3 phase problem after spark did 5 year safety inspection

[jimthegent]

Hi lads 5 year safety inspection the spark put the tails back and later line 2 of the 3 phase blew blowing the box off the wall and taking out the main fuse on the same line into the building can you all just say quickly what you think the spark may have done wrong ?
Cheers

 

[jimthegent]

How do you know your system is perfectly balanced? Why is that board fed in tails? Generally heavily loaded single phase boards would indicate the system is unbalanced in my experience. I can’t really see why the spark had the tails out for testing either, just doesn’t really make sense.

Edit- no answer to my previous question either, did the cover actually blow off? How did that happen with threaded screws on the cover, did they break? Do you have a picture?

There's a pic of inside the box there's black all up the rhs and inside it's black and scorched

 

[jimthegent]

How do you know your system is perfectly balanced? Why is that board fed in tails? Generally heavily loaded single phase boards would indicate the system is unbalanced in my experience. I can’t really see why the spark had the tails out for testing either, just doesn’t really make sense.

Edit- no answer to my previous question either, did the cover actually blow off? How did that happen with threaded screws on the cover, did they break? Do you have a picture?

 

[jimthegent]

How do you know your system is perfectly balanced? Why is that board fed in tails? Generally heavily loaded single phase boards would indicate the system is unbalanced in my experience. I can’t really see why the spark had the tails out for testing either, just doesn’t really make sense.

Edit- no answer to my previous question either, did the cover actually blow off? How did that happen with threaded screws on the cover, did they break? Do you have a picture?

There's the best I can get of the burnt tail after it has been taken our

 

[suffolkspark]

View attachment 112423

But thats all hanging off that single phase board, so i dont get why you keep talking about phase balancing? How many amps are each of those servers drawing? If the full or near to the 16A that is mighty loaded, With that board connected straight off the henleys i wonder what the upfront main fuses are. Are they greater than 100A?

 

[jimthegent]

But thats all hanging off that single phase board, so i dont get why you keep talking about phase balancing? How many amps are each of those servers drawing? If the full or near to the 16A that is mighty loaded, With that board connected straight off the henleys i wonder what the upfront main fuses are. Are they greater than 100A?

Hi 5 amps a unit and yes the fuses are 100amp per phase there's a small drawn through the main board to run the fans but it's tiny

 

[jimthegent]

Hi 5 amps a unit and yes the fuses are 100amp per phase there's a small drawn through the main board to run the fans but it's tiny

They servers all run on low power setting

 

[suffolkspark]

They servers all run on low power setting

How many amps each?

 

[jimthegent]

How many amps each?

Hi I can't promise this is dead right but each units is 1500 w

 

[suffolkspark]

Hi I can't promise this is dead right but each units is 1500 w

One on each socket?

 

[jimthegent]

One on each socket?

Yeah and we'd have 5 to 8 running at any one time

 

[jimthegent]

Yeah and we'd have 5 to 8 running at any one time

We are talking 12kw at the top end no more than that a 1kw for other bumfluffery fans main server lights etc

 

[jimthegent]

One on each socket?

I'm not ruining your Christmas here am I mate ? More than happy to leave this till mid week if your dinners going cold

 

[suffolkspark]

I'm not ruining your Christmas here am I mate ? More than happy to leave this till mid week if your dinners going cold

I just dip in and out of here when i get a sec, i really have no further ideas, thats not a massive load if all is well, but hefty if there was a poor main switch or loose wire

 

[jimthegent]

I just dip in and out of here when i get a sec, i really have no further ideas, thats not a massive load if all is well, but hefty if there was a poor main switch or loose wire

True there is a higher draw at start up as we need to get the building down to optimum temp and the fans on the machines work harder until we reach equilibrium but a loose wire is a disaster no matter what the load is isn't it

 

[DefyG]

True there is a higher draw at start up as we need to get the building down to optimum temp and the fans on the machines work harder until we reach equilibrium but a loose wire is a disaster no matter what the load is isn't it

I still maintain its nothing to do with a balanced or unbalanced 3phase load.
I do not think it is an overload (you dont get flash/bangs like that and molten copper from an overload)
IMHO Its a L - E or N 'Dead Short'