cable calculation

[ample current]

When you are detremining the length of a RFC what exactly is its length, is it the total amount of cable you will use or the amount you will use divided by 2?

 

[Guest55]

Total length , ie , end to end measurment.

 

[ample current]

Total length , ie , end to end measurment.

Oh, so if its say 20m to the furthest point of the circuit, the length i use for the cable calculations is 40m.


And one more question, while im on the subject, on a lighting circuit do you include all the cable drops to all the switches or just the distance to the r1+r2 point?

 

[telectrix]

on lighting, you measure R1+R2 at the fitting across switch L and E with the switch closed. open the switch to confirm correct polarity.

cable calc. on RFC is R1+R2 = ( r1+r2)/4.

 

[Guest55]

Oh, so if its say 20m to the furthest point of the circuit, the length i use for the cable calculations is 40m.

YES


And one more question, while im on the subject, on a lighting circuit do you include all the cable drops to all the switches or just the distance to the r1+r2 point?

Ignore switch drops , just measure from consumer unit to the fitting furthest away , or as you say , the R1+R2 point

Regards.

 

[ample current]

Regards.

Thanks