18th Edition Compliant Consumer Unit

[spark 68]

It should be at least SPSN, if not DP which is what I originally said, because leaving a N-E fault present is short sighted in my opinion, which is what the vast majority of RCBOs do.

 

[jamie-spark]

It’s all very well if the circuit requires RCD protection , if it doesn’t as stated above a N-E fault would still go undetected, should we be installing sub main supplies in SWA with rcd protection in case there is a N-E fault. Think of the distription due to discrimination this would inflict

 

[spark 68]

I did not say that all, I suggest you re- read what I actually said,
your last post was pretty much incomprehensible

 

[jamie-spark]

I did not say you said that either , I suggest you re-read my post. What is incomprehensible about it and I will try to elaborate for you.

What you are saying is that all RCBO’s (in your opinion and not “should be “ Double pole . What I am trying putting across ,is why do you feel this should only be limited to RCD protected circuits . N-E faults would go undetected on most other circuits where RCD protection is not required

 

[jamie-spark]

because if you get a N-E fault this will of course trip the up front SP RCBO device, however by being SP will leave the N-E fault still present.
Now if this was a farm or agricultural install this will also trip the front 300mA RCD required for fire protection, with no means of being to isolate the fault, at least a (SPSN) single pole switched Neutral would Isolate the N-E fault.
This should have been designed in from the get go, even for domestic where a SP RCBO still would leave a N-E fault present.

It would be ---- poor design to have a upfront 300mA rcd with a SP rcbo down stream . I totally agree

 

[Electric Magic]

This is ridiculous. Given what is in the Beama guidance why have so few of the other manufacturers bothered changing their products? It is so fricking shoddy that such a big change is introduced, has been in force for two months, and yet suitable products are not available from all manufacturers of units for the domestic market. What a load of boll***s.

 

[Electric Magic]

Duplicate

 

[Midwest]

Correct me if I’m wrong, but up to a couple of years ago there very few availability DP or SPSN RCBO’s about anyway. Recall one the only available ones from that guy who assembled his own CU products, SBS or something like that.

Now we have these new regs, where these manufacturers have been on the panel, are there’s still sparse availability.

Slightly different subject, but same point £205 for a 6A RCBO/AFDD. Really, see a lot of them going in.

 

[mattg4321]

So anyone have any ideas on where we stand if we want to add another circuit to an existing consumer unit.

Presumably if I want to add a 32A MCB to a dual RCD consumer unit with 63A RCCB's (lets say for arguments sake they both have a 32,16 and 6A MCB on), I'm also going to have to persuade the customer that I need to upgrade the RCCB to 100A. That's if its even possible to source one for some of the consumer units of course!

 

[Baddegg]

I read it as the rcd/rccb needs to be equal to or greater than main fuse but diversity can still be applied downstream of them? I am also on some heavy duty painkillers right now.....so could be talking absolute b@&&ocks.....as even with 100a rcd/rccb some consumer total circuits downstream would still be greater than 100a?..........sod it rcbos all the way

 

[Wilko]

I think if the manufacturer specifies the RCD must be equal or greater than the fuse, then that's what needs doing. We used to have leeway with design to ensure the RCD wasn't overloaded, but now we shall do as we are told .

 

[Midwest]

Me thinks this not been though ?

 

[mattg4321]

Is it ever?

They can't even release a book that is years in the making without a load of spelling mistakes and other basic errors.

 

[Midwest]

Me thinks this not been though ?

On iPhone, I wanted to say this not been thought threw Me thinks

 

[Baddegg]

On iPhone, I wanted to say this not been thought threw Me thinks

I understand buzz Midwest....that was no probs

 

[alasdairp]

sorry if this is duplicated - I had trouble posting it.

I only tend to read through the forum once a week. Not to be able to take diversity into account w.r.t. RCD rating is, in my opinion, quite ridiculous. Very few 32A RFCs ever get more than maybe a 3 kW fan heater and a few other low power items running at the same time - say 15A total - so maybe we should be fitting 20A MCBs to RFCs - especially upstairs RFCs. Kitchen and utility circuits usually supply more current, but even then 20A would normally suffice (apart from cooker and shower). Maybe this approach would be better that replacing 20A RCDs with 100A ones? As another previous post said, this requirement undermines the whole issue of diversity.

I strongly suspect that this RCD nonsence (and the AFDD one!) is manufacturer profit driven. Don't forget that "BEAMA is a member association that represents manufacturers of electrical infrastructure products and systems", it is NOT a safety organisation. It represents its manufacturing members and promotes their financial and other interests. It is a manufacturers "friendly society" or club.

The IET seems to have somewhat lost the plot with the buggy and imprecise "recommendations" in the 18th Ed. Maybe they should hand the job over to CIBSE as someone above suggested. I don't know if they would be better, but IET seems to have lost the art of practical electrical common sense.

I despair that red-tape is starting to overwhelm the comon good in an increasingly expensive "throw away and don't attempt to repair" society.

 

[Deleted member 26818]

Next will be 20A for RFCs.

 

[spark 68]

Don't give them any ideas Spin that will be in a future amd

 

[Toneyz]

I get up to the point in the regs with the use of RCD's/RCBO's for sockets to protect against faulty equipment and for the greater risk areas eg bathrooms outdoors swimming pools etc from then onwards the regs are being written to protect the idiots eg metal stud, cables in walls domestic lighting circuits AFPD's not saying that they are bad things. If the installation is designed and constructed using approved materials together with good sound workmanship the extra protection should not be needed the trusted fuses and MCB's served well for many years.

 

[Midwest]

I get up to the point in the regs with the use of RCD's/RCBO's for sockets to protect against faulty equipment and for the greater risk areas eg bathrooms outdoors swimming pools etc from then onwards the regs are being written to protect the idiots eg metal stud, cables in walls domestic lighting circuits AFPD's not saying that they are bad things. If the installation is designed and constructed using approved materials together with good sound workmanship the extra protection should not be needed the trusted fuses and MCB's served well for many years.

Thats ok until the end users get involved, i.e. human beings, then everything goes swivel.