swa

[peteludman]

i have spent to long on my own trying to work all this out and its done my head in with different calculations for swa.

can someone help me and just give me a simple answer to how you caculate the copper equivilant of the steal wire in swa?

and another one that has confused me is k1/k2 i know this is for the different mateirals (coppper / steal eg) but do u do square route I2 t divided by that answer (k1/k2) or what.

dose this make sense or am i just making things complicated for my self.

all i want to do this for is to work out weather i need a nother earth cable in paralell to steas wire or i will just get away with the steal wire.

i have tryed working it out and ahve come up with 25mm2 two core swa the copper equivilant of the steal wire is about 6mm2 using the adiadatic equation.
and if i have a 100 a type c mcb over 0.1 s breaking and a tns supply 0.8ohms ZE i get a ZS of about 0.08 which is accetable

am i just talking rubbish

 

[ajelec10]

If you have access to it check out the nic eic technical manual its will tell you every thing you need to knoe some where there is a table that tells you what is acceptable and what is not acceptablee to be used as the cpc.

Hope this helps

AJ