Should I fit an RCBO or a MCB?

[DocScrewdriver]

Hi,
just recently refitted bathroom and fitted a new 9kw Triton shower with 10mm twin & earth and a 50amp Crawford pull switch (nicely designed to help fit bulky 10mm twin & earth cable)
I then bought a Hager RCBO (CU is Hager unit) but noticed it was taller than the existing MCB's plus there is a thin 'flying earth wire built in.
Can I use the taller RCBO or should I just fit a 45 amp MCB since the CU is split anyway into zones protected by RCD's? (House was built in '99 and CU is of same age)

Cheers
Andrew

 

[EFLImpudence]

You don't need an RCBO if all circuits are protected by another RCD already.

 

[Taylortwocities]

I'm guessing you did this as a DIY project?
New circuits and most electrical work in bathrooms are notifiable to the local authority. What are you planning to do about that?

 

[DocScrewdriver]

Yes - it is DIY (have followed current regs up until now) and will be notified. Trouble is I'd already bought an RCBO last year which is still wrapped up unused. I was trying to plan ahead. The plan was to use same make of component as the CU, ie Hager.

 

[EFLImpudence]

The plan was to use same make of component as the CU, ie Hager.

Don't follow the logic - you should do that.

You could wire it separately or

for £3 ish get a 40A MCB which will be satisfactory (don't think Hager do 45A).

 

[DocScrewdriver]

Reason I got an RCBO was after reading a similar question on another forum run by a certain large DIY and trade retailer. I should have gone to this forum first.

 

[JohnW2]

Yes - it is DIY (have followed current regs up until now) and will be notified.

The problem with that is that if you were going to notify yourself (and pay the £££ fee), you would have to have done so before the work started.

Kind Regards, John

 

[Iggifer]

You only really need an RCBO when there aren't enough RCD protected ways available. There's absolutely no point putting it in a dual RCD board. Put it on eBay

 

[DocScrewdriver]

The bathroom was basically removing old suite and fitting new bath, basin and wc using existing pipes. The electric shower cable isn't connected up either end ie not shower or CU but has been fed along a route that enables the electric shower to be connected by sparky.

 

[sparkwright]

You must be certain the part of the consumer unit you wish to add the MCB together IS protected by an RCD.

I wouldn't expect a consumer unit from 1999 to be dual RCD.

I would expect one side of the consumer unit to be RCD protected, the other side unprotected.

You could easily fit your RCBO to the UNprotected side. This is where RCBOs are designed to go, as it will then provide that circuit with RCD protection.

Adding an RCBO to the protected side isn't a particularly good way of doing things, and would go for an MCB here.

 

[DocScrewdriver]

Cheers for the info and heads up. I won't proceed until all this notifiable stuff is out the way.

 

[ban-all-sheds]

Yes - it is DIY (have followed current regs up until now) and will be notified.

Notification has to take place before you start, because as part of it you have to tell them how you'll ensure compliance with Part P, and they have to agree.

 

[JohnW2]

Yes - it is DIY (have followed current regs up until now) and will be notified.

Notification has to take place before you start, because as part of it you have to tell them how you'll ensure compliance with Part P, and they have to agree.

Indeed, but I made that point a couple of hours ago...

The problem with that is that if you were going to notify yourself (and pay the £££ fee), you would have to have done so before the work started.

Kind Regards, John

 

[PrenticeBoyofDerry]

Sounds like the OP has not done enough research and is under-prepared, ill-informed and undereducated to proceed any further with this task! If (big if) an electrician had been pre-arranged to make the final connections and tests, they would have informed the OP of what was required.

The circuit needs to be notified and approved prior to starting the work, cables and protective device need to be sized and selected correctly, cables routed within permitted zones, equipment selected suitable for the environment and IP ratings need to be compliant to BS7671.

Then before energising the circuit a series of tests must take place to confirm it is safe to energise, then on energising, further test are required to confirm the circuit is safe to be commissioned and go in to service, these results must then be documented in an electrical installation certificate.

Regrettably sounds like some/most of this has not and possibly will not be adhered to.

 

[ban-all-sheds]

But...

have followed current regs up until now

Is the OP telling us things which are not true?