Short-Circuit Withstand Constants — Memorise These | Mshezi

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Stop Guessing Cable Sizes — Learn the Exact Method Practising Engineers Use on Real Projects

Module 1: Cable Sizing Fundamentals — Standards, Principles, and the Design Process

Foundations of Cable Sizing
Module 1 Learning Outcomes
Why Cable Sizing Matters
The 4 Critical Parameters
LV vs MV — Voltage Levels in Practice
Copper vs Aluminium — Choosing the Right Conductor
Cable Insulation Types
The Standards Behind the Calculator
Reading the Calculator — Colour Coding System
Short-Circuit Withstand Constants — Memorise These
Your Calculator — 6 Sheets, One Workflow
Module 1 Complete

Module 2: SANS 10142 and IEC 60364 — What Every Engineer Must Know

Inside the Excel Calculator
Module 2 Learning Outcomes
The Calculator: 8 Sections — A Through H
Project Information
Load Data — The Inputs That Drive Everything
IFL and Istart — The Two Currents
Cable Type Selection
Derating Factors
Cable Selection — Choose Size
Voltage Drop Check
Short-Circuit / Fault Current Check
Results Summary — The Traffic-Light View
The Pre-Loaded FAIL Scenario — Why It Fails
The PRINT REPORT — Your Professional Deliverable
Module 2 Formula Reference Card
Module 2 Complete

Module 3: Current-Carrying Capacity — Tables, Grouping, and Installation Methods

Step-by-Step Cable Sizing Workflow
LEARNING OUTCOMES
The 8-Step Cable Sizing Workflow
Define Load Requirements
Steps 2 & 3 — Set the Limits, Choose the Cable
STEP 4 — Determine Derating Factors
STEP 5 — Select Cable Size from Tables
Steps 6 & 7 — Voltage Drop & Short-Circuit Checks
STEP 8 — Compliance Review & Iteration
WORKED EXAMPLE — 75 kW Motor Cable
Engineering Judgement & Documentation
Module 3 Summary
What's Next in the Masterclass

Module 4: Derating Factors — Ambient Temperature, Grouping, Thermal Insulation

Where Most Engineers Make Costly Mistakes
Module 4 Learning Outcomes
Why Voltage Drop Matters — The Real-World Consequences
THE FORMULA DISSECTED
SANS 10142-1 — Voltage Drop Limits (Clause 5.3)
THE FAIL SCENARIO
Sensitivity Analysis — What Changes VD and By How Much?
Upsize the Cable
Solution 2: Add Parallel Cables (N > 1)
Reduce the Cable Run — And the Three-Solution Comparison
Starting Voltage Drop — The WARNING You Must Understand
Verify the Calculator — Do the Maths by Hand
The 6 Most Common Voltage Drop Mistakes
QUICK ESTIMATION TOOL
Real-World Scenarios — Where VD Failures Hurt Most
Module 4 Complete

Module 5: Voltage Drop Calculations — Method, Formula, and Acceptable Limits

Short-Circuit & Thermal Withstand
What You Will Be Able to Do
What Happens to a Cable During a Fault?
PROSPECTIVE FAULT CURRENT
WORKED EXAMPLE
The K-Factor — What It Represents
THERMAL WITHSTAND FORMULA
WORKED EXAMPLE
Effect of Clearing Time on Cable Withstand
Using the Calculator: Section G Fault Current Check
MV CABLE TABLES
Three Mistakes That Cause FAIL Results
What To Do Now — Hands-On Practice
MODULE 5 SUMMARY

Module 6: Motor Cable Sizing — Starting Current, Protection, and Coordination

Installation Methods & Derating
What You'll Learn in Module 6
Why Cables Are Derated
The Six Derating Factors
Solar Radiation — South African Context
Cable Grouping — The Hidden Derating
Combining Factors: F_total and Ir
Calculator Section D — Derating Inputs
LV Derating Quick Reference
Practical Exercise — Your Turn
Module 6 — Key Takeaways & Assessment
Module 6 Complete

Module 7: Professional Cable Schedules and Documentation

Real-World Case Studies
Module Purpose
Learning Outcomes
The 5 Case Studies at a Glance
Case Study 1 — Industrial Motor
Case Study 2 — Mining Long Run
Case Study 3 — MV Substation Feeder
Case Study 4 — Petrochemical Harsh Environment
Case Study 5 — Aluminium Cable Sizing
Calculator Focus — Which Check Controls the Cable?
Practical Engineering Activities
Resources & Downloadable Tools
MODULE 7 — KEY TAKEAWAYS

Module 8: Worked Examples — 4 Complete Projects from Load List to Final Schedule

Common Mistakes & Design Pitfalls
Module Purpose
Learning Outcomes
The 8 Mistakes at a Glance
Mistake 1 — Ignoring Derating Factors
Mistake 2 — Wrong K-Factor for SC Withstand
Mistake 3 — Misreading Starting VD WARNING as a FAIL
Mistakes 4 & 5 — Over-Design vs Under-Design
Mistakes 6, 7 & 8 — Three Quick But Costly Errors
Calculator Focus — Reading Section H Correctly
Deep Dive — K-Factor Error Impact on SC Withstand
10-Point Design Review Checklist
MODULE 8 — KEY TAKEAWAYS

MODULE 9: From Calculation to Design Documentation

From Calculation to Design Documentation
What This Module Is About
Learning Outcomes
The 6 Sections of a Cable Sizing Report
PRINT REPORT Sheet Walkthrough
The SANS Compliance Statement
Revision Control for Engineering Calculations
Engineering Justification Statements
Registered Engineer Sign-Off
Transmittal & Submission Process
Document Control — File Naming & Version History
Case Study: Mining Calculation Package
Key Takeaways — Module 9
MODULE 9 COMPLETE

MODULE 10: Optimising Cost, Quick Estimation & Red Flags

Optimising Cost, Quick Estimation & Red Flags
Learning Outcomes
Cable Cost Optimisation
Copper vs Aluminium — When Does Al Make Sense?
Parallel Cable Economics
Rules of Thumb for Early Project Stages
MV Cable Optimisation
Cable Sizing Red Flags — Know When to Stop and Review
AI & Automation in Cable Sizing
Optimisation in Action — Calculator Exercise
Key Takeaways
What's Next — Capstone Project

MODULE 11: Full Industrial Panel Cable Sizing Exercise

Full Industrial Panel Cable Sizing Exercise
What This Module Is — and Is Not
The Scenario: Highveld Mining Support Facility
Every Cable Gets Three Checks
Cable 01: 75 kW VSD Motor
Cable 01: Key Calculations Walkthrough
Cable 02: 22 kW DOL Motor — Buried Direct
Cable 03: 15 kW Lighting Feeder — Conduit/Duct
Cable 04: 100 kVA Sub-Feeder — 3 Cables Grouped
Derating Factors: Quick Reference for This Project
Assembling Your Calculation Package
How Your Capstone Will Be Reviewed
Five Common Capstone Mistakes
Indicative Results — Use to Check Your Work
You've Completed the Capstone Project

COURSE DOWNLOADS

01_10-Point_Design_Review_Checklist
02_Quick_Estimation_Tool_Max_Cable_Run
03_The_6_Most_Common_Voltage_Drop_Mistakes
100kW_525V_VSD Start_Failed Scenario_Module 4
100MVA_525V_Module 5
Case Study 1_Module 7
Case Study 2_Module 7
Case Study 3_Module 7
Case Study 4_Module 7
Case Study 5_Module 7

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Short-Circuit Withstand Constants — Memorise These

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