confused on testing

[new boy21]

Hi Lads doing an insulation resistance test and getting a reading of 324.5 ohms on a ring main does anything below 500 ohms need to be rewired?

Thanks

 

[Sintra]

When doing an IR test the scale should be in Meg ohms not ohms.
Are you using the correct instruement for the test.

 

[Johno]

I have had it before where one of the sockets was the problem, sounds like some fault finding is needed (whoopee). Assuming you are testing it right and everything is definately unplugged/disconnected, but it doesn't mean rewiring it anyway, maybe just a section of it

 

[new boy21]

Thanks for your reply what reading justifies a rewire then? Would this be under 100?

 

[Sintra]

Circuits up to 500V must have a minimum insulation resistance of 1.0 Meg ohms when tested at 500v dc with all current using equipment disconnected. 612.3.2

 

[Johno]

if it is under 1 M ohm then it needs sorting but not neccessarily rewiring, you need to trace it.

 

[Adam W]

It's not quite as simple as "<1M Ohm = Rewire" - there are other factors which need to be taken into consideration which could be causing the low reading, such as equipment (eg surge protector, heater, tv signal booster, anything with a neon on it) plugged in or connected, or even just a poor termination.

It's worth doing some further investigation such as hunting around for hidden equipment (try the loft),and/or splitting the ring and testing each leg, before you go diving in and rewiring the whole property - that kind of behaviour can earn you an undesirable reputation.

 

[acat]

It's not quite as simple as "<1M Ohm = Rewire" - there are other factors which need to be taken into consideration which could be causing the low reading, such as equipment (eg surge protector, heater, tv signal booster, anything with a neon on it) plugged in or connected, or even just a poor termination.

It's worth doing some further investigation such as hunting around for hidden equipment (try the loft),and/or splitting the ring and testing each leg, before you go diving in and rewiring the whole property - that kind of behaviour can earn you an undesirable reputation.

How very very true


Chris

 

[Phil]

i used to work with a guy that could tell by just looking at the board with the cover still on whether it needed re wiring or not. what a clever guy, made me wonder why i had spent good money on a tester with qualities like that he always seemed to get the full rewire after as well maybe it was due to his shock tactics with what might happen to the wiring etc without a new board and re wire.

 

[Jason Smith]

question posed to the OP needs to be answered by him- was your reading in M ohms, i.e. million ohms or in Ohms ? - extremly important m8 !

 

[new boy21]

Thanks guys. This house is a void and has no one living in it. Doing the test on my multi meter at 500 volt and its in meg ohms,just don't feel very confident and don't want to bull**** anyone just an honest report

 

[Jason Smith]

m8- megger testers read up to 299 mo, my 1652b to 500 mo. (500,000,000 ) ohms. your reading at that level is very good. 1mo is the basic pass !! but i would recommend investigation at that level !!

 

[UNG]

i used to work with a guy that could tell by just looking at the board with the cover still on whether it needed re wiring or not. what a clever guy, made me wonder why i had spent good money on a tester with qualities like that he always seemed to get the full rewire after as well maybe it was due to his shock tactics with what might happen to the wiring etc without a new board and re wire.

Has he appeared on rogue traders or has nobody caught up with him

 

[Graeme Harrold]

Have you tried testing with L&N together with respect to the CPC? This would rule out neons and PIR's (if they aint blown!!)