RCD through RCD

[scottb]

I am installing underfloor heating in my bathroom and adding a spa bath. I wish to run the two items through their own RCD. Can I put the two RCD's on a ring circuit and just run the supply through one RCD and then the other and then allow the ring to contiue going on its path ?

I am just wondering if I trip the second in line RCD, that this would then trip the first.

I dont wish to sound thick but I just want peace of mind ...

Thanks

 

[Spark123]

Like this?
[code:1]
Ring---------RCD FSU-----RCD FSU--------Ring
| |
| |
Heating Bath
[/code:1]

 

[Steve]

depends on the rating of the bath and the UFH as to whether they can go on the ring.

 

[scottb]

Like this?
[code:1]
Ring---------RCD FSU-----RCD FSU--------Ring
| |
| |
Heating Bath
[/code:1]

Yes - I will be using the PowerBreak model (30ma). The location of the two RCD'S are within 1 meter of the consumer unit - any problems with that ?

 

[Spark123]

What are the current rating of the underfloor heating and bath? What else is the ring main used for?
Given the close proximity to the CU it may be better to a new another circuit.
Also, so you are aware of the rules (England+Wales), please see:
Ban-all-Sheds part p summary
Rules for electrical safety in the home
Statutory instrument (the Law)
Approved document P

 

[ban-all-sheds]

I am just wondering if I trip the second in line RCD, that this would then trip the first.

No it won't, but if the ring itself is RCD protected then there is no guarantee that an earth fault on the load side of one of the RCD FCUs will trip the local one instead of the main one, or that it won't trip both.

 

[megawatt]

My money's on both

 

[Cork]

Hi, There is an interesting document on RCDs at http://www.etci.ie/docs/ET214-2005.pdf The ETCI are the Irish equivelant of the IEE. Both UK and Irish standards for wiring regulations are very similar. The advice in this document should hold up.
http://www.etci.ie/faq/faq.html has some more general info.