1st let me say,,,,,,,,I'm the Black Sheep here among all you electricians seeing as how I have a tag on me called a designer,did it for a long time.I am now 74 and enjoy dropping in from time to time and seeing what you all are arguing about.:grin:
I did all of my design work in industrial plants where we worked to client general specs and they had thier minimums but in the abscense of any other direction we would always use full size neutrals,no sharing of neutrals except on 120--208 lighting,,worse case wire ampacity for conduit fill,FLA @125% on all feeders(mtrs,trans,panelboards,etc) plus derating for temp and conductor count,motor control wiring was most always #14 but oft times specs called for #12.
Instrument wire was always single pair #16 extension and multi pair#20 homeruns.
The contractors liked this hard fast rule as it was a money maker on several fronts. I noticed that there is a lot of time spent in calculating wire sizes and it appears the reason is to get the minimum wire size in place and meeting code naturally,is the smaller wire really that much of a savings to the contractor and crew labor.
dick
I did all of my design work in industrial plants where we worked to client general specs and they had thier minimums but in the abscense of any other direction we would always use full size neutrals,no sharing of neutrals except on 120--208 lighting,,worse case wire ampacity for conduit fill,FLA @125% on all feeders(mtrs,trans,panelboards,etc) plus derating for temp and conductor count,motor control wiring was most always #14 but oft times specs called for #12.
Instrument wire was always single pair #16 extension and multi pair#20 homeruns.
The contractors liked this hard fast rule as it was a money maker on several fronts. I noticed that there is a lot of time spent in calculating wire sizes and it appears the reason is to get the minimum wire size in place and meeting code naturally,is the smaller wire really that much of a savings to the contractor and crew labor.
dick
