Buzzing RCBO

[Deleted member 9648]

Update.
Swapped the RCBO this morning and the new one buzzed exactly the same. Unfortunately there was no access to the rooms untill tomorrow morning so further investigation had to wait but at least the possibility of a faulty breaker has been eliminated.
Thanks again for the suggestions of causes,will be going round tomorrow unplugging/disconnecting loads and try to pin it down that way. If that doesnt work some more extensive testing may be required.

 

[Marvo]

It's the kind of issue that you'll probably find by elimination, ie unplugging or disconnecting loads rather than actual testing. TBH if RCBO is not getting warmer than usual I wouldn't worry about it, it's not something that's likely to be a safety issue, just an anomaly or an annoyance at worst.

 

[Farmelectrics]

Did you try moving the rcbo away from the breakers next to it

 

[Deleted member 9648]

Sorted.
Tracked down an FCU on the ring serving two high level son floods, neither of which have apparently worked for some time. As soon as these were disconnected the buzzing ceased and resumed when re-instated. I'll leave the technicalities of how these affected the RCBO to those with more technical knowledge than myself,as no further investigation was carried out. They were left disconnected pending replacement with 50w LED floods.

 

[Darkwood]

Possible the striker constantly trying to strike a duff lamp at a guess or a ballast sat energised generating a few transients back down the circuit... like I say just a guess.

 

[Lucien Nunes]

Aha so I was fairly close with my florry ballast suggestion. I'm with DW it was probably the igniter just breaking over, generating nice little current spikes without using any real power. Glad you found it.

 

[Marvo]

Sorted.
Tracked down an FCU on the ring serving two high level son floods, neither of which have apparently worked for some time. As soon as these were disconnected the buzzing ceased and resumed when re-instated. I'll leave the technicalities of how these affected the RCBO to those with more technical knowledge than myself,as no further investigation was carried out. They were left disconnected pending replacement with 50w LED floods.

Glad you found it and thanks for letting us know, it's one of those little interesting ones I'll remember for next time I get a buzzing protective device.