Conductory sizing

[Marc M]

Hey Jerry,
I have a (green) chart that lists the correct sizing for conductors to disconnects, The question is; how come this (green) chart is so popular in the HI industry and it is based primarily on two conductor types? Isnt this misleading to the inspector as the inspector must determine the conductor type first to discern whether or not the make up is correct, rather than relying on this chart that only has 2 types?

[Jerry Peck - Codeman]

That chart was an attempt to reduce a more complicated table into a simpler table, and combine it with a simple table, Table 310.15(B)(6), for service entrance conductor sizes (albeit that Table 310.15(B)(6) is not always applicable to dwelling unit service entrance conductor sizes).

The green table you posted also has errors in it, so in trying simplify the information down, the information has now become incorrect in various areas.

I give them credit for trying to simply the information, however, I give that attempt to simplify the information a failing grade as it contains incorrect information.

Sometimes, and that green table is an good example of this, one can simplify the information too much and it then becomes incorrect - which is what happened with that effort producing the green table. It really should have been 'unsimplified' a little, which would have made it simplified and correct, instead of simplified and incorrect.