Need some help with ring final circuit please!!!

[soar]

Can somebody help me fully understand how to test a ring final circuit please!!!

 

[telectrix]

first. continuity of each of the 3 conductors end to end. if it's 2,5mm with 1.5mm cpc, then the resistance of the cpc will be approx 1.67 x that of each phase conductor. that is r1, rN, and r2.

then connect each L to the other leg's cpc at the CU. measure at each socket between L and E. the readings shoul all be the same, unless you have a spur. that is your R1+R2.

then IR at 500v

that's your dead tests. then you have the live tests, Zs, PFC.

 

[Adam W]

Check out OSG 10.3.2 (p80). There are some useful diagrams on there as well.

 

[beaver74]

first check end to end on all conductors
them take live from one leg and earth of other leg(if t+e a leg is each t+e)and connect together
then oppisite live eaths and connect together
take ohms reading from this two conections
each socket that is on the ring should have the same reading (not alway exactly)any that have wildly high readings are spurs (this is also your R1+R2 reading
do this again using live and neutral which will also prove polarity
hopr this helps

 

[mattmoo1974]

GN3 Page 33 onwards

 

[soar]

first. Continuity of each of the 3 conductors end to end. If it's 2,5mm with 1.5mm cpc, then the resistance of the cpc will be approx 1.67 x that of each phase conductor. That is r1, rn, and r2.

Then connect each l to the other leg's cpc at the cu. Measure at each socket between l and e. The readings shoul all be the same, unless you have a spur. That is your r1+r2.

Then ir at 500v

that's your dead tests. Then you have the live tests, zs, pfc.

so in step 2, it say that (r1+r2)/4 ? Is the value from step 1, end to end should divided by 4?

 

[telectrix]

yes, if you divide by 4 that will give you what to expect for R1+R2, but you still need to measure it.

 

[Sparky Ninja]

so in step 2, it say that (r1+r2)/4 ? Is the value from step 1, end to end should divided by 4?

Yes.

The value's of r1 & r2, obtained in step 1 are added together. Then divide the result by 4.
The resultant value will be the expected figure obtained on all the socket outlets incorporated within the ring final, spurs will most likely be higher.

There are other variables to consider but this is the basic principle.

 

[soar]

To do the Zs = Ze+(R1+R2),, to get the Zs is the value from step 1,end to end should be use? without dividing it by 4

 

[telectrix]

no . the end/end is r1 and r2. to calculate Zs you use R1+R2. this is the reading you get when cross linking the legs.

 

[soar]

no . the end/end is r1 and r2. to calculate Zs you use R1+R2. this is the reading you get when cross linking the legs.

so i should use the highest reading from the cross legs R1+R2