Periodic IR testing

[LVSparks]

Hello all.
When conducting IR tests on condition reports, with L-N connected together and testing to earth. What equipment have you found will still cause the readings to be 0.00?

 

[HandySparks]

Hello all.
When conducting IR tests on condition reports, with L-N connected together and testing to earth. What equipment have you found will still cause the readings to be 0.00?

None, unless it's faulty.

An RCD spur or RCD socket can give a low IR measurement to earth, but not 0.00 Mohm.

 

[Octopus]

Did you switch off the main switch or just the MCB's?

 

[Pete999]

Did you switch off the main switch or just the MCB's?

I hope the answer will be the Main Switch with a dirty great big lock on it

 

[LVSparks]

I hope the answer will be the Main Switch with a dirty great big lock on it

Tested with main switch off.
Didnt disconnect any current using equipment.
There are no rcds.

 

[NDG Elecs]

Where in the install did you do the IR test? At the board I hope. If tested correctly then there is a fault. Test L-CPC and N-CPC to eliminate one or the other.

If it was tested at a socket etc then even with MCB open think PME could be the cause.

 

[NDG Elecs]

Well sounds like an appliance or the circuit has got an earth fault. Needs sorting.

 

[LVSparks]

Just had another look in this board, didn't realise there was a neutral link behind the main switch cover. It's a been converted to single phase from three.
So with the main neutral disconnected this time, testing the same way as before and testing each circuit individually I'm getting 0.23 on every circuit.
A couple test greater than >999 L-E but L with N together to E was 0.23.
Whats your thoughts fellas?

 

[Leesparkykent]

Just had another look in this board, didn't realise there was a neutral link behind the main switch cover. It's a been converted to single phase from three.
So with the main neutral disconnected this time, testing the same way as before and testing each circuit individually I'm getting 0.23 on every circuit.
A couple test greater than >999 L-E but L with N together to E was 0.23.
Whats your thoughts fellas?

Further investigation needed.

 

[not clever]

+1 on the FI needed

 

[HandySparks]

Just had another look in this board, didn't realise there was a neutral link behind the main switch cover. It's a been converted to single phase from three.
So with the main neutral disconnected this time, testing the same way as before and testing each circuit individually I'm getting 0.23 on every circuit.
A couple test greater than >999 L-E but L with N together to E was 0.23.
Whats your thoughts fellas?

Is this with each final circuit neutral disconnected and line disconnected (or circuit breaker opened)?

 

[LVSparks]

Sorry for the delayed.
This was tested with the main neutral disconnected but all circuit neutrals still connected.