calculations

[snipes]

hello,

this is going to be one of those qestions when i hear the answer it will come back to me, but at the moment its not!

when you mesure the end the end resistance of a ring main there is a calculation to work out the length of the circuit can someone enlighten me with this formular.


thanks in advance

 

[leolec]

Is that in Table 10.1 in the 16th onsite guide?

 

[snipes]

table 9a of 17th edition osg give the resistance per meter 7.41 for 2.5 singles but i`m wanting to know the equation for calculating the lenth of the circuit , so the reading for instance is 1.62 ohms for L - L what is the length of the cable

 

[trebor]

if 1.62 is your open loop value and it is 2.5mm csa then length is

1.62 x 1000/7.41 = 218 metres approx

 

[snipes]

thats the one thank you very much

 

[ezzzekiel]

you could rearrange vd calc for length, using max vd allowed for circuit