18 articles on cable sizing, voltage drop, PV/solar DC sizing, and earthing/grounding — across the Philippine Electrical Code, AS/NZS Standards, and the NEC.
Cable Sizing All Codes
A cable has to pass both an ampacity check and a voltage drop check — whichever demands the bigger conductor wins. Here is why skipping either one is a real risk.
PEC Cable Sizing
A concrete walkthrough of sizing a branch circuit cable under the Philippine Electrical Code — from design current to the final, derated recommendation.
Voltage Drop Code Comparison
All three codes care about voltage drop for the same underlying reason, but the exact limits and how they are applied are not identical. Here is the comparison.
Solar PV All Codes
A near-universal safety multiplier shows up in PV cable sizing under PEC, AS/NZS 5033, and the NEC. Here is why it exists and how it is applied.
Earthing Safety
A low earth fault loop impedance is what makes a circuit breaker actually protect you during a fault. Here is what Zs measures and why it matters.
PEC Solar Financial
System size, energy production, monthly savings, and payback period — the methodology behind the Solar System Sizing & Savings calculator, explained in full.
AS/NZS Code Comparison
Same underlying physics, different reference tables and derating conventions. A practical comparison for anyone working across both codes.
AS/NZS Solar PV
Isolator voltage rating, DC arc interruption, and IP rating are three places installers commonly get an AS/NZS 5033 solar DC installation wrong.
AS/NZS Earthing
Australia uses a Multiple Earthed Neutral system rather than a purely separate earth conductor scheme. Here is what that means for solar and general installations.
NEC Cable Sizing
The NEC’s primary ampacity table looks intimidating at first glance. Here is how to actually read it, column by column.
NEC Voltage Drop
Unlike ampacity, the NEC frames voltage drop as an informational recommendation rather than a numbered rule. Here is what that distinction means in practice.
NEC Solar PV
Article 690 governs solar PV installations under the NEC, with its own conductor sizing logic layered on top of the general ampacity tables.
NEC Grounding
Table 250.66 has separate columns for copper and aluminum service conductors — using the wrong column is a real, easy-to-make mistake.
Code Comparison All Codes
Ampacity plus voltage drop, temperature derating, grouping correction — the underlying physics is identical across all three codes. Here is what actually differs.
Earthing Code Comparison
PEC, AS/NZS, and the NEC all protect against the same fault hazard, but the terminology, systems, and sizing tables are not interchangeable.
Cable Sizing Practical
Undersized-by-eye estimates, forgotten derating, and mismatched termination ratings — the recurring mistakes that turn up in real installations.
Cable Sizing Derating
A cable’s headline ampacity rating is a best-case number. Here is what actually reduces it in a real installation, and why both corrections matter together.
Solar PV Code Comparison
One installer working projects under different codes needs one consistent mental model for PV DC cable sizing — here is that model, mapped to each code.