Dead RCBO? or Brain fart

[Andy Walker]

This could just be a Friday evening brain fart after a long week but,
Got home tonight to find the downstairs lighting cicuit has tripped, tried to reset the RCBO and it blew again straight away. IR tested the circuit, all fine.
While the circuit was disconnected I tried turning the rcbo on and re-energising the board and RCBO trips again. I took the neutral flying lead out of the neutral bar and RCBO doesn't trip. Like I say, could be my brain isn't functioning correctly and I'm missing something obvious or has the RCBO failed? Any thoughts appreciated.

 

[Pete999]

This could just be a Friday evening brain fart after a long week but,
Got home tonight to find the downstairs lighting cicuit has tripped, tried to reset the RCBO and it blew again straight away. IR tested the circuit, all fine.
While the circuit was disconnected I tried turning the rcbo on and re-energising the board and RCBO trips again. I took the neutral flying lead out of the neutral bar and RCBO doesn't trip. Like I say, could be my brain isn't functioning correctly and I'm missing something obvious or has the RCBO failed? Any thoughts appreciated.

What IR tests did you carry out L-E, N-E, L-N? and what were the results?were all of the circuit under test dissed from the CU?

 

[Deleted member 9648]

Without the circuit connected to the load terminals of the RCBO it would seem that a faulty RCBO is the only explanation.

 

[Marvo]

Same as Wirepuller, if it trips with circuit live and neutral disconnected replace it with a new one.

 

[Andy Walker]

Pete, did all L-E, N-E and L-N all >400MOhm. Circuit I tested was disconnected from the CU.

 

[Toneyz]

I had a faulty MCB the other day where there had been a L-N short in a pull cord and they had tried turning it back on so the KA had got the better of it.

 

[Toneyz]

Pete, did all L-E, N-E and L-N all >400MOhm. Circuit I tested was disconnected from the CU.

Not the earth though?

 

[Andy Walker]

Cpc of the circuit was disconnected too

 

[westward10]

Sounds like the rcbo if it does it without the circuit connected, as already stated. Have you tried connecting it to another rcbo in the board.

 

[Andy Walker]

Yeah, connected the circuit to another RCBO and it's working fine.