!..Burnt our MCB at busbar end..!

[se7aq]

Hello
I have just changed two MCB's on a CU, the 32A was burnt out on busbar end and the 16A next to it was also burnt due its proximity. Why did this happen. could it have been tightened to tight or is there a more sinister explanation?

 

[Brightspark2]

MCB not clamped onto bus bar?...

 

[kingeri]

Loose connection or Wylex MCB!

 

[Plonker 3]

Faulty MCB.
Loose connection.
Direct heat source placed close to MCB.

 

[chrish_1977]

Beat me too it brightspark2

 

[Plonker 3]

I do like the thought something more sinister could cause this too happen.

 

[oldtimer]

Loose connection usually shows up on load circuits ie immersion and shower , cooker and why because the guy who connected them up either had a worn screwdriver or he could not be bothered

 

[Guest112]

that's why you always check the busbar side before energising, I have seen in the past some dodgy mcbs that seem to have been overtightened and ruined the threads on the clamps

 

[Darkwood]

Most likely as already said the mcb clamp that grabs the busbar hasn't got a blocking lip on it this allows the busbar tongue to insert behind the clamp and not make a proper connection.

 

[SPARTYKUS]

Beelzebubs work.

 

[mark ju]

or is there a more sinister explanation?

Yes there is in fact a sinister explanation for this.
It is obvious to me that extra terrestials are using your distrubution board to channel their radio signals to their home world.
This can be avoided by turning the DB off at the main switch for twenty four hours. Wrapping it in tin foil will also help.
Ignore all other comments, these are forum users just trying to set your mind at ease. i dont do things like that.

 

[markc123]

mark ju, lol ?

 

[oldtimer]

Also if inside the CU its good practice to check the connections and I mean check not overtighten