Code Comparison Solar

Comparing DC Isolator Requirements Across PEC, AS/NZS, and NEC

DC isolation is a universal solar safety requirement, with genuinely different specific rules under each code.

DC isolation is a universal requirement for grid-connected solar under every code OhmWorks covers — the underlying safety need (a way to de-energize the DC array for maintenance or emergency) is identical. The specific requirements diverge from there.

What's Universal

• The isolator must be genuinely DC-rated, not an AC-rated device pressed into DC service
• Current and voltage ratings must exceed the array's real operating figures with an appropriate safety margin
• Weatherproofing appropriate to the installation environment

Where the Codes Diverge

Aspect	Typical divergence
Exact multiplier applied to Isc for current rating	Varies by code and specific calculation approach — see the dedicated 1.25×Isc article
Labelling requirements	AS/NZS 5033 in particular has unusually detailed, specific labelling mandates
Location and accessibility rules	Differ in specific detail even where the general principle (accessible without roof access) is shared

Check the specific isolator requirements alongside cable sizing in whichever code's PV/Solar DC Cable Sizing calculator applies to your project.

Engr. Jason Morales — Founder, SolarEnergyPH & OhmWorks

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