Electrical / runnable MCP tool

Run the Box Fill Calculator in your AI assistant

Through the free Intry MCP server, ChatGPT, Claude, or Cursor runs this exact calculator and hands back a verdict and the cited source, not a guess. Tool name: box_fill.

What it runs: Compute junction/device box fill per NEC 314.16: conductor volume allowances, the device yoke (2×), clamps (1×), grounds (1×), and support fittings. Returns total volume used vs the box volume, pass/fail, and a suggested box if over.

Ask your assistant

Once Intry is connected, type a question like these. The assistant recognizes the job and calls the box_fill tool, then answers with the number, the verdict, and the citation.

Does a 4 inch square box hold six #12 with a receptacle and grounds?
How many #14 can I put in an 18 cubic inch box with one switch?

Inputs

FieldRequiredWhat it is
boxTypeoptionalStandard box type key (e.g. '4x1-1/2 square'), or omit and pass customVolume.
customVolumeoptionalBox volume in cubic inches (overrides boxType).
conductorsyesInsulated conductors entering the box.
deviceYokesoptionalNumber of devices (switch/receptacle yokes). Default 0.
largestDeviceConductoroptionalLargest conductor on a device. Default largest present.
internalClampsoptionalInternal cable clamps present? Default false.
largestClampConductoroptionalLargest conductor for the clamp allowance.
egcCountoptionalNumber of equipment grounds. Default 0.
largestEgcoptionalLargest EGC size.
terminalBlocksoptionalNumber of internal terminal blocks. Default 0.
luminaireStudoptionalFixture stud present? Default false.
hickeyoptionalHickey present? Default false.

Add Intry to Claude (free)

One paste and Claude can run this tool and every other Intry calculator. Free on every plan, works on your phone.

  1. Open Claude and go to Settings, then Connectors (works on the phone app too).
  2. Tap Add custom connector and paste the Intry link below.
  3. Tap Add. Done. Now just ask Claude any wire, load, conduit, or refrigerant question.
Open Claude connector setup
https://www.intrysys.com/api/mcp

Free inside Claude, on every plan (including the free one) and on your phone. No login on our end, no API key.

Using ChatGPT, Cursor, or a dev tool? See the developer setup on the main page. The endpoint is https://www.intrysys.com/api/mcp.

The tool returns its governing citation with every call (for example the NEC 2023 section or the refrigerant pressure-temperature data). Numbers are computed by the same locked engine the interactive calculator uses, golden-verified in CI and gated on every deploy.

Also on Intry