Main 100A switch tripping

[Druncanduncan]

Visited a job today. Small shop. 'Lectrics are tripping out. Ok! Newly rewired due to the problem that still exists. New board 100A main switch. Not rcd. Board has 12 rcbos. Intermittent tripping. When it does trip it takes out main switch and ALL rcbos. Tncs system. Not widely experienced so have asked a number of people, nobody has heard of this happening. Any thoughts guys n gals? Appologies no photos as yet

 

[Druncanduncan]

Appreciate the comments so far. Obviously not enuff info yet. Just thought id try get some general feedback. Like i said ill be going back so will get alot more info then.

 

[Druncanduncan]

I see where your coming from adam and DPG

 

[Amp David]

Main switch tripping, first for everything i suppose[emoji41][emoji41][emoji41][emoji41][emoji41][emoji41]

 

[NDG Elecs]

I had a customer a cupla years back that swore blind the main switch on a 3036 board was 'tripping'.. Though I know they don't do that, I could not think of any possible reason why he would have lied about it. He didn't come across as being stupid, had nothing to hide, etc etc.

Only thing I could possibly think of is old contacts being worn and and any springs within being a bit lively. I still don't believe it though!

 

[Jay Sparks]

I had a customer a cupla years back that swore blind the main switch on a 3036 board was 'tripping'.. Though I know they don't do that, I could not think of any possible reason why he would have lied about it. He didn't come across as being stupid, had nothing to hide, etc etc.

Only thing I could possibly think of is old contacts being worn and and any springs within being a bit lively. I still don't believe it though!

Well.........what was it????

 

[Simonslimline]

Well.........what was it????

An RCD probably.

 

[David M]

Is it me? How can a switch that has to be physically operated operate on its own accord?

Surely for this to happen the switch must be extremely worn out and won't hold in the on position, or its broken. I would assume that such a problem would be an obvious fault to detect, as the switch would feel sloppy or loose?

 

[Druncanduncan]

Im a bit confuddled now. Im convinced what i looked at wasnt any type of rcd but obviously you guys are correct in saying a main switch would have to be physically operated and that it wouldnt 'trip' as such. Eager to get back and have a better look. Will post update incase any1 remains interested...feeling ill probably look quite stupid at the end but hey ho...off to specsavers we go

 

[Simonslimline]

Im a bit confuddled now. Im convinced what i looked at wasnt any type of rcd but obviously you guys are correct in saying a main switch would have to be physically operated and that it wouldnt 'trip' as such. Eager to get back and have a better look. Will post update incase any1 remains interested...feeling ill probably look quite stupid at the end but hey ho...off to specsavers we go

What make is this main switch?

 

[David M]

Im a bit confuddled now. Im convinced what i looked at wasnt any type of rcd but obviously you guys are correct in saying a main switch would have to be physically operated and that it wouldnt 'trip' as such. Eager to get back and have a better look. Will post update incase any1 remains interested...feeling ill probably look quite stupid at the end but hey ho...off to specsavers we go

It is most like going to be a RCD, maybe an old type. I very much doubt a 100A rated overload device would trip (unless faulty) under normal use, based on the loads you have stated.
What is the main earthing arrangement? Is it a TT system with perhaps an old 30 / 100mA trip that has not been replaced and kept in service as use as the main switch?

 

[Adam W]

It'd be worth asking a load of questions to get some background information:
Is there any pattern to when it all trips - in the middle of the night, when someone is in the shop watching it, certain times, when a certain appliance is being used, when a certain person is looking after the shop etc?
Is the cupboard actually, in all honesty, kept locked, or is it just supposed to be locked? Who has a key to this cupboard?

If the whole place has been rewired, as they say, then there's not much else it can be.

 

[Octopus]

I think a photo of said board would help immensely

 

[David M]

It'd be worth asking a load of questions to get some background information:
Is there any pattern to when it all trips - in the middle of the night, when someone is in the shop watching it, certain times, when a certain appliance is being used, when a certain person is looking after the shop etc?
Is the cupboard actually, in all honesty, kept locked, or is it just supposed to be locked? Who has a key to this cupboard?

If the whole place has been rewired, as they say, then there's not much else it can be.

Its very strange, you would assume that a full re-wire would include replacing all protection devices and include a new main switch in the new CCU??
If the installation has been tested correctly and is satisfactory then one would assume that it is an appliance or accessory causing the problem??

 

[NDG Elecs]

Is it me? How can a switch that has to be physically operated operate on its own accord?

Surely for this to happen the switch must be extremely worn out and won't hold in the on position, or its broken. I would assume that such a problem would be an obvious fault to detect, as the switch would feel sloppy or loose?

Yep I agree. The switch in the instance I talked about seemed normal when I tried switching it a few times. It didn't feel like it had more pull in one direction. When the bloke said it had tripped several times I said you must be getting sick of replacing the fuse wire...he said what fuse wire! To this day I am 99% sure he was somehow mixed up, but I do have a niggling doubt...

 

[NDG Elecs]

Well.........what was it????

Don't know Jay is the only answer I can give! The fault had cleared when I attended as there had been water getting in through the roof causing the cough-splutter tripping cough- splutter..

I was there to check over the light fittings primarily to see if they were dry and OK etc..