We noted in Part 2 of this series that if you’re working with 800A or less, you can use the next higher standard OCPD if you meet three conditions [240.4(B)]. What if you need that OCPD to be more than 800A? Any time the OCPD is rated over 800A, the ampacity of the conductors it’s protecting must be at least the rating of the OCPD [240.4(C)].
For small conductors (18AWG to 10AWG), the size and material of the conductor limit the size of the OCPD. For exa