Design check
PASS means the numerical check meets the entered criterion. It does not certify standards compliance or approve a cable for installation.
| Check | Status | Basis |
|---|
Calculation trace
| Quantity | Value |
|---|
Correction factors
| Factor | Value |
|---|
Outstanding engineering review
Recorded design inputs
| Input / assumption | Recorded value |
|---|
Method and scope
Balanced three-phase model. Ib = P/(√3 V PF), S/(√3 V) or entered current. Corrected capacity = table rating × parallel sets × product of correction factors. ΔU = coefficient × I × one-way length / (1000 × parallel sets). Fault current in kA = fault MVA × 1000/(√3 V). Thermal withstand in kA = k × area × parallel sets/(1000 √t). Limits, data sources and assumptions are recorded above. Equal current sharing is required for parallel sets. See the calculator’s method panel for exclusions.
Reference data and method
Embedded cable table for your selection
Equations, scope and source differences
This conversion retains the workbook’s balanced three-phase load, correction-factor, voltage-drop and adiabatic conductor checks. kW means electrical input power; use rated current or convert shaft output using efficiency first.
- Ib = kW × 1000 / (√3 × V × PF), or kVA × 1000 / (√3 × V), or an entered current.
- Iz = tabulated ampacity × parallel sets × total correction factor. Utilisation = 100 × Ib / Iz.
- Workbook impedance mode: ΔU = √3 × Z × I × L / (1000 × N). This is a screening approximation without separate R/X and starting PF.
- Manual R/X mode: coefficient = √3 × (R cos φ + X sin φ), with R/X in Ω/km at the stated conductor temperature. Running and starting PF are separate; lagging loads only.
- Manual mV/A/m mode: ΔU = coefficient × I × L / (1000 × N). Enter separate running and starting coefficients appropriate to the three-phase circuit.
- Upstream voltage-drop percentages are added to cable-only percentages. Zero means an explicit zero-contribution assumption; confirm the complete route/network.
- Isc (kA) = fault MVA × 1000 / (√3 × V). It (kA) = k × S × N / (1000 × √t). k units are A·√s/mm². This tool restricts the constant-current model to 0.1–5 s. Device let-through I²t, screen/armour duty and minimum fault/disconnection checks need separate assessment.
Formula cross-checks: Schneider Electric Electrical Installation Guide — voltage drop; cable short-circuit withstand. These references do not verify the embedded workbook tables.
Changes made during conversion
- Missing lookups block calculation; they never silently become a correction factor of 1. Burial-depth lookups require exact supported values.
- Unsupported core arrangements, MV aluminium impedance, non-11 kV MV reference use and XLPE copper duct ratings require manual data. PILC 70 mm² reference impedance is blocked because of its anomalous trend.
- Buried PVC requires manual factors instead of borrowing XLPE soil factors. XLPE copper offers the workbook’s 70°C and 90°C rating columns; the supplied 90°C temperature factors cannot automatically derate a 70°C rating.
- Grouping arrangement is explicit. Duct grouping factors use duct columns. Parallel sets must be included in the grouping count.
- The LV aluminium mV/A/m values are used directly rather than divided by a rounded 1.732 and multiplied back. This removes a small workbook rounding difference.
- Starting acceptance uses a separate entered criterion. Conflicting workbook text about 1.5 times running limits and misleading cached summaries is not copied.
- PILC k selection now follows its named family (the workbook’s four-character comparison did not match “PIL”). All default k values still require temperature/material verification.
This is a screening and documentation tool, not an automatic cable selector. It excludes single-phase/DC, unbalanced/harmonic and neutral heating, detailed VSD models, cyclic ratings, soil drying, full network motor starting, protection grading, fault-loop disconnection, PE sizing, cost optimisation and final regulatory approval.
Design workflow and workbook case studies
Define load and source data → establish installation conditions → select a candidate cable → calculate all four checks → resolve failures and unknowns → record evidence in the ten-point review → print for independent checking.
The case register is retained for reference. Missing case inputs are not invented or treated as passing designs.
Source register and offline access
The workbook includes differing course-scope statements. This tool exposes LV and MV as reference screening, with manual data required where the embedded information is inadequate. Verify applicable licensed standards, editions and manufacturer data before design issue.
The hosted calculator and download are restricted by the portal access policy. A downloaded HTML is self-contained and works without login; access revocation cannot disable copies already downloaded. Project data is not transmitted by the calculator. Hosting authentication and access logs are separate.
Save inputs as JSON to continue later. Print to PDF or export CSV for records. The offline HTML download contains the tool and reference tables, not your current project inputs. External reference links need an internet connection.