Supposed Fault On Merlin Gerin Dis Board

[R G]

Hi All,
Here's a new one , has anybody heard of a Merlin Gerin 3 phase dis board self destructing , the story goes that the Electrician working on it had a phase to phase short within the central enclosure ie between the bus bars , this is the story I was told about , I must admit I and many others find hard to believe , the consequences are that 2 x supply fuses were taken out and caused an allmighty explosion when the front cover was re fitted

 

[mark ju]

Did it involve perhaps the use of a holesaw on the top plate of the DB? Only ask as i know someone who killed a board in a hospital by letting the piece from inside the holesaw drop down inside. Careless!
Obviously he had not isolated the board.
Story also goes that he actually s##t himself!

 

[guest119]

That is why I have Q Max cutters in my kit.
20mm, 25mm, 32mm, 40mm, 51mm, very cheap on E Blag.


Boydy

 

[JD6400]

Did it involve perhaps the use of a holesaw on the top plate of the DB? Only ask as i know someone who killed a board in a hospital by letting the piece from inside the holesaw drop down inside. Careless!
Obviously he had not isolated the board.
Story also goes that he actually s##t himself!

I just love that last line !:willy_nilly:

 

[Darkwood]

The early generation of merlin D-boards were similar to modern but with a big flaw the busbar link from the main switch to the main central busbar rise were exposed on the rear but not on the front... now if you passed a exposed copper wire across the space behind the busbar riser(a unsleeved earth wire) you could short out the incoming links and if it had a standard main switch as oppose to a mccb and the front end was the DNO fuses then it can set the main switch into a firework display and take out the incoming....

I see so many comments saying it a load of bull but try not to give a focused opinion if your experience in the industry isn't long try sit back and learn from the more established members ....we dont know everything but we can enlighten you to things you never realised.

 

[R G]

Hi All
Thanks all for the response , as I said I would like to have seen the dis board and quite possibly come up with the same conclusions , but it seems it would be great for all of us to be aware of this situation , just in case we come across it .
Many Thanks All Ray Galea

 

[Robotstar5]

and today I was telling my new boss how good MG isobar boards were!, will I have to retract the statement tomorrow?

 

[Darkwood]

It only effects the older generation boards as they quickly realised the dangers that exist with the unseen exposed busbars modern boards are fully insulated or inaccessable even at the space behind the switch and busbar system.... remember most sparkies were passing wires down the back when adding new circuits and those who are unaware might put their hand behind or push a bare earth across as i believe has happened in the OP mates case.