Distribution Permitting Tool

What this checks

The tool gives the NESC minimum clearance for one conductor over one surface or one other line, then lists published owner requirements for the same case and flags which value controls. It covers:

• Rule 232 (Table 232-1): vertical clearance above ground, roads, rail and water
• Rule 234 (Table 234-1): clearances from buildings, signs, billboards and chimneys
• Rule 233 (Table 233-1, Rule 233B): clearance between lines on different structures

Rule 235, spacing on the same structure, is out of scope.

NESC values

Every NESC number in this tool was checked against NESC 2023 (IEEE C2-2023) using the site owner's licensed copy, and is cited by rule, table, row and column (for example "NESC 2023 Table 232-1, row 2, col D"). The NESC is copyrighted: only the individual values the tool needs are used, and no code text or tables are reproduced. Earlier public reproductions are kept as secondary sources. Badges:

• NESC 2023 verified from the owner's NESC 2023 copy
• derived computed from an owner's rule, not a published number

Values checked against NESC 2023. Confirm against your NESC edition and local requirements. The per-value source is recorded in data/nesc-clearances.js.

Over 22 kV and elevation

Rule 232C1a (vertical, Table 232-1) and Rule 234G1 (buildings, signs, Table 234-1) add 0.4 in per kV above 22 kV, phase-to-ground, to the 750 V–22 kV value. Lines over 50 kV use the maximum operating voltage. Rules 232C1b and 234G2 increase that adder by 3% per 1000 ft above 3300 ft for voltages over 50 kV; each started 1000 ft is counted (conservative).

Rule 233C2 adds the same rate for the upper conductor and for a lower conductor over 22 kV, each on its own phase-to-ground voltage (NESC 2023 reverted to this 2012 method). Rule 233B horizontal: 5.0 ft plus 0.4 in per kV over 22 kV of the voltage between conductors, the greater of the phasor difference (180° assumed, as the rule allows when unknown) or the higher circuit's phase-to-ground voltage.

Rule 234A2 / Table 234-7: horizontal building and sign clearances must also be met with the conductor displaced by a 6 lb/ft² wind (3.5 ft or 4.5 ft, plus the Rule 234G adder above 22 kV). Switching-surge alternate clearances (Rules 232D, 233B3/233C3, 234H) are not modelled.

"Over 50 kV" is taken here as a nominal phase-to-phase voltage above 50 kV. Results are rounded up to 0.1 ft.

Owner requirements

Owner values are quoted from each owner's published document: the section and quote are in the comparison table. "Controls" compares the owner value with the NESC value for the same case. Owners often measure from a different datum, such as the top of rail, the levee crown or the highest berm, so check the datum in the quote. Rows marked conditional apply only in the situation named and are left out of the "strictest" summary.

Union Pacific's value is derived, not published: the latest NESC with a 23 ft rail car, taken as the NESC value + 3 ft. Owners that publish no number are listed with a permit/contact page. The library lives in data/owners.js; see data/README.md to add owners.

Sources: NESC

Sources: owners

Location-Based Details

The Location-Based Details view takes one pole (A) or a span between two poles (A and B) and sends map queries straight from your browser to public ArcGIS REST services (no server, no keys), buffered around each pole and along the straight line between them. It measures each feature’s distance to the span and to each pole, and finds where the span crosses mapped road, rail, levee and water centerlines and polygon edges (distance from Pole A and crossing angle). Simple screening rules then flag a railroad, state highway, levee or district canal inside the buffer as a likely permit; waters, wetlands, flood zones and local rights of way are possible; 811 and pipelines are always listed. Distances are to mapped centerlines or polygon edges, not to right-of-way lines. The FAA item applies the 14 CFR 77.9(b) slopes at each pole (its own height and USGS ground elevation) to the nearest runway using the airport reference elevation. It is a screen, not the FAA’s determination. Layers that fail or are not queryable show as manual checks with the official lookup.

Each permit card also lists the required heights and placement & staking rules for that crossing, using the same engine as this view with the conductor and voltage chosen here: the NESC value, the owner values and the placement or setback rules quoted in the owner library, or “verify with owner” where the library has no value. “Design to” is the larger of the NESC and non-conditional owner minimums; owner datums (top of rail, top of bank, levee crown) differ from the NESC surface. Sources:

Disclaimer

For illustration and preliminary checks only. This is not a substitute for the governing NESC edition, the owner's current requirements and permit, or the judgment of a qualified engineer. Owner rules change: confirm the current document with the owner before design. No warranty is given.