Bit confused here, IR testing.

[Thommo]

Hi all, this is probably a daft question to most of you.
At training centre I have started dead testing. When I get to the 3 point IR test on a single circuit should I switch off the breaker for that circuit .Hopefully I am correct in removing any lamps on a lighting circuit and turned switches on with all points closed. On a radial or final ring I have closed all points turned sockets on.
I think the procedure may be different when doing a global test, not sure.
Just a bit confused about the circuit breaker as I know it is switched on for continuity of cpc test.
Thanks in advance for any input

 

[telectrix]

Hi all, this is probably a daft question to most of you.
At training centre I have started dead testing. When I get to the 3 point IR test on a single circuit should I switch off the breaker for that circuit .Hopefully I am correct in removing any lamps on a lighting circuit and turned switches on with all points closed. On a radial or final ring I have closed all points turned sockets on.
I think the procedure may be different when doing a global test, not sure.
Just a bit confused about the circuit breaker as I know it is switched on for continuity of cpc test.
Thanks in advance for any input

dead testing is what it says. all dead tests (continuity,polarity, and IR) are carried oit with the circuit/s isolated from supply. on new installations, these tests are done even before the circuits are connected or the CU powered up. don't confuse continuity with loop impedance. the latter is a "live" test.

 

[Thommo]

dead testing is what it says. all dead tests (continuity,polarity, and IR) are carried oit with the circuit/s isolated from supply. on new installations, these tests are done even before the circuits are connected or the CU powered up. don't confuse continuity with loop impedance. the latter is a "live" test.

Thanks telectrix,
Here’s why I am a bit confused.
Here’s a page from my notes I have been given. I have underlined the reason I am confused.

 

[ipf]

You can test circuits for IR individually, or globally. Globally with the breakers on, in order to link them together......more than one circuit, one test, as in many EICR's. Whichever, supply to the breakers must be isolated. It's a dead test.

 

[Thommo]

You can test circuits for IR individually, or globally. Globally with the breakers on, linking them together......all one test, as in many EICR's. Whichever, supply to the breakers must be isolated. It's a dead test.

So the answer contradicts my notes. And confirms the way I have been doing it this week, with circuit breaker in the off position

 

[ipf]

No, either way. With IR you're checking for clearance. If everything is 'clear' from each other with a global test, it's OK. If not, you have to split the circuits and test individually to find which is faulty.
With continuity, you can link the breakers, switched on, to earth. Then test at the end of circuit for continuity. If RFC's are involved, each circuit has to be done individually.
Whichever ways, the power is OFF.

 

[Thommo]

No, either way. With IR you're checking for clearance. If everything is 'clear' from each other with a global test, it's OK. If not, you have to split the circuits and test individually to find which is faulty.
With continuity, you can link the breakers, switched on, to earth. Then test at the end of circuit for continuity. If RFC's are involved, each circuit has to be done individually.
Whichever ways, the power is OFF.

Thanks ipf clarity . So I haven’t been doing it wrong then.

 

[ipf]

Thanks ipf clarity . So I haven’t been doing it wrong then.

It's the same IR test, one circuit or multiple at once. Just think about it.

 

[Thommo]

It's the same IR test, one circuit or multiple at once. Just think about it.

I have thought about it mate, probably too much. Just got a bit confused when I read that note.

 

[Strima]

Thanks telectrix,
Here’s why I am a bit confused.
Here’s a page from my notes I have been given. I have underlined the reason I am confused.

You might want to challenge your tutor on that as it potentially dangerous to carry out IR testing on live circuits.