bathroom fan RCD

[martysparky]

I was reading on another forum the other day and there was much confusion about if a SELV circuit fir a bathroom should be RCD protected.

Some said it should, some said it does not need it because its 12 volt.

I'm wondering if the difference is if the fan is located in the equipotential zone or not.

I would like to hear some views on this and how to connect the SELV / RCDFCU....

Just to be clear.

Thank you

 

[GT1]

It is indeed a minefield... and lots of grey areas to play with.
Which zone are you intending fitting the fan into..?

 

[cbw]

My thought is that regardless of zone you are extending a circuit, not all of which is selv so therefore the part you are working on needs to be up to current standard.


RCBO for whole circuit, pointless just rcd for the extended bit.

 

[Benn]

I do a lot of work in bathrooms with lv fans. I usually rcd, either by using an RCBO or moving the breaker on to the rcd side, the circuit thats feeding the fan.

 

[electric-ian]

Not sure that if its a Separated ELV supply a fault would cause an imbalance in phase and neutral supplying the transformer for the RCD to detect?

but unless you're using the old fan feed with existing isolator you probaby need one to cover your wiring anyway.

 

[cbw]

Yep your right, its not seperated, stupid boy!!!!!!

 

[martysparky]

Safety Extra Low Voltage....

Yep your right, its not seperated, stupid boy!!!!!!

Could you elaborate on that why not selv?? Cheers

 

[cbw]

SELV does stand for seperated extra low voltage and is what it says, basically the circuit is kept seperated from low voltage circuits(230) and is not connected to earth.

I have allways hated this subject and would appreciate someone giving a better deffinition!

I believe mains doorbells with transformer at the CU are selv circuits.

 

[Sintra]

FELV (functional extra low voltage) is an extra low voltage system (up to 50v ac, 120v dc) without all of the protective measures applied to PELV or SELV. p24. For more detailed information on FELV see 411.7, 612.4.4
PELV (protective extra low voltage) is an extra low voltage system (up to 50v ac, 120v dc) with a connection to earth. p27 For more detailed information on PELV see 414.1, 612.4.2
SELV (separated extra low voltage) is an extra low voltage system (up to 50v ac, 120v dc) with no connection to earth. p29. For more detailed information on SELV see 414.1, 612.4.1

 

[martysparky]

Cheers for all the replies I guess the general consensus is to RCD all in a bathroom even SELV but am still in doubt if the extra safety cost is really needed on a ELV as I understood it that ELV was the protective measure.

e.g. The lighting circit in the bathroom does not need RCD protection because USUALLY, and only when it is, the fitting is located outside the equipotential zone and is protected by the correct IP rating for Part P.

Any body agree?

 

[Guest123]

ALL circuits in a bathroom require 30mA RCD protection regardless of what type and where they are.

701.411.3.3.

 

[martysparky]

ALL circuits in a bathroom require 30mA RCD protection regardless of what type and where they are.

701.411.3.3.

Thats interesting because what I just quoted is what I was told by the instructor on my EAL and Part P course.

I am in agreement with the above as you have stated.

Does that mean the best way to wire the upstairs light circuit is to have the bathroom at the end and run the light from a RCD/FCU if upstairs ring is not RCD from CCU?

Cant seem to find any reg to RCD a light circuit but am confused about that as new build require switches to be mounted under 1200 mm. Low enough for a Disabled person to reach out of a chairr but also low enough for a child to switch with wet hands.

 

[Guest123]

Thats interesting because what I just quoted is what I was told by the instructor on my EAL and Part P course.

That worries me slightly.....


Cant seem to find any reg to RCD a light circuit

Well unless all the switch drops are buried more then 50mm deep in the wall or enclosed in earthed metallic conduit the cables will require RCD protection anyway. By and large all circuits require RCD protection nowadays for one reason or another, hence the introduction of the dual RCD CU.

 

[martysparky]

Well unless all the switch drops are buried more then 50mm deep in the wall or enclosed in earthed metallic conduit the cables will require RCD protection anyway. By and large all circuits require RCD protection nowadays for one reason or another, hence the introduction of the dual RCD CU.

Yes your right of course but I was assuming 50mm deep in regulated zones.

Point taken and thanks

Dual RCD wherever possible then?