Partial testing and R1+R2.........

[magnoliafan89]

So when doing partial testing, when doing ring circuits i have a query.

Do end to end prove each conductor is a ring. In the area on the test sheet it says r1+r2 OR r2. Is it ok to do end to end and fill in the cpc end to end reading (r2) into this box and do zs of every socket to not only get a zs reading but also prove continuity as the tester alerts to mixed polarity.

 

[telectrix]

youse confused r1, r2,rN are end to end. R1+R2 or R2 are different.e.g. R2 will be using a wander lead to each point, recording the highest. for a ring generally, R1+R2 = (r1+r2/4)

 

[magnoliafan89]

After i posted this i realised my error

 

[telectrix]

After i posted this i realised my error

20 minutes in the naughty corner.

 

[Zdb]

I suppose you could do end to end of CPC (r2) and then divide by four to get R2?

 

[Strima]

Why would you only do partial testing? If the circuit is locked off then I would do the full lot of dead tests.

Measuring CPC end to end and dividing by four will not confirm earthing connection at each point or polarity.

 

[Deleted member 9648]

Why would you only do partial testing? If the circuit is locked off then I would do the full lot of dead tests.

Measuring CPC end to end and dividing by four will not confirm earthing connection at each point or polarity.

Partial testing would not be acceptable for initial verification, but is acceptable on an EICR. For example if a measured Zs reading is comparable to the measured Zs recorded on the original EIC then it would be reasonable to assume the R1+R2 will also be comparable, and so not carry out that test.
So that's why you might only do partial testing.
​

 

[Strima]

Partial testing would not be acceptable for initial verification, but is acceptable on an EICR. For example if a measured Zs reading is comparable to the measured Zs recorded on the original EIC then it would be reasonable to assume the R1+R2 will also be comparable, and so not carry out that test.
So that's why you might only do partial testing.
​

I agree but on a ring final how would you confirm polarity at each point and identify any crossovers without fully dead testing?

 

[magnoliafan89]

My company is a social landlord. We do partial testing if we have existing certificates of an installation.

I confirm polarity of each socket on a ring by doing a zs reading at each socket. Any polarity issues my tester wouldnt start the reading and beep at me the issue. So by doing end to end then zs at each point i confirm its a complete ring amd each point is correct polarity wise

 

[Zdb]

Obviously full testing is better on a RFC but if you really must do partial testing on a RFC I would obtain the R1+R2 by doing the end to ends, adding them together then dividing by four, as said above. Just an R2 value on a RFC doesn't quite seem right.

 

[Deleted member 26818]

Do you do any IR testing?

 

[magnoliafan89]

I dont just do an r2 reading. I do end to end to confirm the ring then do zs at each one
Stupidly i was thinking that where it says r1 r2 or r2 i could jusy put the cpc end to end in...but after i posted i realised this result was the r2 from say using the wandering lead.

In regards to the IR i do if i need to do a full test or the circuits are not on the rcd side.

 

[Deleted member 9648]

I agree but on a ring final how would you confirm polarity at each point and identify any crossovers without fully dead testing?

As above Zs testing will confirm polarity. Full dead testing on a RFC is very time consuming and disruptive if the layout of the circuit is unknown. R1+R2 readings will be skewed by spurs, and identifying spurs from spurs will involve considerable dismantling.....I use my judgement to decide whether a RFC has issues that need further investigating or commenting on after end to end, IR and Zs tests.
None of the above applies to initial verification in which the layout of the RFC should be known and full testing must be carried out.

 

[DPG]

[QUOTE="magnoliafan89, post: 1506944, member: 98919
In regards to the IR i do if i need to do a full test or the circuits are not on the rcd side.[/QUOTE]

No IR testing at all on any RCD protected circuits?

 

[magnoliafan89]

[QUOTE="magnoliafan89, post: 1506944, member: 98919
In regards to the IR i do if i need to do a full test or the circuits are not on the rcd side.

No IR testing at all on any RCD protected circuits?[/QUOTE]
No unless the tenant has commented on tripping