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

 

[suffolkspark]

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

Why did the spark have the tails out for an inspection?

 

[jimthegent]

Why did the spark have the tails out for an inspection?

No idea but it's a local council job so I assume because they can bill them for more dough

 

[suffolkspark]

No idea but it's a local council job so I assume because they can bill them for more dough

Are you sure he actually did remove them? He should have spotted a loose connection when checking all the terminals though, thats if it was that and not faulty contacts in the switch.

 

[jimthegent]

Are you sure he actually did remove them? He should have spotted a loose connection when checking all the terminals though, thats if it was that and not faulty contacts in the switch.

Yes 100% he took them out and put them back in again

 

[westward10]

I would say a dead short has occurred there.

 

[jimthegent]

I would say a dead short has occurred there.

Yeah and what do you think caused it

 

[westward10]

There is molten metal albeit it doesn't look like copper, the remains of something else?

 

[snowhead]

Looks like the Red clamp has squashed the cable and split the insulation.
That's allowed the copper core to touch the earthed metal backplate and or the screw holding the clamp.

If it was the cable lose in the terminal or wrong side of termianl clamp it would have fizzled and overheated for a while before ultimately failing.

As Westwood, it looks like a dead short, especially with the ball of copper

 

[jimthegent]

There is molten metal albeit it doesn't look like copper, the remains of something else?

Yes the cover of the board was blown off and there's a lot of black soot all over the switches so clearly a lot of heat was generated

 

[plugsandsparks]

Cable clamp look suspicious....

 

[jimthegent]

Looks like the Red clamp has squashed the cable and split the insulation.
That's allowed the copper core to touch the earthed metal backplate and or the screw holding the clamp.

If it was the cable lose in the terminal or wrong side of termianl clamp it would have fizzled and overheated for a while before ultimately failing.

As Westwood, it looks like a dead short, especially with the ball of copper

Yep now bear in mind all other tails and switches are pristine is there any votes for system overload the main fuse that blew into the building is also on phase 2

 

[westward10]

It is a dead short. Can you show a more direct pic below the red clamp.

 

[plugsandsparks]

Not overload, short cct fault as WW states

 

[jimthegent]

It is a dead short. Can you show a more direct pic below the red clamp.

 

[plugsandsparks]

Needs to be powered down and clamp removed, i can see it is already pinching the RHS cable sheath.

Once clamp removed photograph the back side of it, remove the LHS cable and photographc the back plain of board, should tell you everything you need to know, Merry Xmas

 

[jimthegent]

It is a dead short. Can you show a more direct pic below the red clamp.

Hi no they can back and replaced the switch and tail and removed the offending bits

 

[suffolkspark]

Ah so its all sorted....

 

[jimthegent]

Ah so its all sorted....

Seems the wire being nipped seems to be winning the vote can any of you guys see a situation were a nicely balanced 3 phase which was always well well under max amps would see just one phase go up like this

 

[jimthegent]

Ah so its all sorted....

Yeah but the upshot was that we were running on 2 phases for a a good few hours the fans failed the temp in the building rocketed and a load of other problems as a result

 

[jimthegent]

Needs to be powered down and clamp removed, i can see it is already pinching the RHS cable sheath.

Once clamp removed photograph the back side of it, remove the LHS cable and photographc the back plain of board, should tell you everything you need to know, Merry Xmas

Hi can't thank you enough for the advice what would photos of the back of the clamp and board show or what should I look for ?

 

[westward10]

What did they say caused it.

 

[jimthegent]

What did they say caused it.

An overloaded board but it's run fine for 5 years and it just happend to blow a few hours after they wiggled the wires plus each phase is perfectly balanced with 9 feeds

 

[jimthegent]

What did they say caused it.

I've attached a picture of were the feeds are they are the ones on the rhs blue ones

 

[westward10]

An overloaded board but it's run fine for 5 years and it just happend to blow a few hours after they wiggled the wires plus each phase is perfectly balanced with 9 feeds

That wasn't an overload that was a dead short, a short they created.

 

[snowhead]

An overloaded board but it's run fine for 5 years

So is it still "overloaded" or has that been corrected?

 

[jimthegent]

That wasn't an overload that was a dead short, a short they created.

Thanks again pal really appreciate it

 

[jimthegent]

So is it still "overloaded" or has that been corrected?

Never was plus there's breakers on the pdus there's 9 sockets and we are always on about 50% of max amps the units cooling runs on a separate board and there's no other power pulls plus it's winter so the system isn't stressed due to high temps

 

[pc1966]

Cable clamp look suspicious....

It looks too small for that wire size, or is it just fitted strangely?

 

[jimthegent]

It looks too small for that wire size, or is it just fitted strangely?

You getting warm mate not as warm as that tail got the consensus seems to be the outer casing got nipped when refitting but I'm seeing if any sparks have another take on it