Insulation resistance low voltage lighting

[iwire4]

I have recently qualified and am coming towards testing a re-wire. I have fitted 30 low voltage downlighters with transformers. Apart from removing the bulbs do I need to do anything else before pumping 500volts through the circuits. ie will 500volts damage the transformers or are they removed from the circuit before this test, or done at 250volts? This has not been properly explained to me.
Any advice greatfully received.
Thanks.

 

[Johnny-G]

You should've IR'd the circuit before fitting the transformers and you're going to have to remove or isolate them now to get a L/N reading.
You can test the individual units with L&N combined to E once they're removed if you like.

 

[mayfair]

Agree with johnny-g much easier to do before fitting any lamps transformers, thermostats, etc you can see how to do the 250v test on youtube The learning lounge videos will help. I feel your tutors should have run through this along with live and dead testing and the order in which you do it, with you

Forgot to say dont forget the Electric shower and Hob very sensitive components . The tests are known as tests 1 and 2 if it helps you looking.

 

[iwire4]

Guys, thanks for the advice. Makes sense and I could have saved myself some work if I had asked the question before. A lesson learnt not to be forgotten. I need some lessons in using this forum as well. Apologies for the late reply.
Cheers.