Basic bathroom question...

[polarity]

Hi All

As a reasonably competent DIY'er (with some professional past experience) I am wiring up a new en-suite bathroom (presently a WC) in our 1960's bungalow.

I will arrange to have the design/installation OK'd and tested by an electrician and building control will want to double check. However as this seems like a really friendly forum I would like to check what I am proposing to do is best practice.

At the moment the CU (which was updated about 10years ago) has 2 RCDs running 2 ring mains directly, and the lighting etc. on MCBs coming directly off the mainswitch. The new bathroom is on the other side of the wall to the CU. There is a spur off one of the ring mains running a 2kw heater/light/fan unit in the WC. All the WC lights were on one of the 6A MCBs.

To install new:

Heated Towel rail with electric element

3 x individually switched lights (switches external to bathroom)

Extraction fan

Razor Socket

My proposal is to install an additional 32A RCD in the CU (all there is room for) and wire the existing lighting 6A MCB to it rather than directly off the bar from the main switch as it is at the moment.

From this I will take it to 4 x J804 JB's mounted close to the CU to handle the 3 light loops, wire the new extraction fan to the same loop as one of the lights and take the razor socket directly from the MCB. All with 1mm2 cable (this is as per spec for the small extract fan).

I will feed the towel rail from the existing 2.5mm2 ring main spur with a loop to an external switch (the wife hates pull cords!) - this is an inaccessible JB in the overhead so I will use a maint free box.

I did consider a single distribution box for the lighting loops etc but I have the JBs and they are easier to install and follow as they will all be mounted on a board - though probably over-kill. Pic attached to explain I hope!

Any feedback and things to watch out for regards regs gratefully received.

Thanks !

 

[Evans Electric]

Sounds good to me ,Polarity. You will need an isolator for the fan, which I presume is triggered by the light switch and has overrun. Either 3pole switch or a spur in the lighting feed. Everything in a bathroom should be via RCD , recessed fittings choose fire rated. Looking at your drawing I presume the ring mains are connected to an MCB ( you show them connected to an RCD)

Deke

 

[Apache]

You lost me until I looked at the diagram - most helpful

You don't want a 32A RCD protecting 1mm cable, nor do you need one. Do you mean a 30mA RCD? I'm a little confused?

What make is your CU? Are you familiar with an RCBO - a combined MCB/RCD? A 6A RCBO may do the job nicely.

You want a tripple pole isolator for the fan!

You could take the feed from the CU to both the lights and the shaver socket, save a bit of wire.

I'm sure what you are proposing would work!

I will arrange to have the design/installation OK'd and tested by an electrician and building control will want to double check.

The work is notifiable and you can inform BCO who will inspect it and issue a completion notice or work with a spark and use his sheme, but as things stand a spark can't sign off your work.



One of the proper sparks has probably replied whilst I waffle..................

 

[Evans Electric]

You waffle,.... never !!

 

[Apache]

You waffle,.... never !!

My prediction was correct that a 'proper spark' would have got there first!

 

[polarity]

Sounds good to me ,Polarity. You will need an isolator for the fan, which I presume is triggered by the light switch and has overrun. Either 3pole switch or a spur in the lighting feed. Everything in a bathroom should be via RCD , recessed fittings choose fire rated. Looking at your drawing I presume the ring mains are connected to an MCB ( you show them connected to an RCD) Deke

Hi Deke

Yep, as per diagram the fan is switched by the same loop as the main light (80w light), no seperate isolator though - do I need one? - no overrun as there is an opening window.

No, the ring mains are connected directly to RCDs, no MCB's involved, hence assuming that it was Ok to run the towel rail off it.

Thanks !

 

[Apache]

Hi DekeYep, as per diagram the fan is switched by the same loop as the main light (80w light), no seperate isolator though - do I need one? - no overrun as there is an opening window.

No, the ring mains are connected directly to RCDs, no MCB's involved, hence assuming that it was Ok to run the towel rail off it.

Thanks !

Can you take a picture of your consumer unit?

You sure these RCD's are not RCBO's? If there's no MCB there is no overload protection

 

[Apache]

Yes you need an isolator:

http://www.tlc-direct.co.uk/Main_Index/Wiring_Accessories_Menu_Index/Ultimate_Index/Ultimate_Fan_Switch/index.html

 

[polarity]

...

You don't want a 32A RCD protecting 1mm cable, nor do you need one. Do you mean a 30mA RCD? I'm a little confused?

What make is your CU? Are you familiar with an RCBO - a combined MCB/RCD? A 6A RCBO may do the job nicely.

You want a tripple pole isolator for the fan!

You could take the feed from the CU to both the lights and the shaver socket, save a bit of wire.

I'm sure what you are proposing would work!

The work is notifiable and you can inform BCO who will inspect it and issue a completion notice or work with a spark and use his sheme, but as things stand a spark can't sign off your work. ...

Hi

Thanks for the feedback..

The 32A RCD feeds via a 6A MCB - 32A seems to be the smallest RCD commonly available.

The CU is a MEM "Memera 2000".

An RCBO is a great idea, I have only seen them double height which I am not sure will fit, double width like an RCD is no problem so I will have a google...

If I take the feed to the shaver socket from the lights then the shaver socket would only work with the light turned on - not good for the rechargeable electric toothbrush!

Re building control:

(B) Where work is to be undertaken by a person not registered on a government approved competent persons scheme, but BS7671 certificates will be provided by a competent electrician confirming design, installation, inspection and testing on completion of the works.

This costs

 

[wozz]

the mem rcbos will fit that board, just hope it is neat in there!

 

[Apache]

If I take the feed to the shaver socket from the lights then the shaver socket would only work with the light turned on - not good for the rechargeable electric toothbrush!

I meant take a permanent live when you run the the cable for the lighting - you'd need an extra cable in the first JB! I didn't mean so it only worked when the light was on.

RCBO's do exist for your CU http://cgi.ebay.co.uk/MEM-DELTA-EATON-61MCR-6A-RCBO-RCD-BRAND-NEW-BOXED_W0QQitemZ220452233901QQcmdZViewItemQQptZUK_BOI_CircuitBreakers_RL?hash=item3353fa22ad&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1688|293%3A1|294%3A50#ebayphotohosting

 

[wozz]

youve gone back too far with RCBO pache. Thats for a previous MEM board.

 

[Apache]

youve gone back too far with RCBO pache. Thats for a previous MEM board.

sorry Blushing

meant it more as an example!

 

[polarity]

Yes you need an isolator:http://www.tlc-direct.co.uk/Main_Index/Wiring_Accessories_Menu_Index/Ultimate_Index/Ultimate_Fan_Switch/index.html

Thanks guys - that is exactly the sort of info I was looking for - I did not know I needed one.

Do I mount this in the bathroom out of Zone 2 to just isolate the fan?

Cheers !

 

[Apache]

Thanks guys - that is exactly the sort of info I was looking for - I did not know I needed one.Do I mount this in the bathroom out of Zone 2 to just isolate the fan?

Cheers !

out of zone 2, often mounted on the ceiling either inside or outside the bathroom door. Would allow you to work on the extractor with the light on (good if breaks on a cold winter evening) and allows you to use the light if the fan becomes faulty.

 

[polarity]

Can you take a picture of your consumer unit?You sure these RCD's are not RCBO's? If there's no MCB there is no overload protection

Yep, having just opened it up a few days ago (not been in long), I was thinking about upgrading it to a 17th edition box. As you can see it is reasonably neat, I moved everything up one space to creat the double gap.

BTW, The cooker,hob and immersion heaters (x 2) are in 2 other seperate CU boxes (MCB's only) along with the UFH, each one of the 2 other boxes runs on an "off peak timer" - each box is on a different phase and has its own meter.... I'll come back to that one as according to the labels on the T.Stats we have 380v UFH....

 

[Apache]

Your rings are on RCBO's not RCD's!



It's another one of them you need 6A (overload protection) 30mA (trip with the RCD part)

 

[polarity]

Your rings are on RCBO's not RCD's!

It's another one of them you need 6A (overload protection) 30mA (trip with the RCD part)

Doh ! Blushing ...Of course hence the 32A bit... sorry, terminology confusion, after so long in US boats I have only just got past calling an RCD a GFI!

RCBO like this ?... http://www.dustonelectrical.co.uk/products/Power+Distribution/Three+Phase+Distribution/MEM+RCBO%27s+/MEM+MCH106R30+6A+30mA+RCBO/3855477465

 

[Apache]

Doh ! Blushing ...Of course hence the 32A bit... sorry, terminology confusion, after so long in US boats I have only just got past calling an RCD a GFI! RCBO like this ?... http://www.dustonelectrical.co.uk/products/Power+Distribution/Three+Phase+Distribution/MEM+RCBO%27s+/MEM+MCH106R30+6A+30mA+RCBO/3855477465

I doubt it. Look for one like the ones you have!

(I'm not a spark, just a vet that hangs around Blushing)

 

[polarity]

I doubt it. Look for one like the ones you have! (I'm not a spark, just a vet that hangs around Blushing)

hmm time to upgrade my avatar then...

Thought as a MEM RCBO it might work, will keep looking.

new enlightened diagram ...