Research — Underground · Precomputed (draft, unvalidated)
Vault sizing and cable training
A cutaway of a catalog vault, drawn in feet next to a plan at true scale: conduits enter through ports, the cable trains around the vault at its minimum bend radius, and equipment needs a clear square to work in. The sizing function and the working-clearance function do not agree, and that disagreement is the story. Pick a story, or switch to free play and read any cell of the exported grid.
Story
Free play · reads one cell of the exported grid per click
Conduits
Cable (3 per conduit)
Equipment (illustrative size)
System voltage
Vault shown · or tap one in the catalog strip below
Controls snap to the values the harness was run at; nothing between them is estimated. The sizing pick, the next size up and the three "first that" scans are read from the grid cell. Utilization is exported only for the sizing pick.
The request · what the sizing function recommends and what is drawn
Vault cutaway · isometric, feet
Plan · true scale, 1 ft grid
Harness catalog · common scale · C = working clearance, B = loop fits
Not a standard: the harness's own vault list. The outlined one is drawn above; the star marks the sizing function's pick. Dashed circle: the cable loop at its minimum radius.
Cable training · does the loop fit?
Every check at this step · the controlling row is highlighted
Source column: harness = a real harness function; demo logic = the exporter's own rule. None of these limits is a published standard here.
How the checks read it
What to know before trusting these numbers
- Draft code. 'This is a starting inventory from the 2026-07-18 extraction/audit, not a completed review -- nothing below has had human or SME-agent sign-off yet.' Standards ingestion: 'Not started'. Ported calculation services (including vault sizing): 'Not reviewed -- inherited as live production code, predates this guide's process'. Ported calculation services: not reviewed, inherited as live production code. Standards ingestion: not started.
- The vault list is the harness catalog, not a standard. A code comment calls it "ANSI standard" with no source; this page does not repeat that.
- The two functions disagree. With equipment the sizing function only widens the plan size; it ignores the equipment projection and headroom, so its pick can still fail the working-clearance function. At 34.5 kV with the 3 ft switch no catalog vault passes.
- Illustrative inputs. The splice (0.5 ft) and switch (3.0 ft) projections are the exporter's numbers; the harness has no footprint for either. The 6.5 ft headroom, the 12 x OD bend multiplier and the congestion bands have no cited source, and the NEC 110.34 label on the working-space table is a code comment that was not verified.
- Demo logic, not harness. "The loop fits" (loop diameter against the smaller plan dimension minus the equipment) and "over 100 percent" (conduits above ports) are the exporter's rules. Port positions are not exported; the port grid is a visual layout.
Every check · before, after the change, after the fix
Required values are read from the data file. The vault list is the harness catalog, not a standard. The bend and over-capacity verdicts are the exporter's own rules (demo logic); the sizing and working-clearance rows are harness functions. A row marked value is a number the function returns with no verdict.
recommend_vault_size, check_working_clearances, calculate_minimum_bending_radius, calculate_vault_conduit_utilization.Not modeled: conduit sizes, duct-bank geometry or port positions, cable racks and supports, training of more than one circuit at once, ladders and manhole necks, groundwater and structural loading, and any standards-based vault size or working-space rule. Vault wall thickness, equipment height and width, and the bundle width are drawing choices.See also:Vault sizing, hands-off walkthrough · Cable pull, vault to vault · Conduit fill