220v single phase-480 single phase

[Todd0x1]

Ok so if 2/0 is all that is needed for the EGC then the 350-350-350-4/0 quad would work at a cost of $8300. Cost is the same for individual 350x3 + 2/0x1

 

[synchro]

Ok so if 2/0 is all that is needed for the EGC then the 350-350-350-4/0 quad would work at a cost of $8300. Cost is the same for individual 350x3 + 2/0x1

If running individual it seems like a reduced neutral could be used for the application.

 

[winnie]

2/0 is all you need for the ECG if your using 350's on a 100A breaker.

Actually, I believe that if you upsize to _two_ parallel 350's, then you need a smidge larger than 4/0 for the EGC.

#1 Al has a 75C ampacity of 100A, and a cross section of 83.7 kcmil. For a 100A circuit, #6Al is the normally required EGC.

#6 has a cross section of 26.3kcmil.

If you replace the #1Al with 2 parallel 350kcmil conductors, then you are multiplying your conductor area by 700/83.7 so you need an EGC of 220kcmil cross section.

If two parallel EGCs count for this, then parallel 2/0s are fine. But if _each_ EGC needs the full cross section (as is required in parallel conduit runs) then you need larger than 4/0.

Note: If you can push for 240/480 service, then you can run the motor (or VFD and motor) direct off 480V, and only have a small step down transformer for the 120/240V loads. Same trick if you do the step up/step down thing. No reason to step down to run a motor.

-Jon

 

[drcampbell]

Yes in my area people ... can be miles from any three phase.

Not to put too fine a point on it, but your area (44°03'25.6"N 123°06'12.2"W) seems like it's pretty far from Centerville, Pennsylvania.

What's the application? Continuous duty or intermittent? Could it be engine driven, eliminating the powerline entirely?

If it's single phase, why is four-wire cable being considered?

 

[electrofelon]

Not to put too fine a point on it, but your area (44°03'25.6"N 123°06'12.2"W) seems like it's pretty far from Centerville, Pennsylvania.

What's the application? Continuous duty or intermittent? Could it be engine driven, eliminating the powerline entirely?

If it's single phase, why is four-wire cable being considered?

I assume this would be a feeder, and he wants a neuter hence the 4 wire. As I recommend earlier, I would keep it a service and skip the EGC. If it's a feeder, could maybe skip the neuter all together and use a small 240-120/240 transformer at the load end (don't know what the 120 loads are and didn't do the math on wire vs small tranny cost, just an idea).

By the way doc, I was dead serious about going to MV. Pads have built in fusing so there is no MV equipment required. Using the MGN provision, only one CN cable required. Also one can usually get surplus pads in common voltages such as 12.47/7.2 or 13.2/7.62 for cheap on eBay. Here's a nice one:

Ermco Distribution Transformer KVA 25 120/240V Pad Mount 419 11395482 | eBay

Find many great new & used options and get the best deals for Ermco Distribution Transformer KVA 25 120/240V Pad Mount 419 11395482 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Or

25 KVA Single Phase Padmount Transformer | eBay

F. Cabinet Depth 16". M. LV Bushing Height 19". Mfg. Year 2010. LV 240 / 120BIL 30. G. Tank Depth 15". D. HV Comp Width 14". E. LV Comp Width 10". LV Bushing Height 14.

www.ebay.com

 

[tortuga]

Actually, I believe that if you upsize to _two_ parallel 350's, then you need a smidge larger than 4/0 for the EGC.

Good catch yeah 2/0 for each set.

Not to put too fine a point on it, but your area (44°03'25.6"N 123°06'12.2"W) seems like it's pretty far from Centerville, Pennsylvania.

LOL That would be quite the commute. I am not the OP thats where he is.
I lived in PA 25 years ago, and back then you could get 240/480 easily.

What's the application? Continuous duty or intermittent? Could it be engine driven, eliminating the powerline entirely?

Thats a good question, the OP stated he is using a 20HP single phase motor, so I am assuming irrigation pump.