400amp 3 phase 4 wire cable sizing help.

[Sintra]

So for the 30m run on ladder rack from the 400 amp switchfuse the 400amp isolator which has to be mutlicore aomoured i was calculating 185mm .

i believe i will have trouble terminating this into those outlets.. Might need to use those special crimp packs which turn and reduce to get the cores in.

There's always the option of using 2 smaller csa multicore cables in parallel. If you do your calcs for this method. It can sometimes work out less and be easier to terminate etc.

 

[Fred Faulkner]

yes, but is the design load 400A or considerably less? it might just be that a 250A supply is insufficient and they've gone for the next standard size up.

Ofcourse this is why i queried it originally but as i have had no real answers back other than just price for the above 250kva supply which is worst case senario not the loading which may be considerably less.

 

[Fred Faulkner]

There's always the option of using 2 smaller csa multicore cables in parallel. If you do your calcs for this method. It can sometimes work out less and be easier to terminate etc.

Ive looked at this metod and ive calculated 2x 50mm 4 core swa to achieve the 360amps ruffly does that sound right mate?

 

[Leesparkykent]

[h=3]Multicore 90°C Armoured Thermosetting Insulated Cables[/h]Tables Apply to: H6942XL, H6943XL, H6944XL, H6945XL, Tuff Sheath,
Voltage:400V
Load:199.53kW / 360A
Length:30m
Method of Installation:In free air or on a perforated cable tray
Cable Size:150mm²

 

[telectrix]

i estimate 2 x 50mm will give you 326A method E. ( table 4D4A).

have you looked up xlpe? that will give you more as it's rated to 90deg.C, but the problem is that the switchgear you're connected to is probably only 70deg.C.

 

[Sintra]

Ive looked at this metod and ive calculated 2x 50mm 4 core swa to achieve the 360amps ruffly does that sound right mate?

Where are you getting the 360A from I thought it was 400.

 

[Fred Faulkner]

Where are you getting the 360A from I thought it was 400.

250kva converter to amps is 360amps ruffly

 

[Fred Faulkner]

i estimate 2 x 50mm will give you 326A method E. ( table 4D4A).

have you looked up xlpe? that will give you more as it's rated to 90deg.C, but the problem is that the switchgear you're connected to is probably only 70deg.C.

The terminations you got any advice ive terminated a few 95mm 3 cores but never a 150/185mm or parraelling 2x cables

i will look up xlpe now thanks.

 

[davesparks]

The terminations you got any advice ive terminated a few 95mm 3 cores but never a 150/185mm or parraelling 2x cables

i will look up xlpe now thanks.

Advice, get the right spreader box and you'll be fine

 

[Sintra]

250kva converter to amps is 360amps ruffly

But the current rating of your cable needs to be greater than the protective device as it won't be connected to a fixed load.

 

[Fred Faulkner]

Advice, get the right spreader box and you'll be fine

Thanks dave