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NEC 220.5(B) Fractions of an Ampere and PV OCPD

D

DTran86

Member
Location
Houston
Occupation
PV + ESS Inspection
Hello, everyone!

I wanted to get their input on NEC 220.5(B) and if it's applicable for PV OCPD? If we have lets say 50.25A calculated with 125% included, are we safe to use a 50A OCPD? Any code references would be very much appreciated.
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
The only place I know of where the code refers to this is 220.5 and it's unclear if that can be applied to article 705. It really ought to be, be a strict reading would say it doesn't and a 50A breaker and 50A rated wiring is too small and you must upsize.

Power Control Systems could also potentially be quite useful here.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The first draft of the 2026 code adds the word "load" before calculations to make it clear the rounding only applies to load calculations.
There was a proposal to put the rounding rule in Article 110 so it would apply throughout the code, but that was rejected.
 
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