Shower CU and split Tails Question

[MasterAbacus]

Hi guys, Just a quick one....Honest...

The picture attached is what a friend has been given for a shower CU.

I'm really being nosey, but could someone explain something here...

The Current set up already has tails to a black splitter box (cant remember what their technical term is), one set off to old CU and another set heading towards the new CU for shower. (potentially)

The shower is a 9.5kw mira, running on a 10mm cable.

The incoming meter tails don't seem quite 25mm (I could be wrong here tho) the new tails that are ready to be installed are 25mm Double insulated, so maybe the older ones are 25mm..

as you can see from the picture the setup is as follow...

RC263/030 63A RCBO??? (Is it)?
MC140B C40 MCB?

the rail these sit on is very flimsy, and I'm pretty sure isisn't buzz bar setup.

The Nuneutrals obs coconnections the cable to block is in place.
ImI'mot sure that the 10mm shower cable will fit into just one of the coconnectorsho, will this ahhaveo be split between two???

Also the live side of what I'm calling the RCBO seems to have a bridge bar to the MCB, I aassumethe shower feed live will cconnectto the top of the MCB, thus the ccircuitwill have RCBO pprotectionvia this link bar?

Again the Earth cconnectorlooks very small, and my friend has been told that a couple of 4mm earth links from main CU earth block to new CU earth block will be ok for this?

Sounds to me like he got a dodgy sparks in, but id like to make sure i know where I'm coming from before i put in my two peneth..

Look forward to the comments on this one...

Rgds



M.A.

 

[jj4091]

Why be nosey & try & put in your "two penneth" when you don't know what you are talking about, if you are concerned about your friends safety, then pay a professional to come in & check it out for them.P.S. your link doesn't work.



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It does now! M R
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[MasterAbacus]

Why bother posting a reply if your not going to be helpfull....

The link does work if you copy and paste it, i believe they take time to upload...

As for my question and concerns, i know enough, and im always looking to learn more. Hence why i asked the above. If its right then great ill learn, if its wrong and someone advises on how it should be done i learn again.... Hence the reason for a Forum like this etc.......

If one doesnt know, one should ask......

If ones not going to be helpfull one shouldnt stick ones ore in should one...

 

[pcboffinuk]

MA,

Nothing wrong with asking questions if you are unsure in my opinion.

I've corrected your image link

Couple of things I can hopefully clear up...


The picture and your description shows that you have a RCD (RCCD) main switch rather than a RCBO.

The Rail the breakers attach to is purely to secure them, the 'busbar' is what you are calling the 'bridge bar' and does indeed transfer the live to the mcb and thus provide rcd protection.

The live core of the shower cable will connect to the MCB, and the neutral core to the neutral block
.

The earth block in that CU should accept 16mm earths, and really you want a 16mm earth from the main earthing terminal (MET) which may be on the original CU or separate. 2 x 4mm earth cables isn't really the way to go, although it may be compliant if the installer has done all the calculations.

What does the instructions for the shower say about a suitable MCB? 9.5kw at 230V is 41A, so you may well find that a 40A breaker will trip when the shower iis turned on.

When you say incoming meter tails, do you mean the ones to the original CU, or the ones from the supplier cut out to the Henley Block (the name you were struggling for).

what meter tails you MUST have will depend on the rest of the installation, and what the main supplier fuse is rated at - but I doubt you have a major problem there. What is the main switch rated at on the original CU?

I'm sure others will put their oar in

Gavin

 

[MasterAbacus]

Thanks Pcboffinuk.... great start.... at least the pictures up now....lol

Right a couple more questions then following on from your reply...

It says in Instructions RCBo protection should be fitted....
Whats the difference between an RCCD and an RCBO? Do they do same job?

Henley block... thats the name.... nice one...

The Incoming main is fused 100A same as the orig CU. The metertails go from Main to block the split off to orig CU and then soon out to new CU. My concern was the new tails from block to new CU seemd to be bigger then the others.

How about the fitting of the cables to the terminal blocks in the new CU? earth and nutral? will they be ok to be split into two holes/slots and screwed down? Iask this cos they seem rather small to me to fit in the cables...


As for the 40A breaker.... will that trip straight away if its wrong? or only when the shower is turned upto full heat/power?


Many thanks


M.A.

 

[jj4091]

Why bother posting a reply if your not going to be helpfull....

The link does work if you copy and paste it, i believe they take time to upload...

As for my question and concerns, i know enough, and im always looking to learn more. Hence why i asked the above. If its right then great ill learn, if its wrong and someone advises on how it should be done i learn again.... Hence the reason for a Forum like this etc.......

If one doesnt know, one should ask......

If ones not going to be helpfull one shouldnt stick ones ore in should one...

My suggestion was serious & intended to be helpful. Although you are eager to learn, you obviously do not "know enough" especially to be able to criticise a tradesman's work (dodgy sparks). One should not be so far up one's arse that one will not consider all suggestions.

 

[obmitty]

My suggestion was serious & intended to be helpful. Although you are eager to learn, you obviously do not "know enough" especially to be able to criticise a tradesman's work (dodgy sparks). One should not be so far up one's a**e that one will not consider all suggestions.

Whats the point of this forum then? Surely we should all just pay someone who knows?

 

[davelx]

An RCBO combines the functions of an RCD and an MCB, so what you have is fine.

A 40A MCB will not trip on a 41A load. MK type B tech data show a trip time >1hour for loads up to 1.13In = 45A, and 1hr for 1.45In = 58A.

 

[jj4091]

My suggestion was serious & intended to be helpful. Although you are eager to learn, you obviously do not "know enough" especially to be able to criticise a tradesman's work (dodgy sparks). One should not be so far up one's a**e that one will not consider all suggestions.

Whats the point of this forum then? Surely we should all just pay someone who knows?

I was under the impression this forum was to help people do jobs for themselves, not seek help & information that they could use to impress there friends & criticise tradesmen.

 

[MasterAbacus]

at what point did i say I was going to criticise tradesmen. I only said i wanted to find out information before putting in my two penneth....

Thanks for the pointers so far on this guys and gals...

I have a much better understadanding of it now....

Im still not convinced the cables will fit in the connectors, and i cant wait to see how the (Sparks) gets round it....

 

[plugwash]

Thanks Pcboffinuk.... great start.... at least the pictures up now....lol

Right a couple more questions then following on from your reply...

It says in Instructions RCBo protection should be fitted....
Whats the difference between an RCCD and an RCBO? Do they do same job?

a mcb is a combination of a MCB and RCD, you have the two seperate, doesn't really matter either way.

My concern was the new tails from block to new CU seemd to be bigger then the others.

if indeed it it fused at 100A (many houses aren't even though the carrier can take fuses up to 100A) then 16mm cable is borderline and 25mm is good practice. I suspect your original tails are only 16mm and the new ones are 25mm but given that there is unlikely to be a load as big as 100A for any significatn time i really shouldn't worry about it,

How about the fitting of the cables to the terminal blocks in the new CU? earth and nutral? will they be ok to be split into two holes/slots and screwed down? Iask this cos they seem rather small to me to fit in the cables...

the holes really should be big enough to take 10mm cable though

As for the 40A breaker.... will that trip straight away if its wrong? or only when the shower is turned upto full heat/power?


Many thanks


M.A.[/quote]