Cable sizing

[wilmer197]

Wondered if anyone can help ? If i was running in a sub-main for an extra c.u how would i calculate the size of cable. Foe example if my new c.u was going to supply 2x32a 3x6a circuits what calculation would i use to find the size of cable. read through the regs and i cant get my head round it.

Many thanx people

If i were to use a 16mm t+e which carries a maximum of 57A would this be sufficient ? Even though the total of the amps the mcb's could carry would be 76A that you dont add them up like this.

 

[Darkwood]

It all depends on the loading of the circuits and if you can apply diversity to the individual circuits once you've got a ball park figure for the loading then pick an appropriate cable to carry the load not forgetting because the earth is serving mulitple circuits it needs to match the phase conductor for size.
Your query does not give enough info as to what each circuit is doing or the expected loading of these circuits.
More info please.

 

[Guest123]

Hi.

You would have to carry out a maximum demand calculation, allowing for diversity.

 

[patchman21]

You will also need to know the length of run, installation method, type of cable etc before you can calc it.

 

[Mac]

Wondered if anyone can help ? If i was running in a sub-main for an extra c.u how would i calculate the size of cable. Foe example if my new c.u was going to supply 2x32a 3x6a circuits what calculation would i use to find the size of cable. read through the regs and i cant get my head round it.

Many thanx people

If i were to use a 16mm t+e which carries a maximum of 57A would this be sufficient ? Even though the total of the amps the mcb's could carry would be 76A that you dont add them up like this.

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