RCD for Bathroom Lighting

stevesar · Posted: Wed Feb 22, 2006 11:24 am Post Subject: RCD for Bathroom Lighting

Dear DIYnot, I wish to install Zone 1 designed downlighters over bath and understand I need a 30ma RCD in the lighting circuit for proper protection.
The relevant lighting circuit goes back to 5amp MCB in a Wylex 804 Consumer Unit (BS5486 Pt13) about 20 years old.
Is it possible to replace the MCB with a dual function MCB/RCD that will just plug in or am I into more complicated territory? There is no general RCD on the CU. Many thanks

Pens · Posted: Wed Feb 22, 2006 12:15 pm Post Subject: Re: RCD for Bathroom Lighting

stevesar wrote:

Dear DIYnot, I wish to install Zone 1 designed downlighters over bath and understand I need a 30ma RCD in the lighting circuit for proper protection.
The relevant lighting circuit goes back to 5amp MCB in a Wylex 804 Consumer Unit (BS5486 Pt13) about 20 years old.
Is it possible to replace the MCB with a dual function MCB/RCD that will just plug in or am I into more complicated territory? There is no general RCD on the CU. Many thanks

The information you have been given is incorrect. The light fitting, if metal, needs to be bonded to other metallic objects within your bathroom but it does not need to be feed via an RCD

Adam_151 · Posted: Wed Feb 22, 2006 1:58 pm Post Subject:

The way I understand it, a light fitting in zone one has to be IPx4 rated, and if mains has to be protected by 30ma rcd obviously you don't need an RCD if its selv, when you think about it, its very strange that you don't need an rcd for an electric shower

The following quote lists what you can install in zone 1

NICEIC article on zones and bonding wrote:

The following fixed current-using equipment
provided it is suitable for the conditions of the zone:
• a water heater
• a shower pump
• other fixed current-using equipment which can
reasonably be located only in zone 1, providing
the supply circuit is protected by a residual
current device having a rated residual operating
current, IΔn, not exceeding 30 mA in accordance
with Regulation or Regulation Group 412-06.
• SELV current-using equipment.

JohnD · Posted: Wed Feb 22, 2006 3:23 pm Post Subject:

Have you not got the message that putting 230v lights in zone 1 is such a bad idea that it would be less trouble not to?

Pens · Posted: Wed Feb 22, 2006 3:35 pm Post Subject:

<wrongly assumed downlighter was SELV

stevesar · Posted: Fri Mar 10, 2006 10:22 am Post Subject: Zone 1 Lighting

Thanks to everyone for their advice. Sorry to take a while to reply but have heeded advice, and Zone 1 now has a very nice 12V light with transformer, everything else safely away in Zone 3, regards stevesar