Inspecting and test query

[ample current]

Im just doing some home work and running through the test procedure, ( i have my elecsa assesment week after next ) and reading gn3 and onsite guide, when it says test every point on the lighting cicuit does that mean every light AND switch when testing for r1 + r2

I am thinking testing only at the light with the switch on and testing between the returning conducter from the switch and the CPC,(thus checking continuity) but the cpc at the switch will be a slightly higher reading and the conductor is a lil longer and the highest reading from the entire circuit noted on the SoTR

I think the switch for the landing 2 way in the hall will be the furthest point of the circuit for the cpc but not the returning strapper as that will be back at the light or am i just confusing myself a bit.

Thanks

 

[telectrix]

the furthest point on a lighting circuit is always on the switch live at the last light and cpc. if lights are wired loop in at light, the cpc to the switch may make a small difference, but i wouldn't worry. it's generally at the lights that you take readings. just be sure of your terminology. it's R1+R2 ( caps). r1 and r2 are end/end readings on a RFC. if you take reading at switches, OK, the cpc will be longer, but the L will be shorter. kind of cancel out.

 

[ample current]

OK Thanks
so R1 is for lighting circuit, or is this any radial circuit?
r1 for ring final circuit.

 

[telectrix]

R1, R2 (caps) refer to the resistance of the conductors the CU end to the end of a radial or the mid-point of a ring.

r1,r2,( small letters) refer to the end/end resistance of a conductor of a ring. as a ring is effectively 2 cables in parallel. then R1+ R2 = (r1+r2)/4. divide by 2 as conductors are in parallel, and divide by 2 again as the csa is double.

 

[markthespark]

I am also trying to brush up on my testing skills and i am unsure about the R1+R2 test on a lighting circuit.

When testing for R1+R2 and Continuity is it acceptable to go round to every switch and test between L + CPC and record the highest reading or has this got to be done at the light fittings aswell?

And when carrying out insulation resistance on a circuit with LV downlights is it acceptable to do a LN to CPC test?

Many Thanks

 

[telectrix]

1.best done at light fittings with switches on.

2. either disconnect trannies and test, or do as you say. note on cert. that it's L&N/E. a full test would include testing across primary and secondary sides of the trannies.

 

[markthespark]

Thanks again Tel.

 

[Deleted member 26818]

Conduct the test as Tel says at the fitting, operate the switch to prove polarity.
Same as with a Zs test.
Remember, that parallel paths must be disconnected when conducting the R1+R2 test.