Rojo-sy (Redsy):
To me, the 4/0cu THHN looks good, for Parallel runs in the same Raceway.
That being said, I have a few things to mention:
1: Be sure to discuss the Parallel Service Feeders idea with the Utility Service Planner, which is involved with this Project.
This needs to be verified per their compiance before installed - because even if the Building Department accepts it per the EE's drawings, the Utility may not approve it.
To verify compliance, try:
- Contact the Service Planner for the district / area of the project.
If unknown, call the Utility and begin the "Hunt" until you find someone with information, who is familiar with your project. - Verify minimum compliance via "ESR" documents (Electrical Service Requirements).
Most Utilities have their ESR manuals + UGS (Underground Structures) manuals available for download via their websites.
Typically these texts are saved as .PDFs
Be double sure and verbally verify what the ESR allows, with a Service Planner - then procede with the installation. - Contact the Utility Service Inspector whom will be reviewing the installation and approving it, and eventually submitting release for Meter.
After verification of Parallel Service Feeders is obtained, then contact the EE and have that person revise the Single Line, to reflect the proposed Service Feeders + 4" Duct(s).
Lastly, re-submit the revised Planset to the Plans Examination department (Plan Check).
A Bit Of FYIOut here - in Southern California, Service Feeders are
"NORMALLY" installed by the Utility - and we install the Ducts + Pull Ropes.
With a new Pad Mount Transformer installation, we would install Ducts + Pull Ropes for both the Primary side Feeder, and the Secondary side Feeders - along with the Vault and Service Equipment.
A few Utilities - City of Anaheim being one of them, requires the EC to install Service Feeders (Secondary side only), plus terminate them in the Service Equipment.
All proposed Service Designs are per the governing Utility's ESR / UGS manuals, with verifications from the Service Planner - prior to submitting to the building department's plan check.
Typical Duct sizes are 4" Minimum, with 5" ducts sometimes quoted.
Most designs will be minimum of Two 4" ducts for a 400 amp Service.
A typical Service / Utility design for me involves at least Six (6) 4" PVC Ducts, Concrete-Encased; and One (1) 4" PVC Duct - also Concrete-Encased, for the Primary Feeder.
When doing any Service installs in Anaheim, the use of Aluminum makes things much nicer -as opposed to Copper Feeders.
With 12 Parallel Runs, using 750 AL is SOOOOOOO much easier to feed and manipulate, compared to 500 Copper!!!.
Just goes to show the differences each of us face in our trade, per which Ocean you are closest to!
One last thing:
I "Ass-U-Me" you are planning to derate the size of the Grounded Neutral Conductor for this feeder?
Be sure to verify this is OK with BOTH of the AHJs - the Utility Department + the Building Department.
Ohh, one more "Last Thing":
If the 3 Phase load is "minimal", as compared to the L-N 1 Phase load, and therefore the "High Leg" is also being derated in size, verify this with the AHJs too.
Find out if they (the Utility) wants the "High Leg" to be in Position "C" (ØC) at the Meter, or if they do not care anymore.
I am kind of curious what Utilities still want Hot/Cold Sequencing, or still use single stator watt-hour meters on 240/120V 3Ø 4 Wire Delta Services.
Make sure to place that High Leg in Position "B" on the Load side of the Service disconnect + identify it "Orange" - wherever the Grounded Neutral Conductor is also present.
Good luck and have fun!!!
Scott
