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However, if an NE fault occurs on a group of circuits that are protected by a double pole RCD and an NE fault occurs it will disconnect the group of circuits, this inconvenience is NOT minimised.

End of.

 
However, if an NE fault occurs on a group of circuits that are protected by a double pole RCD and an NE fault occurs it will disconnect the group of circuits, this inconvenience is NOT minimised.

End of.
a split load board is allowed and minimized.

under the worst case scenario with two rcd's and an rcbo the rcbo should still have power going to it if the two 30ma rcd's trip.

so your saying practically every domestic install for over 10 years doesnt comply with the regs to minimize inconvenience 

 
a 100ma s type shouldnt trip in a split load board.

the 30ma should trip in 50ms while the 100ma s type shouldnt trip in less than 200ms if i remember right
You still haven't provided DP disconnection under fault conditions though. 

a split load board is allowed and minimized.

under the worst case scenario with two rcd's and an rcbo the rcbo should still have power going to it if the two 30ma rcd's trip.

so your saying practically every domestic install for over 10 years doesnt comply with the regs to minimize inconvenience 
No, this is very specific to TT,

but in general, dual RCD boards do NOT comply with minimising inconvenience under fault conditions, they are a mash up due to cost mainly, imho. 

 
a split load board is allowed and minimized.

under the worst case scenario with two rcd's and an rcbo the rcbo should still have power going to it if the two 30ma rcd's trip.

so your saying practically every domestic install for over 10 years doesnt comply with the regs to minimize inconvenience 


Yes I am and if you are really willing to pay my consultancy fees, I will prove it all the way to Strasbourg if you like.

 
Not one 16th edition consumer unit complied with the regulations, just merely a compromise agreed amongst those who govern us.

 
Not really agreed Manator, merely foisted upon us.

Well, not even foisted, just taken as OK without question, whether it was right or wrong.

It was wrong, but no one who had the power, had the guts to question it.

Lord only knows why, because the solution is a total bodge.

 
This has raised a Q now, 

Do SP RCBOs comply under TN,? 

I'm thinking they do as DP disconnection isn't required in the same manner under fault in TN.

 
Not really agreed Manator, merely foisted upon us.

Well, not even foisted, just taken as OK without question, whether it was right or wrong.

It was wrong, but no one who had the power, had the guts to question it.

Lord only knows why, because the solution is a total bodge.
it was probably allowed because of the cost, rcbo's for say schneider acti9 cost £30 each even for say bg there £18 each compared to £3.50 for an mcb

it makes a massive difference in cost, would anyone have a fuseboard change unless that absolutely had to if the board change would cost them over £200 just for the board

 
Ahh, now there is another myth.

Look up the full technical spec on an Acti9 RCBO, some homework for you.

Yes cost is a valid factor, however, not, in all circumstances.

Some requirements are absolute, even though they are not definitively specified in BS7671, this is one of the reasons for the changes in Amd3, these requirements have been in place for over 10 years now, in statute law, but have not been explicit in BS7671 so sparks have ignored them.

Thus something had to be done to force them to comply, because sparks (in general) ignore statute law and only look at compliance with BS7671.

 
The question is: is a dual RCD board compliant, facts are it never has been since its inception! But that's regs for you!😄


I think it can be argued that they CAN comply. Not in all situation. The word minimise is relative to the installation. 

 
Ahh, now there is another myth.

Look up the full technical spec on an Acti9 RCBO, some homework for you.

Yes cost is a valid factor, however, not, in all circumstances.

Some requirements are absolute, even though they are not definitively specified in BS7671, this is one of the reasons for the changes in Amd3, these requirements have been in place for over 10 years now, in statute law, but have not been explicit in BS7671 so sparks have ignored them.

Thus something had to be done to force them to comply, because sparks (in general) ignore statute law and only look at compliance with BS7671.
im just using the acti9 rcbo's as an example i know they have a higher ka rating and comply with 60947, and can have axiliary contacts etc there rated for industrial use

 
I see the acti9 are dp rcbo but could only see them in c type , looks like I've caused a right old debate and I've only just joined lol oh my dayz baby. Ha ha very good luv this place already.

So what are we saying we would need a double pole rcbo on high integrity circuit for the circuit to comply in order to maintain  minimum disruption , inconvenience  on the rest as it's a split load board already. But what then about mixed protection devices in the c/u

 
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Close shanky, but no cigar.

Sorry.

Have another look at the detailed spec, and see why they are not universally suitable (clue).

Ampsayman,

Like I just suggested to shanky, check the spec on the iC60h RCBO.

If you look in the Acti9 brochure it even tells you where they are suitable...

 
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