Current carrying capacity

Don't know what your local regs are (which is what matters), but to get an idea, IEE regs suggest you'd need something about 650mm² c.s.a. (cable enclosed in conduit) for 1000A.

Thanks.

Hello uday pr,

Cable current capacity is dependent on cable insulation type, whether single or multi-core, plus ambient temperature.

Also de-rated further if enclosed in conduit etc.

You perhaps need 800mm₂ or 1000mm₂ size dependent on your local installation requirements.

You will find excellent sets of Cable Tables right here:

http://www.myelectrical.com/pages/cables/cableCurrents.aspx?id=061112125012

Advise here further as necessary.....

And the length of the cable run... perhaps this is the most neglected factor....in desgning cable size. 1200 amps at 50 metres length, and 1200 amps at 300 metres length......will not use the same cross sectional area cable. Good luck.

The length is @ 250 Mtr.

Thanks.

Hello again uday pr,

For any useful answer,

we need to know the following, because there are several variables:

1. Supply Voltage
2. AC or DC
3. If AC single or 3 phase
4. If 3 phase is Load across the 3 phases balanced fully
   
5. Type of cable you plan to use: PVC/Polythene/Lead sheathed/Steel wire armoured/XLPE etc
6. Cable buried direct: Advise sand/clay/soil etc - The ground material/soil will dry out over time, and the cable needs to allow for that, by being derated = A larger size than otherwise. There have been spectacular cable failures, around the World, after many years, because dry sand/clay/soil is a good thermal insulator.
   
7. Cable in Plastic Pipe (heat builds up)
   
8. Cable in Steel Conduit (Single core cable for AC must always be in the same "pipe" or magnetic induction problems occur)
   
9. Single Core/multicore (multicore for AC have reactance to consider)
   
10. Cable if in air: Local Annual Temperature Variations - Maximum/Minimum
    
11. Allowable Volt Drop at Full Current: per phase or DC = each length
    
12. There are further details required, but if you can supply the above, it should narrow down for your requirements.

Advise here please.....

Current carriying capacity depends on many factors

Allowable voltage-drop for normal operating load.
Allowable voltage-drop for future operating load as determined by motor's Service Factor.
For 1200 Amps 2Rx400sqmm aluminium is sufficient
But it depends on legth of the cable. Calculate voltage drop it must be within 2.5%
Google it you will get

I found a pretty good one at

http://circuitcalculator.com/wordpress/2007/09/20/wire-parameter-calculator/

Hi,

This is Nitin Jogi, Pleses go with maintenanceworld.com u can get lots of things there about electrical .

NITIN JOGI

nitinjogi@hotmail.com

Hello,

As per ur load u can go with 300 sq.mm cable of five numbers. and also note that this capacity is max? or any additional is there. So u can go with this it will take the sum load of 1200 amp.( if ur gounding all the cables under)

nitin jogi