Research — Datacenter · Precomputed (draft, unvalidated)
Service entrance: the compliance walk
A utility transformer and meter, an underground run to a building, a service panel with its working space drawn as a dashed box, and a water heater you can slide toward it. Seven checks read the same scene at once: trench cover, the service disconnect, the working space, the device interrupting rating against the available fault current, two breaker-and-conductor pairs and the grounding conductor. Pick a story, or switch to free play and move things yourself. Click a card, or a part of the drawing, to see exactly what it measures.
About this data · draft, unvalidated harness · screening illustration, not a compliance determination
- DRAFT, UNVALIDATED. ubm-agent-harness has had no human NEC subject-matter-expert sign-off (its VALIDATION.md).
- Its NEC table values come from secondary sources, not a licensed NFPA 70 copy.
- Open questions recorded there include: whether Table 310.16 is the correct 2023 citation, which 110.26(A)(1) exceptions apply (none are modeled), and whether the interrupting-rating check needs an X/R gate (it does not have one).
- This file is a screening illustration, not a compliance determination.
- SCENE: a generic three-phase 208Y/120 V building service; every dimension, the source strength (MVA, X/R), the zero path impedance, the device interrupting ratings and the obstruction position are ILLUSTRATIVE (step geometry:'illustrative').
- The available fault current is computed by circuit-calc-harness calculate_available_fault_current (three-phase bolted only).
- NEC DATA RULE: no NEC table is shipped; required values appear only as the per-case results of the functions.
File format notes (units, sentinels, grid layout, verdict mapping)
- UNITS AND SENTINELS: dimensions in inches, currents in amps (kA where named).
- In `snap`, -1 (numbers) and "" (strings) mean not set / not measured.
- GRID: top-level axes src_mva x dev_kaic (row-major, last axis fastest); cols verdict, faultKa (computed available fault current at that source strength, kA), reasonStr (string index of the harness violation, -1 if none). `tables`: workspace (condition x voltage_to_ground x depth_in), ampacity (material x size x ocpd_a), egc (material x ocpd_a x egc_size), cover (location x method x cover_in), disc_rating (category x disconnect_a), disc_count (disconnects x enclosure); each {id,title,axes,cols,cells}, same row-major rule, cols verdict + reasonStr.
- Axes may be strings.
- VERDICTS: compliant=False -> fail; a 'skipped' or 'incomplete' note -> incomplete; a rule-level 'not applicable' or 'not evaluated' note -> not_applicable (for example a grounding-conductor OCPD rating that is not one of the function's rows); otherwise pass, or tight (workspace and cover: margin under 3 in; interrupting rating: device within 10% of the available current; display bands, not rules).
- CHECKS per step, in walk order: lateral, disconnect, workspace, aic, svc_ampacity, br_ampacity, egc. `workspace` carries parts [depth,width,height] and failDims; `disconnect` carries parts (five rule groups) and failRules. `reasoning` entries are indexes into `strings`: the function's violations then notes, verbatim (aic and others may be prefixed by one composed line stating the fault-current provenance). `reqNum` is the required value as a number (-1 when none).
Reproduced verbatim from the data file's own note. Each story step and card below is tagged illustrative where its numbers are demo inputs.
Story
Free play · drag the heater, the trench handle or the device marker, or use the chips
Water heater front, from the panel face
Working-space condition (as the data names it)
Trench surface
Wiring method
Cover over the conductors
Source strength · illustrative
Device interrupting rating · illustrative
Service main device
Branch conductor material
Branch conductor size
Branch breaker
Grounding: device rating it is sized for
Grounding conductor size
Disconnect installation category
Disconnect rating
Number of disconnects
Enclosures
Every control snaps to a value the harness was run at; the page reads that cell and never estimates between two. A required value appears only where a story step has exactly the same inputs; otherwise the card says it is not exported. Width and height of the working space are not varied here.
Section through the panel wall · to scale in inches, utility side cut with a break mark
Seven checks at once · click a card to point at what it measures
No whole-service verdict is shown on purpose.
Plan · the panel room seen from above
Device board · rating, breaker, conductor, ground
How the checks read it · the harness's own text, verbatim
Every check · before, after the change, after the fix
Required values are read from the data file. Tight is a display band only (working space and cover under 3 in, interrupting rating within 10 percent of the available current), never a rule. Incomplete and not applicable are not passes. There is no whole-service verdict.
check_service_disconnect_requirements, check_panel_working_clearance, check_breaker_conductor_ampacity_match, check_equipment_grounding_conductor_size, check_equipment_interrupting_rating, check_underground_installation_cover, calculate_available_fault_current, source_impedance_from_fault_mva.Not modeled: the utility lateral (the cover check is for premises-side conductors only), clear space and storage around the panel (the heater shows only as a shortfall in clear depth), exceptions to the working-space rule (none are modeled), an X/R gate on the interrupting rating, single-line-to-ground and other fault types, load calculations, the ground-fault protection requirement (not applicable at this voltage), catalog ratings of real devices, and any real building. The drawing is schematic.See also:Service entrance, hands-off walkthrough · Breaker against conductor · Generation to rack: power path N-1