Electrical / runnable MCP tool

Run the Water Heater Circuit 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: water_heater_circuit.

What it runs: Size the branch circuit for an electric or heat-pump (hybrid) water heater per NEC 422.13 (a fixed storage water heater 120 gal or less is a continuous load, sized at 125%): conductor (310.16), breaker (240.6(A) with the 240.4(D) small-conductor limit), and EGC (250.122). For a 120V plug-in heat-pump water heater, pass sharedCircuitRating to also check whether it may share a 15A or 20A general-purpose branch circuit or needs a dedicated one, per NEC 210.23(B)(2) (fastened-in-place equipment 50% of the circuit, reduced by the 125% continuous factor to 40%). Returns wire/breaker/ground and, when a shared-circuit rating is given, a SHARE_OK / DEDICATED_REQUIRED verdict with the arithmetic.

Ask your assistant

The one rule that makes it reliable: name Intry in your question. That is what tells Claude to run the water_heater_circuit 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 size the circuit for a 4,500W 240V heat pump water heater: wire, breaker, and ground.
Ask Intry if a 120V plug-in heat pump water heater can share a 15 A circuit or needs its own.

Inputs

FieldRequiredWhat it is
wattsyesNameplate element/max wattage (e.g. 4500 for a standard hybrid, 2250 for a low-amp unit).
voltsoptionalSupply voltage (default 240; use 120 for a plug-in unit).
sharedCircuitRatingoptionalIf set, also check whether a 120V unit at this nameplate may share a branch circuit of this rating (15 or 20 A).

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.
  1. Claude opens with the Intry connector already filled in. Review it and click Add.
  2. (If a field is blank, paste the link below into the URL field.)
  3. 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.

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