Tabulated current carrying capacity

[schoe]

Hi all can some one help me out with this,

It = In divided ccxcixcgxca

I have a 32 amp mcb divided by cc 1 x cg 0.80 x ca 1.03 = 38.8 amps current carrying capacity.

What would the tabulated current carrying capacity be, as it should be higher than the current carrying capacity.

Hope that's not to confusing,

Thanks chris

 

[johnboy6083]

For a ring you work out Ib and multiply this by 1.67 to get your protective device. This is In. You then find It, by dividing Ib by the derating factors (Cg, Ci, Cg, Ca and finally 0.725 if a 3036 fuse).You then have a provisional conductor size. Check this with the following, max mv/a/m = max vd/ (length x Ib). You look down the tables and find a conductor with a mv/a/m figure less than this. You then need to check thermal withstand and disconnection times. You also need to select or calculate a CPC.

 

[i=p/u]

so say 26A for standard A1 ring circuit x by 1.67=44A protective device 45A . so then 26A/0.725x0.9= 40A so say clipped direct t&e would equal 6mm for (It) for volt drop you 7.3x 26 x100m/1000/4= 5V as vd... but this is 6mm (It)

 

[Rampage]

You can only use a 30 or 32A protective device on a ring final, minimum CSA is 2.5 unless it's MICC when it's 1.5.
Reg: 433.1.103 green or 433.1.5 red.

 

[i=p/u]

cheers , im chasing stars with this....