4000 amp 480v 3ph switch gear

[electrofelon]

35 years
all heavy commercial/industrial
oil/gas
defense infrastructure
bio/pharma
manufacturing
mining
IBEW member for my first 4 years
most of it field work and design build

As I have proven even the example used in this thread would have been easier using the conventional method
2 less conduit
2 less gounds
6 less conductors
16 less terminations
2 less pulls
absolutely no disadvantage vs isophase, in fact a better more cost effective method

I didnt mean any disrespect, many engineers havent done much hands on. I just was wondering if you have done an installation with 4,5, or 6 conductors in parallel and played the "make it look nice without cutting any off game..." and I was proposing that you may feel differently after trying it.

 

[armrey]

4000A Service

4000A Service

How do you account for using 90C amperage wire rating with 75C equipment lugs?

 

[kwired]

How do you account for using 90C amperage wire rating with 75C equipment lugs?

Nearly all general use conductors used today have 90C insulation on them, nearly all terminals they land on are only rated 60C or 75C. You have to go with the lowest rating of what is connected for minimum allowed size of conductor, but can still use 90C ampacity as a starting point when ampacity adjustments are required - primarily adjustments for number of current carrying conductors in a raceway, or ampacity adjustments for ambient temperature.

 

[Smart $]

How do you account for using 90C amperage wire rating with 75C equipment lugs?

Though Code references are a bit dated, read the following...

http://www2.schneider-electric.com/...7/en_US/Wire Terminations 0110DB9901R2-02.pdf

Any questions?

 

[octavian]

I need help on determing what size wire and how many per phase for 4000 amp run of 480v 3ph between a tranformer and switch gear. I know that 500 is 380. if I multiply that by 10 it is 3800 and by 11 it is 4180. Would that be 10 or 11 sets? And is a set defined as A,B,C,& GRD?

A little late to the game but noticed you didn't mention a neutral. If wired in a delta config no neutral used but should include it anyway for future use. If transformer is POCO equipment connecting a service a ground is not normally run nor wanted.