New Consumer Unit, which one?

[yellowplum]

I have been looking at various options as we have purchased a new induction hob. Currently we have an old GE Series E unit (1989 13th Edition) that has one spare slot for an RCBO. Having enquired it seems that I am looking at around £25 for a new RCBO for the hob and possibly a second if we decide to install new plugs in another room. Hence my theory that it might be prudent to upgrade the CU to a new one.

I was today offered two wylex boxed NHRS10SSLHI and NHRS7504, I wondered which is better. I was told the latter has a time delay (which I am not sure what is its benefit, if one exists). Other than that I was hoping someone could shed some light and see what the thought process was.

Can someone help?

 

[nickblake]

im asuming that you are not a qualified electrician judging by what you have said , if you are please accept my appologies for assuming your not ,Firstly wylex were subject to a product recall 2009 /10 so the MCB's should be checked , 1989 the regs were 15th edition if you are to replace a CDU these days you can do it either of 2 ways one a CDU with all RCBO protection or a dual RCD board or the same but high integrety (with some spaces for RCBO's ) when this type of work is carried out full isolatio of the installation should be made and full testing carried out and an IEC issued also this work comes under Part P of the building regulations so it must be notified , the consumer units you have listed im not familiar with although i do use wylex

 

[yellowplum]

im asuming that you are not a qualified electrician judging by what you have said , if you are please accept my appologies for assuming your not ,Firstly wylex were subject to a product recall 2009 /10 so the MCB's should be checked , 1989 the regs were 15th edition if you are to replace a CDU these days you can do it either of 2 ways one a CDU with all RCBO protection or a dual RCD board or the same but high integrety (with some spaces for RCBO's ) when this type of work is carried out full isolatio of the installation should be made and full testing carried out and an IEC issued also this work comes under Part P of the building regulations so it must be notified , the consumer units you have listed im not familiar with although i do use wylex

No I am not qualified, just read too much...I have had 3 electricians look at the work involved but they have struggled to find a suitable RCBO to install into the GE unit. So I have tried to look myself and see if I can find one. Meteor claim that one of theirs will fit, otherwise it is a GE RCBO (they have been quoting silly prices £52.49+vat).

So the question is do I risk a Meteor RCBO for £9.50 and see if it will fit (unknown) or do I change the entire consumer unit and be done with it.

Every electrician recommended if I do go down the change route I should opt for a split loading board and 5+5 should be sufficient.

The first Wylex I was offered was, NHISS10SL 10 Way Dual RCD Flexible unit with 100A main switch & 2x 30mA RCD=5, RCD=5 Total=10 at £48.99+vat plus £2 for each MCB

The second was NHRS7504 12 Way Unit with 100A switch & 80A 30mA RCD, Switch=5, RCD=7 Total=12 £37.49+VAT

However my understanding is that the second is not Dual RCD only one side has RCD protection of only 7, so RCBOs would have to be used on the other side rendering it more expensive to use.

 

[telectrix]

the dual rcd board is better for you, but have a look at BG ( British General ) they do a fully loaded dual rcd (and hi integrity) board for around £60. .the hi integrity means you have 2 banks on 2 rcd's and provision for non rcd or rcbo's as well.

 

[yellowplum]

Thanks for the reply, what would the second one be used for? Would you have to buy RCBOs to use the other half of it or just one RCD to convert that side to RCD protection?

 

[nickblake]

ITs a dual RCD so what you do is split the Circuits between the 2 rcd's the unprotected side is for RCBO's these you would use for say the garage smoke detectors and maybe a freezer

 

[yellowplum]

Just called Wylex to clarify, and yes you would have to install RCBOs on one side of the unit. The question is does it offer greater flexibility and protection going down the route of MCBs on one side with RCD protection and individual RCBOs on the other side?

Or is it just better to stick with a Split RCD protected unit installing MCBs on both sides?

 

[malcolmsanford]

All 3 electricians have given you sound advice by upgrading your existing CU you will leave the installation in a safer condition, ie having RCd protection.

Of course if I were one of those electricians I would always offer you differing avenues, and another would be to henley block your main tails from the meter to the existing CU. This then would give you a set of cables to feed the existing CU as it is now, and another set of cables to feed a single RCBO for your induction hob circuit.

Depending on your existing board and it's rating you could also remove the cooker circuit from the protection device, use this protection device to again feed a small single enclosure with a RCBO and then reconnect the cooker circuit into this.

Both the above ways would be a lot cheaper than the changing of the entire board, but as I can not assess your installation it would be wrong to ask why these 3 guys have not suggested these alternatives.

 

[yellowplum]

All 3 electricians have given you sound advice by upgrading your existing CU you will leave the installation in a safer condition, ie having RCd protection.

Of course if I were one of those electricians I would always offer you differing avenues, and another would be to henley block your main tails from the meter to the existing CU. This then would give you a set of cables to feed the existing CU as it is now, and another set of cables to feed a single RCBO for your induction hob circuit.

Depending on your existing board and it's rating you could also remove the cooker circuit from the protection device, use this protection device to again feed a small single enclosure with a RCBO and then reconnect the cooker circuit into this.

Both the above ways would be a lot cheaper than the changing of the entire board, but as I can not assess your installation it would be wrong to ask why these 3 guys have not suggested these alternatives.

It was thought about, the issue is that the board only has spare capacity for one MCB/RCBO currently. So I need a new RCBO for the cooker and a new one for the plugs that I am adding. RCBOs for the GE unit are expensive (Cheapest is around £30 each). With no prospect of expansion should I require it at a later date.

Yes I agree your option or just adding two RCBOs would be the cheapest option in the short term, however a new box isn't that much more expensive. So in essence I am only really looking at a cost of the labour which is a difference of half a day (so they have all quoted).

Hence why I am leaning towards replacement box...

My question regarding the Wylex boxes is in relation to having the split load protected by two RCDs and just buying MCBS or having only one side protected by a single RCD and having RCBOs on the other side. Wylex suggested that the pro of the latter is that if anything goes only the individual RCBO will require examination and the rest will just function, whereas if an MCB goes then the RCD will also trip meaning everything on that side of the board will not be usable?

Was this information correct?
Which route would you go down of the two Wylex options (not that I am settling on wylex I am just looking at the pros and cons of each of the options and wanted an unbiased opinion on them)

 

[londonlec]

Id just buy a £50 RCBO and be done with it.

 

[malcolmsanford]

The information you got from Wylex is correct. If you have a split RCD board then any fault on any circuit that is protected by the single RCD will trip and therfore take out a combination of circuits.

If you utilised single RCBO's then if there was a fault on your cooker only the cooker RCBO will trip.

I can only say this I changed my brothers board 3 years ago from a BS 3036 re-wirable CU, a split board then was approx 110 pounds for a 12 way board, as he had 9 circuits in is house, I fitted a CU with 9 RCBO's in it which came to nearly 300 pounds, so from this I think you can see I'm in favour of the RCBO's