Can someone please verify that I am doing this correctly. I am connecting 21 solar inverters to a 3 phase 4 wire 277/480 VAC panel. These inverters have a single pole 277 V output. 3 phases 7 inverters per phase 500 feet back to main service.
Assuming max/output "load" of 177 amps per phase
Here is the voltage drop formula that I am using
VD= 1.73 . 12.9 . I . L/CM
my inputs are
1. 1.73
2. 12.9 "approx" K value for copper
3. 177 amps max output I
4 500 feet distance back to service
5 CM = 300,000 300mcm
My results are this VD= 6.58 V or 2.3% vd
The engineer I am working with on this project comes out with a wire size that is 600 MCM to achieve the same VD and his methods are cryptic at least to me.
Please someone tell me that I have no idea what I am doing or confirm this is an acceptable result
thanks
Assuming max/output "load" of 177 amps per phase
Here is the voltage drop formula that I am using
VD= 1.73 . 12.9 . I . L/CM
my inputs are
1. 1.73
2. 12.9 "approx" K value for copper
3. 177 amps max output I
4 500 feet distance back to service
5 CM = 300,000 300mcm
My results are this VD= 6.58 V or 2.3% vd
The engineer I am working with on this project comes out with a wire size that is 600 MCM to achieve the same VD and his methods are cryptic at least to me.
Please someone tell me that I have no idea what I am doing or confirm this is an acceptable result
thanks