RCBO Replacement under 18th Edition

[Baga Bones]

Hi,
Complete laymen to the electrical world so need some advice.
We had a complete rewire done in 2016 and as part of this we had an RCBO unit put in. Today we have had an issue where there has been a loose connection and the board needs replacing. This is being done under our house cover but the electrician has advised we won't be having the same sort of board as the 18th edition rules have improved the requirement and therefore we will be having something better that includes mcbs. I don't have a clue about any of this so wanted some advice as to what is correct and what I should be pushing for. I've included a couple of pics of the board if thats any help.
Thanks.
View attachment 44534

 

[Dave OCD]

A lot of manufacturers recommend mixing light and heavy loads along the boards to avoid mutual heating and magnetic effects.

And there's even a tick box in the schedule of inspections for this....

 

[westward10]

And there's even a tick box in the schedule of inspections for this....

Which one, can't be bothered to look.

 

[Dave OCD]

Which one, can't be bothered to look.

I can't be bothered either this time of day but it's in the Consumer Units part of the schedule [EIC and EICR I think], of course it could refer to other things too, such as not not having a single live conductor through a metal hole.

 

[Toneyz]

itusedto be back in the days when old busbars preferred the heavier loads closer to the main switch, but not been considered good practice since pete999 got out of nappies

What! that long ago!!!!!!!!!!!!

 

[Octopus]

Actually the 18th edition mentions that one or more circuits can be protected by a common rcd subject to other applicable regulations such as this new 30% value of the rcd for earth leakage to the shared circuits on the same rcd

I’ve long pondered how we are supposed to calculate this , and how anyone could say a new install doesn’t comply ........is anyone’s guess

 

[Ian1981]

I’ve long pondered how we are supposed to calculate this , and how anyone could say a new install doesn’t comply ........is anyone’s guess

It’s quite interesting how we will deal with circuits that require high integrity earthing such as IT equipment socket outlet circuits and pieces of equipment that exceed 10 mA, as if they are to be on a 30 mA rcd then that’s 9 mA at 30% maximum.
So I guess you can ignore high integrity earthing when installing a ring circuit for IT equipment as your circuit should be designed not to exceed 9 mA unless the rcd is dumped by doing a risk assessment.
Another well thought out regulation change

 

[Dave OCD]

@Sparky Pat ,can you kindly elaborate on what you consider bad spelling in post 41 please ? Just so I can learn from my mistakes.

 

[Wilko]

It’s quite interesting how we will deal with circuits that require high integrity earthing such as IT equipment socket outlet circuits and pieces of equipment that exceed 10 mA, as if they are to be on a 30 mA rcd then that’s 9 mA at 30% maximum.
So I guess you can ignore high integrity earthing when installing a ring circuit for IT equipment as your circuit should be designed not to exceed 9 mA unless the rcd is dumped by doing a risk assessment.
Another well thought out regulation change

Ha - well spotted - must mean there's not quite enough monkeys with typewriters in there yet. Hopefully the next one will turn it into 1/3 say.

 

[MFS Electrical]

Utter crap sounds like he wants to fit a dual RCD board to save a bit of money the setup you have there complies with the 18th edition and sticking in a dual RCD board could potentially cause problems with Selectivity(discrimination) ie a problem on one circuit could wipe out a few instead of just one I suggest you say to your electrician you want an RCBO board installed or find yourself another electrician.
RCBOs already incorporate both an RCD and an MCB for each and every circuit rather than MCBs for every circuit and RCDs protecting a bank of circuits.
To be perfectly honest he sounds like a bit of a chancer.
The only way to improve on the setup you have there is to install Arc Fault Detection Devices AFDDs but this can still be done using RCBOs anything else is just a compromise and not as good as what you already have

 

[Midwest]

Have you seen a board with AFFD's in it, available for the domestic market. Think they are rocking horse pooh at the moment.

 

[MFS Electrical]

Have you seen a board with AFFD's in it, available for the domestic market. Think they are rocking horse pooh at the moment.

Yeah just one though and I’m still not quite sure it’s for sale the rep had 2 one with two AFDDs and two RCDs and 6 MCBs and one with two AFDDs and 6 RCBOs the split board one was bloody massive. He did also say they were working on potentially incorporating AFDDs in with RCBOs but he reckoned that was still a couple of years away. Still annoys me that the regs say give consideration to fitting AFDDs cause if you don’t and there is a fire your gonna be carrying the can and have to justify why you considered them unnecessary we all know they will become mandatory (like RCDs did) in one of the amendments of the 18th so why not just say in black and white Fit them and that way your customer isn’t going to be looking at you like you have horns on your head when you explain that your going to fit AFDDs and everyone else that’s quoted have said Sod it

 

[Pete999]

@Sparky Pat ,can you kindly elaborate on what you consider bad spelling in post 41 please ? Just so I can learn from my mistakes.

I see no spelling mistakes 10 out of 10 Dave

 

[Pete999]

Utter crap sounds like he wants to fit a dual RCD board to save a bit of money the setup you have there complies with the 18th edition and sticking in a dual RCD board could potentially cause problems with Selectivity(discrimination) ie a problem on one circuit could wipe out a few instead of just one I suggest you say to your electrician you want an RCBO board installed or find yourself another electrician.
RCBOs already incorporate both an RCD and an MCB for each and every circuit rather than MCBs for every circuit and RCDs protecting a bank of circuits.
To be perfectly honest he sounds like a bit of a chancer.
The only way to improve on the setup you have there is to install Arc Fault Detection Devices AFDDs but this can still be done using RCBOs anything else is just a compromise and not as good as what you already have

The use of AFDDs is a recommendation, Regulation 537.6, if you have a copy of the New Blue OSG, I suggest you read from page 38 to 43 inclusive, these pages give you a brief overview of the needs of both SPDDs and AFDDs including where when and how they should be installed.

 

[Baddegg]

Yeah just one though and I’m still not quite sure it’s for sale the rep had 2 one with two AFDDs and two RCDs and 6 MCBs and one with two AFDDs and 6 RCBOs the split board one was bloody massive. He did also say they were working on potentially incorporating AFDDs in with RCBOs but he reckoned that was still a couple of years away. Still annoys me that the regs say give consideration to fitting AFDDs cause if you don’t and there is a fire your gonna be carrying the can and have to justify why you considered them unnecessary we all know they will become mandatory (like RCDs did) in one of the amendments of the 18th so why not just say in black and white Fit them and that way your customer isn’t going to be looking at you like you have horns on your head when you explain that your going to fit AFDDs and everyone else that’s quoted have said Sod it

I think once you explain the cost and the fact that they are only a recommendation at this stage,at a domestic level the home owner will say no to fitting them, surely you can then make a note on cert and or invoice that you recommended and customer declined?

 

[Pete999]

I think once you explain the cost and the fact that they are only a recommendation at this stage,at a domestic level the home owner will say no to fitting them, surely you can then make a note on cert and or invoice that you recommended and customer declined?

Or you could say see Reg 537.6

 

[westward10]

Or seeing as at present it is not a domestic suggestion why even bother mentioning them.

 

[suffolkspark]

They dont do them in 3phase do they ?

 

[Pete999]

They dont do them in 3phase do they ?

Don't do what in 3 phase SPDDs?

 

[suffolkspark]

Afdds

 

[Pete999]

Afdds

Don't think so!