Electric Panel Blow Up

Way too vague.

What have you investigated so far?

Too much current? Water in the panel, either from the outside or from condensation? Metal filings left over from installation? Spider webs? Mice? Lightning strikes? Regeneration from something down stream? The list of potential problems is endless really. Narrow it down a bit.

Where is it located? What is it feeding? When does this happen? etc. etc. etc. You are not charged by the word here, go ahead and use them.

Apparantly there seems to be dead short circuit on the bus connecting the the incomer breaker and the bus.Please isolate the braker and visually examine the panel for damages .Isolate all the outgoing feeders and check the insulation resistance values between phases and neutral and earth .If the values are low take remdial action.

To sortout the proublem ask Sevice Engineer to verify the circuit breaker Arc chute,Moving contact, Cluster etc., If possible replace the wornout parts otherwise completly the breaker has to be replaced by new one. Please dont take risk on this.Before that also ensure the tightness, current rating , Busbar check, current Transformer test to be carried out throughly.

Any chance of transient voltages sufficient to ionize the air across
the phase to phase gaps in the areas you mention?

Is there a lightning surge supressor on the system?

As I go over your letter, I can sense that your lugs is in loose contact state. This may caused by loose thread lugs or rusted portion of your contact points. Thorough Physical examination will surely provide you answers and solution of your problem.

Blowing up? There's a BIG difference between blowing up and burning up. How old is the equipment? Most things oxidize, and that can cause heat at connections. Loose connections caused by heating and cooling cycles allow air to come in contact with what used to be good metal to metal seals, oxidation occurs (heat helps process), and before long, you got problems. If it actually blew up, there was probably a catastrophic failure somewhere that damaged the panels. I'd bet age is the main culprit, even though you didn't say anything about how old the stuff is.

Ok lets assume (bad to do) that the the droppers are the spring loaded bus connections feeding the cell which are connected to the movable cell bus. Alot of times what happens with age is the fingers don't line up because of loss of tension from the springs wear out . This causes hot connections ; which of course translates into damage down the road . The sub yyou are talking about needs going over thoroughly (cleaned and breakers serviced ) . Has the Mcc's themselves out of the sub ever been Pm'd for tightness, cleanliness whether the buss insulators on the sub are free from debris . Blowing up ...once maybe ,twice too much, anymore fix the problem or get a breaker specialty into to do the deed don't just keep guessing until the whole Mcc center takes you with it !!!!

Quality pictures on a web site might be a good idea.....and more infos.