IR test method 2

[james king]

is this test exepatble and does it bypass tranny and bulbs ect? i have been told on here befor ye so i am just wondering

 

[james king]

lol

so how could u get a reading of 0.00Mohms on a lighting cct using method 2?????

 

[mayfair]

M8 should you be doing these tests .............or are you just asking questions, its just you should really know the answers to some of these basic questions, we all have to learn but be careful.......please

so using method 2 wouldnt by pas surge protectors? were would u usally find these?

 

[telectrix]

short circuit, N/E reversal at a JB or fitting,

 

[james king]

im at collage we had this convo yesterday at work with boss. but i still didnt understand.. but if short cct then surly it would trip ???

 

[james king]

so how can u get a reading of 0.0Mohms if the rcd does not trip? surly an N-E reverse at a jb would cause RCD to trip

 

[telectrix]

but you never mentioned rcd in your op.

 

[james king]

I was must wondering about the method 2! So why would that matter about an rcd

 

[pushrod]

If you ever get a reading of 0.0 MΩ on an insulation resistance test you could still have a resistance of up to 50,000Ω, which is being rounded down to zero by the meter. The next thing to do is a continuity test to confirm if it is a dead short.

 

[SimpleSimon]

But in your scenario why would you be testing?
You could have been called to a customers house to say there lighting circuit has tripped the MCB. You come to test insulation resistance and than.........

 

[james king]

Sorry simon I have no clue on what u r talking about? Mcb tripping??

 

[TPES]

suppose you had a load of high bay lights 25 ft. up in the air. would the client pay for the hire of a cherry picker and the time to remove the loads for you to test?

What if you had fitted these as a new job, just installed high up on a factory, each unit connected on the circuit, how would you do your IR tests?

 

[malcolmsanford]

If it was a new circuit then I would have done the IR on it before fitting the luminares or connection into the DB.

 

[TPES]

If it was a new circuit then I would have done the IR on it before fitting the luminares or connection into the DB.

Ok. So you'd be testing just one long length of cable before you' of even put any switches on or fittings up? Would you be testing the length of cable for your feed then test again the s/l cable for your lighting? I'm not disagreeing with anything, just interested in others methods

 

[malcolmsanford]

What are you supposed to be testing on your IR .................just a piece of cable, the IR test is not for accessories or luminaires.

I would run the cables, in your conduit or trunking, or whatever your erection method is, do your switch drops and then before I started to fit the luminaires I would do a full IR test on the cable i've installed, and that would mean activating the switches to include the drops. If your switch incorporated a neon, then I would just choc block out the cables and not fit the switch.

This would for me confirm that the cable I've installed is not damaged. Once I fitted all the accessories and luminaries I would do a L/N to E IR test on 250 volt DC just to confirm that i hadn't nipped a cable when fitting the fixtures.

 

[mayfair]

If you read the thread from the begining you will see the point that is trying to be made m8

If it was a new circuit then I would have done the IR on it before fitting the luminares or connection into the DB.