Research — Building Electrical · Early Access

Thirteen NEC checks for the meter-to-building slice, each with its citation.

A package of deterministic check functions. Each takes installation facts the caller states and returns pass/fail with the violations, notes and the NEC (2023) citation. It covers the service point outward: panels, overcurrent protection, branch circuits and devices, and deliberately leaves out load calculation such as NEC Article 220.

NEC

Interactive demos

Breaker vs conductor →Pick conductor size, material and terminal class, slide the breaker through standard ratings, and see the NEC 240.4(D)/(B), 240.6(A) and Table 310.16 verdict. Draft, unvalidated.Auto ▶

Harnesses in action

Scripted chat-and-viewer examples where this domain's harness is one of the tools. Illustrative, not live sessions.

Grid to rack: one design, six harnesses →Illustrative, scriptedA grid-fed datacenter reviewed stage by stage: transmission tap line, substation bus scheme and fence, duct bank, hall power path, service-gear fault current against its interrupting rating, and liquid cooling. Each stage hands a result to the next.

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What it can do

check_breaker_conductor_ampacity_match
Breaker rating against conductor size under NEC 240.4/240.6 and Table 310.16, copper and aluminum.
check_panel_working_clearance
Working-space depth, width and height against NEC 110.26(A).
check_service_disconnect_requirements
Service disconnect count and minimum rating (NEC 230.71, 230.79).
check_equipment_grounding_conductor_size
Equipment grounding conductor size by overcurrent device rating (NEC 250.122).
check_equipment_interrupting_rating
Equipment interrupting rating against available fault current (NEC 110.9).
check_underground_installation_cover
Minimum burial cover against NEC Table 300.5(A).
nec_propose_fix
For a failing check, the smallest change that passes the same check when re-run: the next conductor or grounding-conductor size, a clearance, a burial depth, a support spacing, or a required device. Applicability facts (dwelling or not, location, voltage) are never changed. A rating limit is returned as a minimum to meet, not a product.

A worked case

Input

14 AWG copper conductor on a 20 A breaker, 75 °C terminals.

Result

Not compliant: 15 A maximum, per NEC 240.4(D). That is the fixed small-conductor cap, which the next-size-up allowance cannot raise. A 15 A breaker passes.

Where this stands

Draft, unvalidated. No licensed electrician, electrical PE or inspector has reviewed any of the 13 functions, and output should not be represented as authoritative NEC guidance until a review is logged. Some table values rest on secondary sources rather than a licensed NFPA 70 copy.

Open questions

Whether Table 310.16 is the right 2023 citation, and whether single-source copper ampacity values match an authoritative copy.
Whether the 110.26(A)(1) exceptions should be modeled.
Whether the interrupting-rating comparison needs an X/R-ratio gate.

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