build, most recently on November 11, 2026. On every build, an automated check runs the locked engine that produces these figures and holds its answers against the values this site holds, 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 35,006 checks, and this page has to clear them too. This is our own deterministic gate, not a third-party audit.

Tested safeguards

The maximum breaker sizes it gives, the conductors it hands to the conduit fill calculator, and the full-load current, conductor and maximum breaker its Check your working problems show, carry their own safeguards: when the code behind them is broken on purpose, the safeguards catch it.

Source changes

No source has been added to or removed from this tool since this record began on October 24, 2026.

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. The table current sizes the branch circuit; your motor's nameplate sizes the running overload device (430.32), which this tool does not size. Wound-rotor and DC motors take a different percentage from Table 430.52(C)(1) and are out of scope; so is a three-phase synchronous motor, whose current is in Table 430.250's own synchronous columns, and a motor in other than continuous duty (430.22(E)).

Frequently Asked Questions

Is the Intry Three-Phase Motor Calculator accurate and NEC compliant?

It computes from the NEC sections named below (NEC 2023), and our automated checks hold its answers against values written from those sources for the cases the checks cover, not for every input you can enter. Whether an installation is NEC compliant is decided by the inspector, not by a calculator. Your AHJ has final say. The table current sizes the branch circuit; your motor's nameplate sizes the running overload device (430.32), which this tool does not size. Wound-rotor and DC motors take a different percentage from Table 430.52(C)(1) and are out of scope; so is a three-phase synchronous motor, whose current is in Table 430.250's own synchronous columns, and a motor in other than continuous duty (430.22(E)). Every figure an Intry calculator computes comes from a locked source module, not hand-typed. 35,006 automated checks, one suite for the whole site rather than a per-tool count, re-derive the numbers before each deploy from the tables this site holds, read from the cited NEC Table 430.250 and 430.248 full-load currents and the Article 430 branch-circuit rules. This is our own deterministic gate, not a third-party audit. The per-tool receipt is public at https://www.intrysys.com/verified.

Use it

Open the Three-Phase Motor Calculator The full Intry Verified standard