Transformer Feeder Sizes

[Alwayslearningelec]

I can't figure this out.

They want us to remove and reinstall same size xfrmr.

From the pics it does not look like two sets any where as the new feeder schedule calls for.

 

[infinity]

From the pics it does not look like two sets any where as the new feeder schedule calls for.

Did you open the disconnect switch? There could be two sets in the single FMC or the existing could be one set.

 

[Alwayslearningelec]

Did you open the disconnect switch? There could be two sets in the single FMC or the existing could be one set.

No. 8 #3/0 could fit in that conduit? Looks like 3 or 4"???? You mean one set of larger conductors?

 

[Johnhall30]

Its likely installed as a single set of #500s.

The engineer probably slapped his standard feeder chart onto the drawings and called it a day

 

[infinity]

No. 8 #3/0 could fit in that conduit? Looks like 3 or 4"???? You mean one set of larger conductors?

Yes either two sets in one raceway or one larger set. For 400 amps a single set would need to be 600 Kcmil. You can put 10-#3/0's in a 3" FMC at 40% fill. If the FMC is 24" or less you can put about 15-#3/0's. With two sets in a single raceway you need to be cognizant of derating if more than 24".

 

[augie47]

They may be replacing it with a more efficient one.
Certainly looks like a 110.16 violation on the switch.