r1 r2

[tom1]

on a loop in light circuit

is this done on switch or light fitting?

 

[Andy™]

at the furthest point in the cable, which would be at the light on the switched live

 

[tom1]

cheers andy

just r2 would be at switch then

 

[green-hornet]

r1+r2 would be at the furthest point with all two way switching closed to include the full circuit.

On a radial it is not a requirement to take a seperate reading for r2, but could be done, by the wander lead method.

At the switch you are only likely to have live, and an earth, so for all tests it may require the tests to be carried out at the light. However some testers do not require a neutral and such tests can be done at the switch.

 

[batty]

Good idea to test switch if it has a metal plate.

 

[tom1]

its for my assesment, the lights are big (5 bulbs) so its a case of taking it down to get the r1 r2 and calculating zs,

 

[Andy™]

change it for a pendant!

 

[batty]

Have you not got one of the adaptors they make life a lot easier when testing.

 

[tom1]

[quote name='Andy

 

[tom1]

Have you not got one of the adaptors they make life a lot easier when testing.

i can get one but do u still have to take it down to get to the earth,

can u use the metal fitting as the earth?? does not sound right

 

[batty]

i can get one but do u still have to take it down to get to the earth, can u use the metal fitting as the earth?? does not sound right

As long as it is not class 2 that is what you are testing.

 

[Andy™]

i can get one but do u still have to take it down to get to the earth, can u use the metal fitting as the earth?? does not sound right

if using R2 method, then yes. after all, if its a class 1 fitting, then the metal must be earthed, so by testing to that, youre proving its earthed!

 

[green-hornet]

[quote name='Andy

 

[tom1]

class 1 , so best way screw in the adaptor crock clip to light fitting itself and plug in to phase on the adaptor to get r1 r2, close switch to get reading and confim polarity,

this is same for zs but plug in the neutral as well, close switch

 

[Andy™]

if you got one of those BC adapters, there is a 50/50 chance of getting polarity wrong - just take it out and plug back in the opposite way

 

[tom1]

cheers lads

 

[Bez]

Just to tag along with this thread, when I did my testing on my extension lights it was before the fittings went up. (used conn blocks) I now have 10 GU10 spots up.

If the assesser asks me to do r1 + r2 on this circuit, will leaving the lamps in give me odd readings?

I know they will have to come out for IR tests.

Cheers

Bez

 

[green-hornet]

To be honest all types of lamps should be removed for all tests, which is why during installation tests are carried out during and final.

If you are doing a PIR then it may not be practicable to remove all lamps and this is when doing a ir test it is done with live and neutral connected and tested to earth.

You should not get any significant "odd readings" doing a r1+r2 test with lamps in situ, because the test is dead testing there should be no difference to the continuity of live or earth.