Cloakroom Refit

[swisscheese]

I am having a shower fitted in the down stairs cloak and want to have installed 12v extractor (zone1) and 3 downlighters, one of which will be in in Zone one, I have had quotes on this job, but with significant differences, the obvious one being the need for and extra rcd or not.

As i understand it the work involves cutting into the existing lighting circuit and adding a 3 pole isolator before the transformer, but does this work need an extra RCD installed as well.

Thanks for your help.

 

[ianmacd]

It will need an RCD of 30mA. If the circuit is currently protected by one that passes testing then I can not see why you would need another one.

 

[SPECIAL LOCATION]

Hello SwissCheese, Welcome the the forum...

If it is being done all good and proper in accordance with latests regs;

Rooms containing a bath or shower:

Wiring regs section 701

Page 166 of BS7671 (wiring regs)

Regulation 701.411.3.3

says:

Additional protection shall be provided for all circuits of the location, by the use of one or more RCD's having the characteristics specified in Regulation 415.1.1 (thats a 30ma RCD)

so YES your wiring alterations should have an RCD fitted.

Also this work would be within the scope of Part-P building regulations,

You will want to check your electrician will be notifying the work on your behalf and ensuring you get a

"Building Regs compliance certificate."

HTH

 

[Lurch]

If the lights and fan are SELV and the 230V is all outside the bathroom does it need an RCD?

 

[SPECIAL LOCATION]

If the lights and fan are SELV and the 230V is all outside the bathroom does it need an RCD?

I know what you are saying but the book does say...

Additional protection shall be provided for all circuits of the location, by the use of one or more RCD's having the characteristics specified in Regulation 415.1.1 (thats a 30ma RCD)

No mention of any types of circuits....

:|

Just ALL circuits!

 

[Lurch]

No mention of any types of circuits.... :|

Just ALL circuits!

Yeah, that was what I thought you'd say.

Was just playing devils advocate for a change, wondering if one of the quotes the OP has received is interpreting the regs differently (as everyone does) and dropping the RCD if the lights and fan are SELV.

 

[ianmacd]

He does say Extra RCD which implys there may already be one.

 

[swisscheese]

thanks all for all your posts on this.

sorry for the confusion, I meant to say RCD in addition to the Isolator Switch.

lights and fans are all SELV.

Just so I know which is the correct situation.

In conclusion for the work to be done by the book and RCD needs to be fitted before the circuit hits the bathroom, then break in the isolator, then onto a junction box for the transformer onto the FAN, and Lights which I guess are OK to be daisy chained.

 

[Doc Hudson]

Hello Swisscheese welcome to the forum, I think some recommend it easier to RCD a circuit at the fuse box, there is often more room to connect up. Anyway some of our other members will probably be along later with their suggestions after work, so best to check back later. Meanwhile why not have a browse round the rest of the forum.

Doc H.

 

[ProDave]

I know what you are saying but the book does say...

Additional protection shall be provided for all circuits of the location, by the use of one or more RCD's having the characteristics specified in Regulation 415.1.1 (thats a 30ma RCD)

No mention of any types of circuits....

:|

Just ALL circuits!

Which is where certain aspects of the regs are an ass.

IF you touch either of the wires of an SELV circuit, it will NOT trip the RCD thus making it's inclusion rather pointless.

So the REGS say it must be RCD protected, but common sense (and the laws of physics) say RCD protection of the feed to an SELV transformer does nothing to protect the user (but by virtue of it being SELV it is a minimal hazard in the first place)

My guess is the difference in the quotes reflects one sparky doing it by the book and part P, the other just doing it so it works on the cheap.

That my friend is your choice.

 

[Lurch]

There's several ways of RCDing the wiring to the cloakroom.

• Run the feed to the new wiring through an RCD spur.
  
• Fit an RCD to the consumer unit to cover part of the installation, including the circuit for the WC (this depends on the CU and whether it's a feasible option).
  
• Fit an RCBO to the circuit feeding the WC (assuming it is a reasonably modern CU with DIN mounted MCB's).
  

Obviously the costs for the above can be quite different.

 

[septiclecky]

If the lights and fan are SELV and the 230V is all outside the bathroom does it need an RCD?

Assuming that it is not a electric shower but the person has not told us this, if it is an electric shower then it will need to be RCD'd

 

[Lurch]

Assuming that it is not a electric shower, if it is an electric shower then it will need to be RCD'd

Missed the shower in the OP, quite right. I was more referring to just the fan and lights, ignoring the shower. It would depend on the shower though, if it was also SELV then it's debatable, as above.

 

[septiclecky]

Missed the shower in the OP, quite right. I was more referring to just the fan and lights, ignoring the shower. It would depend on the shower though, if it was also SELV then it's debatable, as above.

Bloody hell I'd love to see the size of that transformer

 

[Lurch]

Bloody hell I'd love to see the size of that transformer

You've obviously never fitted a SELV shower then. The heater is located outside of the bathroom zones with a SELV control panel in the shower.

 

[swisscheese]

it's not an electric shower.

I'm guessing ProDave is right:

"My guess is the difference in the quotes reflects one sparky doing it by the book and part P, the other just doing it so it works on the cheap."

If I go for the cheaper options - no RCD - I'm guessing the Sparky will not be notifying the work...

 

[ProDave]

Another take on this.

IF the fan is not in the bathroom (perhaps an in line fan in the loft space) and ALL the new wiring is surface mounted or more than 50mm deep, no need for an RCD.

What about the lights? This discussion has centred on the fan, but if the lights are being altered, then they too might need RCD protection.

 

[swisscheese]

Don't think I can go inline on the extractor fan - joists in the way - so It will be wall mounted and because of space constraints - in Zone 1

 

[ianmacd]

You should check. At the end of the day, if you have no certificate from building control to cover the work, you will have issues selling your house. It has also been suggested that insurance companies may take issue too.

 

[Lurch]

If I go for the cheaper options - no RCD - I'm guessing the Sparky will not be notifying the work...

Possibly, but it might not be the case. It could just be 2 differing interpretations of the regulations. Worth checking, but then price ios just one part of the job, up to you as you're the customer. If you prefer one over the other, then pick whichever one you feel is best suited to doing the job to your satisfaction.