All devices on 3phase board tripped simultaneously

[Chris White]

A customer recently lost power to part of their electrical installation. On arrival I found all IEC 60947-3 devices had supposedly tripped - including the main switch rated at In 400A. Excluding the possibility of someone tapering with the board, can anyone think of any other reason why this may have occurred?

 

[westward10]

Do you mean 60947-2. All devices had tripped, single and/or triple-pole.

 

[freddo]

Extreme over voltage? Does the connected equipment still work?

 

[Chris White]

Sorry for the typo, yes 60947-2. There were 6 three phase/3pole devices, 5 single pole devices and the main 3 pole switch. All of which I found in the off position. No sign of overheating/overload or smell, and I was onsite within 10 minutes of power loss.

 

[Yozza19]

I would say if the main switch was of someone has tampered with the board

 

[westward10]

I assume the main switch is also 60947-2.

 

[ipf]

With you saying part of the installation, is it a sub board?

Whatever, very a strange for all breakers to have tripped and the main switch to be in the off position.
Sounds like a manual job, to me.

 

[Chris White]

Extreme over voltage? Does the connected equipment still work?

 

[Chris White]

Yep, everything still works and nothing else tripped on any of the other distribution boards down stream of this board.

 

[Chris White]

With you saying part of the installation, is it a sub board?

Whatever, very a strange for all breakers to have tripped and the main switch to be in the off position.
Sounds like a manual job, to me.

It's actually the main board for one of the two three phase supply's coming into the building. I agree that it sounds like someone has tampered with it; however, my customer is adamant this could not have happened.

 

[westward10]

Is the main switch 60947-2 or 60947-3.

 

[pc1966]

Is the main switch just a switch so it has to be manually operated, or is it some MCCB that could have tripped due to an electrical incident?

 

[timhoward]

nothing else tripped on any of the other distribution boards down stream of this board.

Leaving the main switch aside, unless something simultaneously affected every single distribution circuit between this board in question and the downstream boards, it surely has to be manual operation.

What sort of cables are feeding the downstream boards, are they mechanically protected?
I have once found several circuits all chafed on poorly installed metal trunking which then got hit causing it to cut into all of them.
I think I'd IR a couple of the distribution circuits, rule out cable damage, and declare that the only logical reason is manual operation.

 

[nicebutdim]

Do you mean 60947-2. All devices had tripped, single and/or triple-pole.

Am I right in thinking that 60947-2 could incorporate over current protection?

It seems the OP isn't paying heed to your question.

 

[westward10]

Am I right in thinking that 60947-2 could incorporate over current protection?

It seems the OP isn't paying heed to your question.

Yes you are correct. 60647-3 is an isolator whereas 60947-2 is an mccb often used as main switches on panel boards.