Originally Posted by Trumpy
Originally Posted by gfretwell
. I had to use the optional calculation to get in under 200a when I put on my addition.
Greg,
Is that like the diversity (demand at any point in time) calculations that we use here to size mains conductors?
It is the idea that not everything is all turned on at the same time, is what I'm trying to say.

Yes, NFPA has 2 different was to compute diversity in the load calcs. Basically the primary method deals with each load separately and the optional method applies the diversity to the total computed load. It is a little more complex than that but that is the basic idea. I think NFPA errs on the safe side anyway. I doubt I ever even see 60% of capacity with the spa running. I have looked with my clamp and it usually runs well below that. According to FPL (the PoCo) my average usage is about 14a on a 200a service. I understand there are peaks and valleys in there and we really care about maximum instantaneous draw. One of the cool things about the smart meter is they can give you statistics hourly, daily or monthly.

Greg Fretwell