I bet he is referencing the old concept on services. It use to be you could drop one size on the neutral SEC. I believe that was a rule of thumb but it is not accurate at all.crossman said:Are you speaking of 2008 NEC 210.19(A)(1)Excp.2 and 215.2(A)(1)Excp.2?
lmchenry said:Thanks Dennis. That is correct. Why do you think they did this? They could have gone smaller most of the time.
The use of line-to-line loads?lmchenry said:So does anyone know where the idea of one size smaller on the neutral came from?
To be honest, very few of us resi guys do calculation. I bet I have done less than 10 in the 28 years or so that I have been in business. When a house "feels" close we up it because people always seem to add on. I still generally drop the grounded conductor one size even tho I know I can go smaller.crossman said:Was a rule of thumb for those who couldn't do the Art 220 calcs?
lmchenry said:Thanks Dennis. That is correct. Why do you think they did this? They could have gone smaller most of the time.
roger said:Because they didn't read 220.61 or as Crossman says, they couldn't do the calcs.
Roger