No RCD on entire installation

[Taylortwocities]

Or an RCD socket

But that does not provide the required protection for the buried cabling.

 

[Pete999]

OK

 

[DPG]

If you fit a 30mA RCD up front of the dis board then you risk the whole lot tripping out on an earth fault. And if it's IT stuff in there then your total leakage current is going to be heading towards the trip current of the RCD anyway I would have though.

 

[Stspark]

I'd be looking to install rcbo's on the worked on circuits. Why do you say there is no room for this? Generally rcbo is only about 20mm longer than a mcb.
Other than that, instruct the client to provide a specific written risk assessment for the omission of rcd/rcbo on socket outlets circuits, which will need to be attached to the eic or mwc, good luck with that! Rcbo for me

 

[Taylortwocities]

Generally rcbo is only about 20mm longer than a mcb.

Many many legacy CUs just physically do not have a spare 20mm above the existing MCBs. Older ones often have solid neutral busbars and other obstructions that just make fitting an RCBO an impossibility.

 

[Stspark]

Many many legacy CUs just physically do not have a spare 20mm above the existing MCBs. Older ones often have solid neutral busbars and other obstructions that just make fitting an RCBO an impossibility.

Fair point. Thinking of options to keep cost at a minimum for client and maintain compliance. Utilise the other spare way in the cu, use 2 pole rcbo generally they're the same shape as an mcb? Bottom line is, an rcd is required unless a written risk assessment is provided.

 

[Deleted member 26818]

Fair point. Thinking of options to keep cost at a minimum for client and maintain compliance. Utilise the other spare way in the cu, use 2 pole rcbo generally they're the same shape as an mcb? Bottom line is, an rcd is required unless a written risk assessment is provided.

No documented Risk Assessment is required for sockets intended for specific items of equipment.

 

[Ian1981]

There's 2 options for omitting rcd protection.

(a) where, other than for an installation in a dwelling, a documented risk assessment determines that the RCD protection is not necessary, or

(b) for a specific labelled or otherwise suitably identified socket-outlet provided for connection of a particular item of equipment.

Obviously additional protection is still required for cables in walls etc etc

However these options look like they are being scrapped when the new 18th edition is in forced

 

[Taylortwocities]

As ian1981

I do not believe there is the option of a risk assessment for a domestic premises.

And I think that option b) will not be allowed when the 18th edition comes into force.

 

[Stspark]

When installing additional sockets to an existing non-rcd circuit with already a number of socket outlets with cables not mechanically protected buried in walls less than 50mm, in a commercial premises. For me 'Specifically labelling for a particular item of equipment' is not generally practical, as the socket outlets across the entire circuit worked on could be used for any number of purposes by employees or public. RCD or the risk assessment route clears up any confusion.