MICC cables sunk in a wall

[conyers292]

Whilst doing periodic inspection and testing at my local town hall I noticed alot of MICC cables sunk in walls for lighting circuits i looked in my onsite guide to see if these needed RCD protection but after reading what it said i was none the wiser due to the on site guide being very misleading to cover itself.......

The pyro`s having earthed sheath but wer sunk in at a depth of less than 50mm can a cable with an earthed sheath such as a pyro get around being protected by an rcd at whatever depth it is sunk in the wall at?

Can someone please straighten this out for me?

Thanks in advance!

 

[pennywise]

I would say it doesn't need RCD protection as MICC gives mechanical protection that would obmit the use of RCDs. However you may need RCD protection for circuits feeding things in special locations or power circuits with the potential for portable appliance to be taken outside of the hall.

 

[gaffer]

Never thought of it that way.Dont the regs say"earthed metallic sheath"sort of answers your question.

 

[Darkwood]

No need for rcd protection as its surrounded by a earth just like a swa that can withstand a short circuit, if you pierce it with a nail, drill etc then the nail or drill will always have earth contact before touching live thus a fault potential going through joe bloggs is unlikely as it will always go down the sheath, providing it tests out ok for earthing.

 

[Davey101]

Quick answer- no they do not require RCD protection.

Edit- already answered by others

 

[mechelec]

If you consider fitting an RCD to feed an MICC cable check the insulation resistance first as they are prone to absorbing moisture (hygroscopic), giving low readings and tripping RCD's

 

[conyers292]

cheers guys me and a co worker were having a discussion about it i didnt think it needed it....he thought it did