What makes you question things?

[IAmSparkytus!]

@ToonSparky is correct to terminate into the board before testing, at least for the CPCs anyway. If you're not connecting the CPCs to the earthing arrangement, then your IR testing is non compliant:

643.3.1 The insulation resistance shall be measured between live conductors and between live conductors and the protective conductor connected to the earthing arrangement

GN3 (17th ed, am3) tells me that this requirement came in in 2008, prior to this you could just test to the CPC without it terminated. Old habits die hard huh?

Maybe this is why I was taught to do it this way back when I was an apprentice.

So it could be worthwhile carrying out all R1+R2 and end to end tests while disconnected from the board but IR tests onwards cables should be terminated?

 

[Pretty Mouth]

Reading that 643.3.1, the wording of "live" conductors suggests live, as in energised.
IR is a dead test.

From definitions:

Live conductor (see Live part).

Live part. A conductor or conductive part intended to be energized in normal use, including a neutral conductor but, by convention, not a PEN conductor.

 

[Pretty Mouth]

Maybe this is why I was taught to do it this way back when I was an apprentice.

So it could be worthwhile carrying out all R1+R2 and end to end tests while disconnected from the board but IR tests onwards cables should be terminated?

Sure, no reason I can think of why you shouldn't do it that way. Much easier to find which conductor belongs to which leg of a ring final for the fig.of 8 tests if you do it before the cables are terminated

 

[LewisM]

When somewhere has been 'tested' very recently and all the switches and sockets etc are still painted/caulked to the wall with 30 years worth on them?

 

[GBDamo]

Posted in error

 

[ipf]

So does taping your ring legs together.

Sounds like you're brasting.....?....or something?

 

[telectrix]

Sounds like you're brasting.....?....or something?

or he's into bondage. as for questioning, every day i question my sanity. but if i can do that, it's proof that I'm not crazy, so still working. Catch 22.

 

[mattg4321]

I test rings before connecting anything. I test IR on each circuit as I go. Connect cpc. Then IR test. Then connect line and neutral.

 

[Dustydazzler]

Am I being completely thick , but why? do you need to connect the earths to the earth bar to conduct your initial IR tests

at college we did dead tests prior to connecting circuits to the board

 

[loz2754]

Maybe this is why I was taught to do it this way back when I was an apprentice.

So it could be worthwhile carrying out all R1+R2 and end to end tests while disconnected from the board but IR tests onwards cables should be terminated?

This is what I do

 

[SparkySy]

@Dustydazzler
This is done so that any cable that may have become damaged during installation is tested to earth as well. That way you can be sure there is definitely no faults through say the building steel ect that would have been missed by doing the test disconnected from the earth bar. If that makes sense

 

[GBDamo]

Am I being completely thick , but why? do you need to connect the earths to the earth bar to conduct your initial IR tests

at college we did dead tests prior to connecting circuits to the board

@Dustydazzler
This is done so that any cable that may have become damaged during installation is tested to earth as well. That way you can be sure there is definitely no faults through say the building steel ect that would have been missed by doing the test disconnected from the earth bar. If that makes sense

Although there is nothing to stop you IR testing circuit lives to incoming CPC, or MET if local, as well as circuit CPC to tick that box.

IR becomes a five point test (obviously not TPN) instead of three but the ease of access and not having to redress the CU makes it worth it.