On Fri, 10 Nov 2017 18:07:00 -0600, Robert Nichols wrote:

On 11/10/2017 03:22 PM, Jim Wilkins wrote:
"rangerssuck" wrote in message
...

from 8KV to 13KV (half the I^^2R loss).

Ours is "19.9KV" which may be a regulatory step, otherwise why not
call it 20KV?.

Probably the same reason that telephone central offices run on 48V DC, nominal, to stay within the "Less than 50V" section of the electrical codes. (Actual voltage is somewhat above that except when actually running on battery power.)

19.9 KV is 34.5 KV / sqrt(3), ie, the distribution-system
primary voltage of 19.9 KV looks like a 3-phase phase-voltage
from 34.5 KV transmission-line-voltage.

--
jiw