Dual RCD

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Sharpend

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Because strictly speaking they are not.
I don’t remember the exact wording but it relates to minimising disruption, nuisance tripping of other circuits, how can this be achieved with a single RCD protecting multiple circuits? It’s in the regs, I’m sure one of my learned colleagues will be along shortly with reg reference.
 

binky

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Because strictly speaking they are not.
I don’t remember the exact wording but it relates to minimising disruption, nuisance tripping of other circuits, how can this be achieved with a single RCD protecting multiple circuits? It’s in the regs, I’m sure one of my learned colleagues will be along shortly with reg reference.
That's the nub of it without going into another long discussion on the subject.
 

Fleeting

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Regulation 531.3.2 was introduced into the first 18th Ed which permits subdivision of circuits and an individual RCD however you are asked to consider Section 314.
So are they compliant, yes according to Regulation 531.3.2 providing a considered approach is employed.
 

peterspurs

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Regulation 531.3.2 was introduced into the first 18th Ed which permits subdivision of circuits and an individual RCD however you are asked to consider Section 314.
So are they compliant, yes according to Regulation 531.3.2 providing a considered approach is employed.
 
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314.1, 314.2, 314.3 and 314.4

plus there is the thorny issue of making sure that the earth leakage is below 10 mA (IIRC) per RCD / RCBO

And no competent spark installs dual RCD boards any more ....................

1 circuit fault = losing 1/2 the circuits.

Takes longer to identify the faulty circuit and causes too many problem and costs more to diagnose and fix
 
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Why do some people say they are non compliant when they are?

There are some people who only ever do installation work..
and use the "install cheap, disappear, never to return" method of customer service..
So they cannot grasp the understanding of how poor a dual RCD design is.. (if you can even call it a design).

If you've ever done fault investigations where an installation is experiencing, random intermittent tripping on a dual RCD board..

Or you have a customer unable to reset an RCD because of a neutral to earth short after a cable was damaged..
and is now unable to energise half of their installation.. (including the freezer & the internet router and the electric garage door etc..)

You soon realise how expensive the remedial fault finding labour and inconvenience factor is to a customer...
and how much cheaper and batter value a full RCBO board is...

Why would any competent person even consider such a poor solution for a prospective customer,
when there is a much better solution available?
 

Geoff1946

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f you've ever done fault investigations where an installation is experiencing, random intermittent tripping on a dual RCD board..
I did once help out, (whilst on holiday, I add) with some fault finding in France. There was only one RCD, if I recall correctly.
The MCBs, same appearance and size as ours, were all double pole. What a huge advantage for fault tracing!
Why are UK ones only single pole?
 

peterspurs

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The question was about regs not if they are any good
Yes we have all come across RCDs tripping and people losing half there house a pain but not rocket science to repair.
If the customer doesn’t want to pay the extra £200 for RCBOs it’s on them
I don’t use them as a rule but preference is not a regulation
Regulation 531.3.2
 
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The question was about regs not if they are any good
Yes we have all come across RCDs tripping and people losing half there house a pain but not rocket science to repair.
If the customer doesn’t want to pay the extra £200 for RCBOs it’s on them
I don’t use them as a rule but preference is not a regulation
Regulation 531.3.2

Extra £200 ??

Your pricing is well out of date
 

peterspurs

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I did once help out, (whilst on holiday, I add) with some fault finding in France. There was only one RCD, if I recall correctly.
The MCBs, same appearance and size as ours, were all double pole. What a huge advantage for fault tracing!
Why are UK ones only single pole?
You can get them now double pole rcbo single module fuse box
Extra £200 ??

Your pricing is well out of date
Really it was a figure and how is it so out of date when there is no information how many ways for example
 

binky

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The question was about regs not if they are any good
Yes we have all come across RCDs tripping and people losing half there house a pain but not rocket science to repair.
If the customer doesn’t want to pay the extra £200 for RCBOs it’s on them
I don’t use them as a rule but preference is not a regulation
Regulation 531.3.2
You are looking at around £10 extra per circuit. Given that many electricians are charging £800+ for a board change, it's not a lot more.
 
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