testing

[oharaf]

HOw can you tell from testing results the difference between a radial circuit and a final ring circuit?

[EddieCurrent]

Hello,
(I'll have a go, )


r1 + r2 ,rn 'readings' are only possible on 'a1' ring main circuits ????.

Hows that for starters ?

__________________
I suppose I should add the fact that I am not a qualified electrician.

[oharaf]

cheers eddie, i'm not qualified YET either, however r1 and r2 are the readings at the socket and the cpc, I don't see how this would distinguish radial from final ring

[EddieCurrent]

Hi oharaf,

r1, r2, rn are continuity readings, ( the whole loop), Maybe you are mixing up your R1,R2 and your r1, r2's ??

__________________
I suppose I should add the fact that I am not a qualified electrician.

[oharaf]

Doh! ~Ta take your point to much reading not enough thinking thats my problem!!!

Desperately trying to finish the first 2 years of training within 6 months, so I try to complete the paper work at home and do the practical stuff at college..

[EddieCurrent]

Hi,
I'm sure you'll get there if you keep trying.
Best of luck.

[RobFurn]

Are the test results marked on a test cert? If so the test cert has a tick box to indicate its a ring.

However if you unsure the resistance reading obtained at each socket outlet of a ring circuit will be approx 1/4 of the resistance of the phase plus cpc loop resistances i.e. (r1 +r2)/4 look on page 34 of GN3 for more details

[oharaf]

Thanks Rob, the readings aren't on a cert it is an exercise i've to do for college.

The question is;

"Is there any way we can tell from the results recorded, whether a socket oulet is part of the ring final circuit or a spur from the ring?"

Can you help on this one?

Cheers

[comms]

cross connect legs of ring at cu (p/n). now test between p/n at each socket reading should be the same or within 0.05 ohm at each socket (this will be 1/2 the r1 or r2 loop reading) any large rise in reading will be a good indication that the socket will probably be a spur from final ring.

Then do the same with p/e to get your R1+R2.

[oharaf]

That is great comms, I was only doing the cross cenection test last week, but it was only on a ring with no spur.

Would this apply even if the spur was a fused spur?

[RobFurn]

Same for fused spur but of course you cant plug your socket tester in a fused spur so you will have to take the cover off.
The reading is higher as you are distrupting the measurement of the ring by measuring from a spur off the ring

[oharaf]

Thanks for your help, AGAIN!