Zs on lights spur of ring

[rick]

At a property today I found that several lights have been taken as a spur of a ring main. At the end of the spur I get 1.33 Zs which is too high as it's on a 32A B MCB and should be lower than 1.16.

If I convert this to a fused 3A spur with FCU, can I used the 3A fuse to calculate the max Zs allowed? (which would be OK if so)

 

[Sintra]

Yes that would be ok.

 

[flukey]

your Zs would be for the circuit from the fcu to last light and if a 3amp fuse is ok load wise then thats what you should use

 

[rick]

Thanks guys, that's what I will do.

 

[keniff]

max would be about 16ohms you could go up to 13 amps if you needed as the max on that is about 2ohms