Any seen a RCBO like this before?

[Raptor0014]

Whilst looking for something else I noticed this on CEF and wondered if they had marketed it wrong and it was infact a RCCB and not a RCBO.

63A Double Pole 2 Module B Curve 10kA 30mA Type A Mini RCBO

Compact modular design

www.cef.co.uk

But looking at the data sheet it appears it is indeed a RCBO. Just curious as it doesn’t appear to have a neutral fly lead. So can only assume it is meant for the incoming supply rather than an individual circuit.

Has anyone used one before?

 

[timhoward]

I don't think I've ever fitted one, but you sometimes find lower rating ones in their own enclosure.
This was a B32 30ma type AC.

I think this was someone's attempt of adding a compliant shower circuit to a bathroom that didn't have bonding, running off a Wylex rewireable board. It got removed when the board was changed.

 

[SparkySy]

Yes I have seen and fitted them before, double pole MCB & RCD all in one, I use them a lot on marinas and caravan sites. Very handy units and until RCBO'S became double pole were one of the few options for double pole isolation without having an MCB and RCD taking up 3 modules!

 

[nicebutdim]

Isn't this the sort of RCBO that would be common in ROI and many parts of continental Europe?

 

[pc1966]

Isn't this the sort of RCBO that would be common in ROI and many parts of continental Europe?

I believe it is.

It also shows the thermal/magnetic trips in both paths which is required in some places without the UK's historical insistence that neutral is really neutral and close to true Earth. Most DP RCBOs you see now in the UK (compact Wylex, Fusebox, etc) are neutral-switching, but they do not sense overload on the N path (though a fault only on N would be tripped by the RCD side of things).

 

[freddo]

Quite often see them in things like caravan hookup points.

 

[MJPD29]

Yes we use a lot of double pole rcbos when working in the south of Ireland

 

[Risteard]

Whilst looking for something else I noticed this on CEF and wondered if they had marketed it wrong and it was infact a RCCB and not a RCBO.

63A Double Pole 2 Module B Curve 10kA 30mA Type A Mini RCBO

Compact modular design

www.cef.co.uk

But looking at the data sheet it appears it is indeed a RCBO. Just curious as it doesn’t appear to have a neutral fly lead. So can only assume it is meant for the incoming supply rather than an individual circuit.

Has anyone used one before?

Double pole switching 2 module RCBOs are very common in Ireland. (Specifically in the south - not in the north where BS 7671 applies.) I actually prefer them to single module devices.

 

[Risteard]

Isn't this the sort of RCBO that would be common in ROI and many parts of continental Europe?

Yes.

 

[Peter - Retired Engineer]

Yes I have seen and fitted them before, double pole MCB & RCD all in one, I use them a lot on marinas and caravan sites. Very handy units and until RCBO'S became double pole were one of the few options for double pole isolation without having an MCB and RCD taking up 3 modules!

Hi, I'm just about to fit an MCG 63A type A, C curve, 2 pole RCBO (Awaiting from CEF) for a new 10mm SWA supply from my meter cabinet. The data sheet says the incoming supply can be either top or bottom. - That's okay, but it does not show which polarity for N and L, just 1,2, 3, 4 on the small picture test circuit. My question is does it matter?

 

[Raptor0014]

Hi, I'm just about to fit an MCG 63A type A, C curve, 2 pole RCBO (Awaiting from CEF) for a new 10mm SWA supply from my meter cabinet. The data sheet says the incoming supply can be either top or bottom. - That's okay, but it does not show which polarity for N and L, just 1,2, 3, 4 on the small picture test circuit. My question is does it matter?

As long as when the contacts are closed you don’t have crossed polarity then no.

So from memory 1-3 & 2-4 correspond.

 

[Peter - Retired Engineer]

As long as when the contacts are closed you don’t have crossed polarity then no.

So from memory 1-3 & 2-4 correspond.

Thank you! That's a relief: I had previously fitted a Type A 2P RCD and that was marked for the N. Wiring in 10mm cable is not quite so easy to swap round. Changing to an RCBO, because I had not thought of an overload trip for the SWA.

 

[DPG]

Thank you! That's a relief: I had previously fitted a Type A 2P RCD and that was marked for the N. Wiring in 10mm cable is not quite so easy to swap round. Changing to an RCBO, because I had not thought of an overload trip for the SWA.

Do you need RCD protection for this SWA feed?

 

[Peter - Retired Engineer]

Do you need RCD protection for this SWA feed?

My design, was to take a feed from the meter cabinet at the back of the house to the front where our cars are parked and supply a Zappi car charger for my EV car. Solar panels are being installed later this year... We are also having electric gates fitted, so needed a supply and I'm having built a new workshop in the front area. (We only moved in 6 months ago). I have put a new meter cabinet on the front decking with a new CU fitted with a SPD, MCB for the Zappi and 2 RCBO's for gates and workshop. It will leave 3 spaces for the solar panels and a Tesla Power Wall. Our main consumer unit is full! The 10mm SWA runs from the back to the front of the house then 6mm SWA for the Zappi (No extra earth required), 4mm SWA for the workshop and 2.5mm SWA for the gates. I have added an isolation switch from the meter, then a Henley block for the new supply and an external 65A Isolation switch. I'm adding the 63A 2P C curve Type A RCBO, (Original Post) between the Henley block and the external isolation switch, more for overload protection than RCD. A bit 'belt and braces'. The Zappi can control the amount of supply from the grid, so as to not overload the main 100A fuse

 

[nicebutdim]

One issue is the lack of discrimination between this upfront RCBO and downstream RCBOs in the new board. Is there a reason why a switchfuse wouldn't provide sufficient protection for the armoured cable?

Will the workshop have its own DB or is everything running directly off that one circuit? If it does have its own DB, can you tell more about it?

 

[LastManOnline]

I don't think I've ever fitted one, but you sometimes find lower rating ones in their own enclosure.
This was a B32 30ma type AC.

View attachment 94848

I have never used any other type of rcbo for the last 25 years except this double pole type.They are a dream to work with. You get D.P. isolation,no fly leads and really easy to install.And guess what??The powers that be have decided to change them for single pole rcbo,s with fly leads?? Give me a break!!

 

[nicebutdim]

I have never used any other type of rcbo for the last 25 years except this double pole type.They are a dream to work with. You get D.P. isolation,no fly leads and really easy to install.And guess what??The powers that be have decided to change them for single pole rcbo,s with fly leads?? Give me a break!!

Ireland is moving to single module RCBOs? In that case you should be able to avail of some 1P+N options, although the majority will have fly leads.

 

[LastManOnline]

Ireland is moving to single module RCBOs?

Its not obligatory to use single module but all the big manufacturers are supplying their new DB,s with single module so it's inevitable it will become the new norm. I think many sparks (like me ) mistakenly assumed they were DP. It's a backward step in my view

 

[nicebutdim]

Its not obligatory to use single module but all the big manufacturers are supplying their new DB,s with single module so it's inevitable it will become the new norm. I think many sparks (like me ) mistakenly assumed they were DP. It's a backward step in my view

While I like the smaller form of UK DBs, it certainly does seem like a step backwards in removing the DP requirement. I guess if sparks insist on single module RCBOs that switch both line & neutral, then wholesalers will stock their shelves accordingly. Question is whether or not people would go with the cheapest option or stick to their guns?

 

[nicebutdim]

Not sure what is stocked by your local wholesalers, but Wylex, Crabtree & CP Fusebox definitely offer a 1P+N option. There are at least a couple of other manufacturers, but names escape me at this time.

 

[Risteard]

Its not obligatory to use single module but all the big manufacturers are supplying their new DB,s with single module so it's inevitable it will become the new norm. I think many sparks (like me ) mistakenly assumed they were DP. It's a backward step in my view

Completely agree. Unfortunately Hager are supplying their domestic DBs with 2 * single mod. RCBOs for the lighting circuits now. I would prefer them to supply with DP busbar and the 2 mod RCBOs. Far superior (and also slightly cheaper).

I've also found the single pole ones unreliable for insulation testing, whereas the 2 mod ones didn't give silly results on this when testing the installation in parallel. I will happily join your crusade for the 2 mod DP RCBOs to be supplied with the DBs.

 

[Raptor0014]

Manufacturers are going double pole RCBO now. Eg I use Fusebox mainly for customers and their Mini single module RCBOs are double pole.

 

[LastManOnline]

I've also found the single pole ones unreliable for insulation testing, whereas the 2 mod ones didn't give silly results on this when testing the installation in parallel.

I,ve had this issue as well. I, m assuming it's to do with the electronics in the rcbo.? Had to carry out testing for an install carried out by a UK company and in order to obtain accurate results had to disconnect the rcbo, s.It was a real time waster.
Two days ago I rang Hagar about their new approach with single mod, s.

 

[nicebutdim]

Two days ago I rang Hagar about their new approach with single mod, s.

Did they disclose anything of interest about future products?

 

[LastManOnline]

Did they disclose anything of interest about future products?

No. Just said the new single mod rcbo does, nt break the neutral. No explanation given as to why not

 

[nicebutdim]

No. Just said the new single mod rcbo does, nt break the neutral. No explanation given as to why not

It's a product they have readily available as it has long been used in the UK. Perhaps they'll develop a 1P+N version if competing products start to increase UK market share or if sparks in IE demand it.

 

[pc1966]

I wonder if this is a "UK/ROI centric" move by Hager, based on typically TN supply, but they still do DP RCBO for EU as typically TT supply?

It really is disappointing that practically nobody does a 1 module double busbar system to avoid the flying leads, and only a few do 1-module neutral-switching RCBO (though I suspect that Fusebox/Wylex/Crabtree might be a significant portion of UK domestic RCBO installations and they do SP+N switching).

 

[Jim_e_Jib]

I wonder if this is a "UK/ROI centric" move by Hager, based on typically TN supply, but they still do DP RCBO for EU as typically TT supply?

It really is disappointing that practically nobody does a 1 module double busbar system to avoid the flying leads, and only a few do 1-module neutral-switching RCBO (though I suspect that Fusebox/Wylex/Crabtree might be a significant portion of UK domestic RCBO installations and they do SP+N switching).

Do SBS have a patent, or some other rights, over the dual busbar system that make it harder for others to implement in the UK?

 

[pc1966]

Do SBS have a patent, or some other rights, over the dual busbar system that make it harder for others to implement in the UK?

I have no idea. I always assumed it was simply that folks wanted RCBO to fit existing CU and nobody actually started from the sensible point of L & N busbars.

Same issues for TPN boards of course, though I have been told that Schneider do a neutral bus but don't know how that works in practice as never seen/played with one.

 

[LastManOnline]

I wonder if this is a "UK/ROI centric" move by Hager, based on typically TN supply, but they still do DP RCBO for EU as typically TT supply?

I posted a thread here locally 2 days ago asking Irish sparks how they felt about the new single module rcbo,s that don t break the neutral. The response is disbelief.It would appear the both regulators and rcbo manufacturers have decided to not publicise this developement.Lets see how things develope

 

[pc1966]

I posted a thread here locally 2 days ago asking Irish sparks how they felt about the new single module rcbo,s that don t break the neutral. The response is disbelief.It would appear the both regulators and rcbo manufacturers have decided to not publicise this developement.Lets see how things develope

I would have to check, but I think the UK regs for TT require DP switching.

Now if you have a 100mA DP RCCB as incomer then some 30mA RCBO for shock protection you get most of that, but personally I feel it should be DP anyway, not just for the risk of a high-N voltage under fault conditions, but also so you get the desired selectivity between RCBO and any up-front RCCB.

 

[westward10]

For ADS on a TT system there is no requirement to switch the neutral, for isolation however all live conductors must be switched.

 

[pc1966]

For ADS on a TT system there is no requirement to switch the neutral, for isolation however all live conductors must be switched.

Thanks for that!

I might have been thinking of the caravan case which (again from flaky memory) have to be DP.

 

[nicebutdim]

I posted a thread here locally 2 days ago asking Irish sparks how they felt about the new single module rcbo,s that don t break the neutral. The response is disbelief.It would appear the both regulators and rcbo manufacturers have decided to not publicise this developement.Lets see how things develope

I hope you highlighted to them the manufacturers who provide single module options for isolating both conductors. Hagar seem to be a very popular brand, both in the UK and IE, but more than once I've found myself looking at their products and asking how this came to be the case.

I note that SBS have since been mentioned in this thread. They're another brand offering 1P+N RCBOs and their dual busbar means no neutral flylead.

 

[Peter - Retired Engineer]

One issue is the lack of discrimination between this upfront RCBO and downstream RCBOs in the new board. Is there a reason why a switchfuse wouldn't provide sufficient protection for the armoured cable?

Will the workshop have its own DB or is everything running directly off that one circuit? If it does have its own DB, can you tell more about it?

Hi, A bit of a delay in replying: Our electric 1/2 AGA 60, arrived a day early!
I agree with you that I'm not sure how any discrimination between the inline RCBO's will work. The one I have fitted today (As in the original post) is a 'C' curve, so hopefully will not cause any nuisance trips and the electric gates and workshop 'B' curve RCBO's will work on their own... I have just connected the EV up to the Zappi (protected just by a 32A MCB) - that's working fine.
As to a 'switchfuse', that would have been the simplest idea and bad planning on my part. I had fitted a 65A Isolation external switch, (just outside of the meter cabinet), but forgot about any overload protection. So I'm hoping everything is covered now.
My workshop when built (Builders did not turn up today), I will add another consumer unit inside with AFDD (18th Amendment 2 - wood construction), a lighting circuit and 2 radial circuits for the sockets.
Thanks for your professional comments.

 

[nicebutdim]

The issue of discrimination will not be affected by the different trip curves, as they relate to overload protection, and it will be pot luck as to which trips in the even of any fault involving imbalance between line and neutral. As the garage board is also to be populated with RCBOs, this would add a third possibility in the event of such a trip - not an ideal situation from the perspective of design or practicality.

 

[Peter - Retired Engineer]

The issue of discrimination will not be affected by the different trip curves, as they relate to overload protection, and it will be pot luck as to which trips in the even of any fault involving imbalance between line and neutral. As the garage board is also to be populated with RCBOs, this would add a third possibility in the event of such a trip - not an ideal situation from the perspective of design or practicality.

Thanks, I'll have to think about it before progressing any further. Will probably be a month before the workshop is built and ready for electrics... It might be easier to swap the first RCBO for a switchfuse...

 

[DPG]

Thanks, I'll have to think about it before progressing any further. Will probably be a month before the workshop is built and ready for electrics... It might be easier to swap the first RCBO for a switchfuse...

That sounds like a better idea to me.

Out of interest, what make of AFDD are you going for, and how much are they each?

 

[Raptor0014]

That sounds like a better idea to me.

Out of interest, what make of AFDD are you going for, and how much are they each?

Cheapest ones I’ve found I can get so far are Fusebox at £106.92 inc VAT

Had a customer last week asking for a quote for a full AFDD board which had 15 circuits.

Soon changed his mind when I said that’s £1600 in circuit protection before we even start with the rest of the materials, labour, testing, certification etc.

 

[pc1966]

Thanks, I'll have to think about it before progressing any further. Will probably be a month before the workshop is built and ready for electrics... It might be easier to swap the first RCBO for a switchfuse...

If you want reasonable selectivity that is the way to go, at least where the sub-main is in SWA so has no need for "30mA additional protection" itself.

Generally I would push the sub-main's supply fuse as high as the sub-main end of cable Zs will allow, but ideally still two steps down from the DNO fuse so it has selectivity with that. (e.g. DNO = 100A then 63A, or DNO = 80A then 50A should have total selectivity with it).

Your high-current selectivity between fuse and RCBO will depend on type and make, etc. For Hager their commercial distribution catalogue has handy tables of selectivity between BS88 fuse & MCB, MCB & MCB, etc. As an exercise, for 50A fuse and Hager 32A B-curve RCBO the selectivity limit is 1.1kA, so faults in the garage below that current ought only to trip the RCBO.

Of course, faults off a 13A fused plug or FCU will be totally selective with any supply fuse of 32A or above.

If you plan this as a workshop then supply selectivity is a bit more of a concern as a fault taking out the lights as well is a real danger. You might also want to put in some emergency lighting just in case (even for mains supply failure) so you are not plunged in to darkness with tools still spinning, etc. You can buy baton-style LED strip lights with battery back-up built in, that is a simple options.

 

[pc1966]

Cheapest ones I’ve found I can get so far are Fusebox at £106.92 inc VAT

Had a customer last week asking for a quote for a full AFDD board which had 15 circuits.

Soon changed his mind when I said that’s £1600 in circuit protection before we even start with the rest of the materials, labour, testing, certification etc.

Yes, quite eye-watering for now!

If concerned, I would probably look at 32A AFDD just on a couple of RFC for the sockets, rather like amendment 2 suggests (I think, not got it yet!), rather than all circuits.

 

[Raptor0014]

Yes, quite eye-watering for now!

If concerned, I would probably look at 32A AFDD just on a couple of RFC for the sockets, rather like amendment 2 suggests (I think, not got it yet!), rather than all circuits.

That’s what I suggested. Stick to the sockets only and at a push the shower, cooker and planned EV charger as they’re quite high loads.

But they decided on just having an all up RCBO board given it saved them a good chunk of ££’s

 

[pc1966]

Generally I would push the sub-main's supply fuse as high as the sub-main end of cable Zs will allow, but ideally still two steps down from the DNO fuse so it has selectivity with that. (e.g. DNO = 100A then 63A, or DNO = 80A then 50A should have total selectivity with it).

Just to add that obviously the sub-main has to be overload protected as well.

If the supply fuse is too high for that (i.e. chosen for only fault protection and good selectivity) then you should make sure the sum of MCB/RCBO fed off the sub-main provides such an overall limit.

For a garage/workshop you might only be talking 6A circuit for lights (fixed load, probably 0.5A these LED days) and something like 20A-32A for socket outlets. So if the sub-main has a CCC of, say, 40A installed, then 2*20A radials or 32A RFC would not overload it, etc.

 

[Peter - Retired Engineer]

That sounds like a better idea to me.

Out of interest, what make of AFDD are you going for, and how much are they each?

Hi again,
I have been into CEF and they don't have a custom made consumer unit with an AFDD already 'plumbed' (sorry rude word!) in yet as they do for SPD - Just looked at the price for an AFDD - £130!!, never mind the CU! I can see why you asked now...

 

[nicebutdim]

It's likely that AFDD prices will start to reduce as more manufacturers introduce them to their ranges, but dramatic price reductions will likely only happen if they are mandated at some point in the future and production ramps up significantly.

 

[Mike Johnson]

The problem with dual module RCBO's is the size of UK boards, soon run out of room on a decent size domestic installation, but agree that going back to fly leads is a retrograde step, how about the white earth lead as well.

FYI In Europe the dual module RCD's and MCB's have the incoming across the top with off set terminals to allow horizontal bus bars, on the multi row boards there are vertical bus bars also available to power the RDC for each row, even for three phase.

Or if you want to use a non offset dual RCD/MCB combination there is this available: A9XPH224 | Schneider Electric Acti 9 2 Phase Busbar, 415V ac, 18mm Pitch | RS Components - https://uk.rs-online.com/web/p/busbars/7762724

 

[DPG]

Hi again,
I have been into CEF and they don't have a custom made consumer unit with an AFDD already 'plumbed' (sorry rude word!) in yet as they do for SPD - Just looked at the price for an AFDD - £130!!, never mind the CU! I can see why you asked now...

Indeed, and don't forget they are per circuit rather than one per consumer unit like SPDs.

 

[pc1966]

Indeed, and don't forget they are per circuit rather than one per consumer unit like SPDs.

Yes, I think we will start to see "one RFC for the house and one RFC for the kitchen" becoming the norm!

Unless the prices really do drop to RCBO like levels, which remains to be seen. Mind you, I have seem them come down from £120+VAT to £99+VAT so only a couple more years...

 

[Mike Johnson]

Indeed, and don't forget they are per circuit rather than one per consumer unit like SPDs.

And also don't forget they don't work?

 

[pc1966]

And also don't forget they don't work?

And (to my knowledge) not testable for the arc-part on any MFT.