Practical

Building a Personal Cable Sizing Checklist You Actually Use

A practical, adoptable checklist framework that consolidates the recurring lessons from across this entire article series.

This series has covered a lot of individual lessons — here's a consolidated, practical checklist pulling the recurring themes together into something you can actually keep and use.

Before Calculating

• Confirm the correct governing code for this specific project
• Confirm the correct code edition currently adopted by the AHJ
• Identify the real design current — correctly, including whether the load is continuous
• Establish the real installation method and real ambient conditions, not generic assumptions

During Calculation

• Run ampacity and voltage drop as two genuinely independent checks
• Apply temperature and grouping derating explicitly, not selectively
• For solar DC circuits, apply the correct safety multiplier to Isc, and recalculate combined current at every combining point
• Size the earth/ground conductor from the applicable table — never estimate it

Before Ordering Materials

• Round up, never down, if the exact calculated size isn't available
• Confirm the protective device is correctly coordinated with the final cable size

Before Submitting Documentation

• Show the supporting calculation, not just the final size
• Confirm consistency across every project document

Run every project through the applicable OhmWorks calculators as the backbone of this checklist.

Engr. Jason Morales — Founder, SolarEnergyPH & OhmWorks

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