rcd protection

[sijaysee]

does this sound right?
one way to deal with 17th regarding rcd protection if no
rcbo's will work would be to take for instance the ring main
out of the mcb and take it through a stand alone rcd unit
and back into the mcb

 

[securespark]

Don't think so!

You can use stand alone RCD's to give protection to individual circuits, however not in that fashion.

Further, I'm not sure if it's good practice to use a 6mm² cable to feed the incomer of an RCD, then run the ring from the outgoing terminals...

 

[sijaysee]

umm just was wondering because its one of the ways that my
h&s have said that is an acceptable way of dealing with
the new regs

 

[securespark]

Your who?

 

[GaryMo]

Secure, why not?
Nothing at all wrong with inline 30mA RCD protection as long as the feeding cable doesn't require RCD protection, nor 6mm conductors supplying the feed terminals of the RCD (did he mention 6mm conductors though?).
6mm conductors will happily supply 32A though the size of the 2.5mm cpc (if using t&e) would require calculating to see if it meets requirements (probably will though). If you don't want that hassle then just run a separate 4mm cpc.
It may not be conventional though that doesn't mean it's wrong.

 

[sijaysee]

secure h&s = health and safety

 

[securespark]

Not happy with a RF that begins life as a radial.

Yet another reason I'm going off RF's.

 

[GaryMo]

Not happy with a RF that begins life as a radial.

As I said, not conventional though that doesn't mean it's wrong.
The radial would be around 300mm long so hardly the end of the world. Also consider this option may fall into somebodies budget whereas a consumer unit change may not.

So, fully compliant or do you think it contravenes BS7671:2008 in any way?
I assume by saying an inline RCD can't be used in that fashion you may be thinking it's non-compliant in some way?

 

[ColJack]

Not happy with a RF that begins life as a radial.

Yet another reason I'm going off RF's.

technically, all RF's start as a radial..

the busbar from the main switch is a radial, the tails from the meter to the CU isolator is a radial..