Electrical / runnable MCP tool

Run the Voltage Drop Calculator in your AI assistant

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

Add it to your assistant Open the interactive calculator

What it runs: Compute voltage drop for a copper or aluminum branch/feeder run using the NEC K-factor method (VD = 2·K·I·L / CM, K=12.9 Cu / 21.2 Al). SCOPE, and it governs how you read the answer: the 3% voltage-drop target is an Informational Note under NEC 210.19, and NEC 90.5(C) states that informational notes 'are informational only and are not enforceable as requirements'. Conductor AMPACITY (NEC 310.16 + 240.4), by contrast, is mandatory under 210.19(A), which requires an ampacity 'not less than the larger of' the load-based minimums. So this tool returns THREE sizes and they are not interchangeable: the voltage-drop-only minimum (a recommendation), the ampacity minimum at standard conditions (a requirement), and the minimum overall, which is the LARGER of the two per 210.19(A). If the wireSize you pass cannot carry the amps you pass, the verdict reads 'Undersized for the load' and a BLOCKER names 210.19(A) - the voltage-drop percentage is still computed and still correct, and it is still not permission to pull that conductor.

Ask your assistant

The one rule that makes it reliable: name Intry in your question. That is what tells Claude to run the voltage_drop tool and answer with the real number, the verdict, and the citation. Leave Intry out and Claude may just guess from memory, which is exactly what you are trying to avoid. Type something like:

“Use Intry to check the voltage drop on a 120 ft run of #10 copper at 20 A, 240 V.”

“Ask Intry if #12 is too small for a 15 A load 90 ft away, and what size keeps me under 3%.”

Inputs

Field	Required	What it is
wireSize	yes	Conductor size, AWG or kcmil (e.g. '12', '1/0', '250').
amps	yes	Load current in amps.
length	yes	One-way run length in feet.
voltage	optional	System voltage (default 240).
phase	optional	single or three phase (default single).
material	optional	cu = copper, al = aluminum (default cu).

Add Intry to Claude

One paste and Claude can run this tool and every other Intry calculator, right from your phone.

Add Intry to ClaudeOpens Claude with Intry already filled in.

Claude opens with the Intry connector already filled in. Review it and click Add.
(If a field is blank, paste the link below into the URL field.)
In any chat, tap + then Connectors and switch Intry on. Then name Intry in your question (“use Intry to…”) so Claude runs the tool instead of guessing.

https://www.intrysys.com/api/mcp

No login, no API key, and it works on every Claude plan, right from your phone.

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

Every answer comes with the cited NEC section, so you can check it or show an inspector. The numbers come from the same calculator we run on intrysys.com, and we re-check every one automatically before anything goes live, so the number Claude hands you matches the code.

Also on Intry

Voltage Drop Calculator (interactive)

The same engine as a hands-on calculator, with the full readout, chart, and worked examples.

All runnable tools

The full Intry MCP server: every calculator your assistant can run, and how to connect.