Discuss RCBO intermittent tripping advise?? in the UK Electrical Forum area at ElectriciansForums.net
Why would a type D 'probably be non compliant in a lot of domestic situations'?There's your answer then, a D type is most unusual and probably non compliant in a lot of domestic situations, I expect the new RCBO serving the kitchen lights will have a 'B' tripping curve, if the customer doesn't agree to new LED lights a C type 10a RCBO might do the trick.
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The D type MCBs were originally fitted to counteract the high inrush current and nuisance tripping with the old toroidal transformers I expect.
Why would a type D 'probably be non compliant in a lot of domestic situations'?
If the measured Zs is satisfactory.....and anyway the OP stated there was originally an RCD main switch which largely negates any OCPD Zs issues.
Hardly ever, doesn't mean they are likely to be non compliant though.How often have you seen type D MCBs in domestic installations ?
I would say a 6A D type MCB or RCBO would have a 50% (approx) chance of being non compliant in a domestic situation as the Zs would have to be max 1.46Ω (TT).Hardly ever, doesn't mean they are likely to be non compliant though.
I assume you mean TN....not TT? Any rating of type D would have a 100% chance of being compliant in a correctly designed TT.I would say a 6A D type MCB or RCBO would have a 50% (approx) chance of being non compliant in a domestic situation as the Zs would have to be max 1.46Ω (TT).
I would say a 32A D type MCB or RCBO would have a 98% (approx) chance of being non compliant in a domestic situation as max Zs is 0.28Ω (TT).
My aspergery brain starts overheating when the word 'likely' is used as it is so subjective! It doesn't mean anything in this scenario. Even my approximations above are ridiculous as they are only ever so slightly less subjective.
It's a bit like that old 80's film 'war games' when the computer tries to find a winner in nuclear war and breaks down due to infinite 'no win' outcomes.
I will now stop drinking coffee.
But that doesn't make it non compliant. Sorry but I get irritated by this, I've even heard talk in the wholesalers that only type B is permitted in domestics. That's how these phantom regs come aboutAnd now you're saying pretty much what I was getting at, bottom line is that a type D is not a good design choice for a new domestic install.
Each transformer has eight sets of T&E going to it can’t be arsed if I’m honest now!!Why not swap the kitchen transformer with one of the other identical units and see if the fault moves.
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