I have a service where I'm installing a 240V/200amp single phase distribution panel 400 feet away from the main service. My total demand load is 141 amps and is 95% 240 volt heat trace circuits. I sized the service for 160 amps with no more than 3% voltage drop on each circuit. When I sized this I came up with 2 parallel #4/0 conductors. Can I run this in one 3" conduit instead of using two parallel runs of conduits?
Voltage Drop calculations
Length FT
Amps
Wire Size
Circ Mils
Voltage Drop
% Vd
Double Throw Disconnect to DP#1
400
160
#4/0 X 2
423200
3.901701323
1.625709
This is for when DP1 is 400 feet or less from the double throw disconnect
DP#1 to HT Power Kits (case #1)
100
13.4
#10
10380
3.330635838
1.387765
7.232337161
3.013474
Total
This is for Circuits from DP#1 less that 100Ft to HT Power Kit
Voltage Drop calculations
Double Throw Disconnect to DP#1
400
160
#4/0 X 2
423200
3.901701323
1.625709
This is for when DP1 is 400 feet or less from the double throw disconnect
DP#1 to HT Power Kits (case #2)
275
13.4
#6
28240
3.366607649
1.402753
7.268308972
3.028462
Total
This is for Circuits from DP#1 from 160 FT to 275 FT to HT Power Kit
Voltage Drop calculations
Double Throw Disconnect to DP#1
400
160
#4/0 X 2
423200
3.901701323
1.625709
This is for when DP1 is 400 feet or less from the double throw disconnect
DP#1 to HT Power Kits (case #3)
400
13.4
#4
41740
3.313080977
1.38045
7.214782301
3.006159
Total
This is for Circuits from DP#1 from 275 FT to 400 FT to HT Power Kit
Note: for 4/0 Parallel feeder in one 3" conduit
195 amp X 2 = 390
De-rate for 6 current carrying conductors 80% = 312 amps