3-RCD consumer unit 15 ways or more?

[STEVEROG]

I'm looking for a 3-RCD consumer unit that will provide at least 15 ways, any suggestions would be appreciated.

I did considered an all-RBCO consumer unit which would of course need fewer overall module slots but a little over the top cost wise and many of these seem to be tight on wiring space.

I could run with just 13 ways as I only have 13 circuits but this leaves me no room for expansion. Actually, I could get away with 12 circuits if I put my smoke detectors on a lighting circuit which seems to be a preferred approach by many to provide an indication that the smoke alarm circuit has tripped (you got no lights) but I'm assuming a separate circuit for the smokeys for now.


Anyway, getting off topic.



Thoughts?

Oh BTW... BC informed.

SGR

 

[JohnW2]

I'm looking for a 3-RCD consumer unit that will provide at least 15 ways, any suggestions would be appreciated.... Thoughts?

As a matter of interest, why 3 RCDs?

Kind Regards, John

 

[PrenticeBoyofDerry]

You will find most common CUs only really go up to 22 modules, so 2 for main switch and 6 for RCCBs, will leave you with 14 ways.
But there's always the 2 rowers that go up to about 40 mods in total

 

[AndyPRK]

How about a wylex with 2 rcds and then make up the rest with rcbos.

 

[mfarrow]

Assuming this is a new installation/rewire, Have you considered alternatives to RCD protection where it is not expressly required for socket outlets? Many are cheaper than RCBOs.

 

[ericmark]

You can get stacked consumer units which would allow four RCD's

if that's really what you want.

 

[PrenticeBoyofDerry]

But there's always the 2 rowers that go up to about 40 mods in total

 

[PrenticeBoyofDerry]

You can get stacked consumer units which would allow four RCD's

But there's always the 2 rowers that go up to about 40 mods in total

 

[nickjb]

Do you need 3 rcds? I've just put in a 15 way Wylex. Its in three groups with 2 rcds and you can adjust the number of ways in each group. I've got two rcds each with 5 ways and another 5 non rcd (currently 1 for fridge, 1 for garage with local rcd, an rcbo for an outside socket and two spare)

 

[dhutch]

How about a wylex with 2 rcds and then make up the rest with rcbos.

Do you need 3 rcds? I've just put in a 15 way Wylex. Its in three groups with 2 rcds and you can adjust the number of ways in each group. I've got two rcds each with 5 ways and another 5 non rcd (currently 1 for fridge, 1 for garage with local rcd, an rcbo for an outside socket and two spare)

Would work for me!

 

[AndyPRK]

How about a wylex with 2 rcds and then make up the rest with rcbos.

 

[mfarrow]

Assuming this is a new installation/rewire, Have you considered alternatives to RCD protection where it is not expressly required for socket outlets? Many are cheaper than RCBOs.

 

[JohnW2]

Assuming this is a new installation/rewire, Have you considered alternatives to RCD protection where it is not expressly required for socket outlets? Many are cheaper than RCBOs.

Since you have repeated this suggestion (which I suspect many readers may have found a bit 'cryptic'!) .... I presume you are referring to the use of mechanical (rather than RCD) protection for buried cables. I would argue that, even if you can argue that it is cheaper than RCBOs, it's an awful lot more hassle and, of course, many/most people believe (rightly or wrongly) that RCD protection, per se, is a desirable thing, even when it's not required because of buried cables.

In fact, seeing the way that the regs are going, it wouldn't surprise me if (perhaps with a few exceptions) the day comes before too long when (again, 'rightly or wrongly') there will be a requirement for virtually all final circuits in domestic installations to be RCD-protected - so your 'solution' might find itself 'non-compliant with current regs' before all that long!

Kind Regards, John

 

[STEVEROG]

Hi all,

Thanks for the many and varied suggestions.... plenty of food for thought.

I was leaning towards a 3-RCD solution for a few reasons...

(a) The sum of any leakage currents would be lower per RCD. Of course, in an ideal world the circuits don't have any leakage current but we know this isn't true in practice.

(b) The number of circuits dropped by a fault is less. That's not a huge advantage though in a shift from two to three rcd's

(c) A bit more scope to deal with any nuisance tripping circuits. That said, best practice would be to sort these out!

I'm not keen on running with any non-RCD circuits as although the mechanical protection is acceptable it doesn't address issues with stuff plugged in to the sockets.

I'd considered having outbuildings on a non-rcd circuit and then have an RCD at the outbuilding but this would leave the cable in between the house and outbuilding non-protected except for the mechanical protection.

I think a stacked board is overkill for my application. I'm now warming to the idea of a dual RCD approach and will probably opt for the maximum 22 module board and build to a two-RCD design but would try to get a board that has the terminals in place to shift to a three RCD if I so desire later.

I'll then steal the good idea of having a couple of RCBO's to cover any circuits that might be a bit 'trippy' or don't want 'taken out' by the other circuits.

What the thoughts on the smokey's? on their jack jones or paired up with a frequently used lighting circuit?

SGR

 

[JohnW2]

I was leaning towards a 3-RCD solution for a few reasons...
(a) The sum of any leakage currents would be lower per RCD. Of course, in an ideal world the circuits don't have any leakage current but we know this isn't true in practice.
(b) The number of circuits dropped by a fault is less. That's not a huge advantage though in a shift from two to three rcd's
(c) A bit more scope to deal with any nuisance tripping circuits. That said, best practice would be to sort these out!

All theoretically valid points - but they are ones which everyone faces, and most people seem to be satisfied by just two RCDs (maybe plus an RCBO or two).

I'm not keen on running with any non-RCD circuits as although the mechanical protection is acceptable it doesn't address issues with stuff plugged in to the sockets.

In fact, with few exceptions, RCD protection is required for all domestic sockets - even mfarrow implicitly acknowledged that.

I'd considered having outbuildings on a non-rcd circuit and then have an RCD at the outbuilding but this would leave the cable in between the house and outbuilding non-protected except for the mechanical protection.

I would say that's sensible. Provided you do not have a TT installation, there's no requirement for that cable to be RCD protected. It will obviously be protected by the MCB.

I'll then steal the good idea of having a couple of RCBO's to cover any circuits that might be a bit 'trippy' or don't want 'taken out' by the other circuits.

Fair enough.

What the thoughts on the smokey's? on their jack jones or paired up with a frequently used lighting circuit?

Opinions will vary a little, but I think most people probably favour the latter, for a fairly obvious reasons.

Kind Regards, John