mk rcbo failure

[photon]

Tested some of the RCBO's in my consumer unit today by pressing the test buttons.

(we all do this every so often like we should , don't we )

Anyway one of the units did not trip , started to arc (nasty buzzing) and acrid white smoke poured out around the flip switch.
(2 hours later the smell has just about gone !!!)

Luckily I had a spare unit so it is now swapped out and the new one is working (and testing) fine.

I have never come across a failure of this type before and was wondering if it had happened to others.

It is a 32 amp Mk module

 

[JohnD]

Not me.

I did mine the other day after reading the article on RCDs tested "once a year or never" failing to trip reliably. Ones tested monthly are much more reliable.

 

[securespark]

Yeah I had a Square D one do this about 12m ago.

Pressed the button to test it, there was an almighty bang & loads of smoke. Thought I was going to have to call the brigade out...

 

[JohnD]

Would be interesting to cut one open and see what happened.

 

[plugwash]

Thought I was going to have to call the brigade out...

Electrical stuff is made of self extinguishing plastics for a reason!