MCB tripping.

Photos and a sketch of the circuit would clarify matters a lot

Pretty clear to me he has put a 32A switch into the ring final by way of a 4.0 radial.

Fleeting said:

Pretty clear to me he has put a 32A switch into the ring final by way of a 4.0 radial.

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That’s what I suspect but the OP isn’t really coming forward with clarity

Fleeting said:

Pretty clear to me he has put a 32A switch into the ring final by way of a 4.0 radial.

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He explained:
It is...MCB to 32A switch to final ring using a 4mm radial.

He does not say how he connected the radial into the final ring. I assume using a junction box. If the above is done then no problems. If problems, then the switch looks defective, being the only meaningful addition.

John Burns said:

He does not say how he connected the radial into the final ring.

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Which is why I asked a question earlier on that the OP concluded they didn’t need to answer

Tim Artingstall said:

Thanks for all your comments although none seem very helpfull, all equipment is individually swtiched off with the exception of 1 small negative ion generator and 3 small dc transformers no more than 0.5amp each. If it was in rush current (which it isnt) the mcb would trip when I switched it back on, which it doesnt. The circuit itself is fault free Ive checked it ( I have 2391). I think perhaps the best answer is to change the MCB and the 32smp switch, which does seem a bit clunky. Changing for a motor rated breaker seems a bit pointless as there is virtually no start up load.

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Hi Tim.
Even if none seem very helpful, it's maybe best to keep that thought to yourself, it just riles people up and leads to even less helpful answers, meaning you lose out.
It's an interesting problem! I have never come across it before. I can see you're not too happy with some of the replies, but do try and come back to us when you have found the solution as it would be great to know why it happened. I'm sure everyone will give you a friendly 'like'

️

Murdoch said:

Dare I asked what testing you have done ?

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Murdoch said:

Photos and a sketch of the circuit would clarify matters a lot

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Fleeting said:

Pretty clear to me he has put a 32A switch into the ring final by way of a 4.0 radial.

Click to expand...

Murdoch said:

That’s what I suspect but the OP isn’t really coming forward with clarity

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We never did actually get any useful test results... Or sketches/photos... to assist with trying to offer much practical advice...?

Its a bit like working with one-hand tied behind your back when someone asks for help..
You ask for a bit more detail / clarification.. But they ignore your requests thinking of them as irrelevant!

Back in my younger days if trying to figure out a tricky fault.... If I ever asked for assistance with a problem..
My work colleagues, superiors, line managers etc... always suggested something along the lines of:-

Draw the circuit out.. (either block, wiring or schematic diagram dependent upon which is most suitable)..
And write onto it all of the test results you have taken, with cable sizes, approx lengths if known, at all relevant positions on the drawing...

This can make it so much easier for someone else to evaluate your testing either at the office..
or to recreate / retest it on site..

Even now many years on.. working as a sole trader..
I still make sketches on my A4 note pad with my results written at all relevant points when doing fault investigations.

Perhaps its just me...
But I struggle to understand how someone who claims to have many years of electrical experience, cannot understand why, or offer any more specific test results and/or a wiring diagram.??? { confused.com }

Disconnect the ring. Put a lamp as load on o/p of switch, does it trip, if yes switch duff. If not break ring half way, connect one side of ring then the other side, one side will probably take it out the fault is on that leg, then narrow it down further.