RCD protection on Office socket - Three phase board.

[spark 68]

HI Earthing cont.

I need an earth going back to the board??

Here is an extract from GN8, for the final socket outlets, to be used in conjunction with the wiring matters article earlier.

This shows a bit clearer the connections required.

 

[Dunc]

RCD socket outlets is the way forward in my opinion. Not a cheap method but a single fault will cause only one socket to stop working and you're completely covered on the grey area of 'supervision by skilled persons'.

 

[cprfenom]

for the IT sockets, a radial is fine, but you need to install hi integrity earthing.

I know this is an old thread, but do you always install a high integrity earth to circuits supplying computers or do you check to see if there is 10mA to the cpc on that circuit first?

Also sockets on the same pillar that don't have PC's plug in would you consider RCD sockets?

I only ask because being a newer to the party than some here, I wouldnt trust employees to be considered instructed under the EAWR regs

 

[DPG]

Don't the latest regs say that, for commercial stuff, if an RCD is deemed not necessary then a written risk assessment needs attaching to the installation cert? Daz

 

[telectrix]

I know this is an old thread, but do you always install a high integrity earth to circuits supplying computers or do you check to see if there is 10mA to the cpc on that circuit first?

Also sockets on the same pillar that don't have PC's plug in would you consider RCD sockets?

I only ask because being a newer to the party than some here, I wouldnt trust employees to be considered instructed under the EAWR regs

regs. have changed. the skilled instructed personnel are history. to omit RCD ptotection now requires a written RA. most of us would now insist on RCD protection for all sockets <32A, and for cables in walls <50mm, for use in office/factory environments. consideration would need to be given to IT equipment , usually by ensuring < 10 items per circuit.

 

[Deleted member 26818]

Is it Easter?

 

[telectrix]

^^^^ ????

 

[K Macnamara]

What is worth taking into account is that PC's use the earth (cpc) of a circuit to "dump" the kinetic power they accumulate. I could probably find out the finer details of why but for now just take it as a given that they do. If you assume that one PC will discharge between 0.85 to 1mA a circuit with approx 30 PC's is going to trigger the RCBO. I found that out by insisting all sockets should be RCD protected and had to deal with this issue. So if you are also satisfied that the floor boxes are to be used solely for the purpose of powering PC's that should be floor boxes covered.

Usually in an office the other items of equipment that office staff plug in are mobile phone chargers, fans in the summer and heaters in the winter. The regs state that a suitable risk assessment and method statement should be in place where sockets with no RCD protection can be used by those not instructed to
.
One thing that is very important to remember though is to see if all the socket outlets on the Distribution Board you are working on are on the same phase. Who knows when an extension lead may find itself close to another outlet that's on a different phase giving you a potential 415 volt accident.
Cleaners sockets, Kitchenette areas and others for example dado trunking I would protect as you could assume these are to be considered for general use.

For essential supplies such as servers, you can cover yourself in a number of ways where RCD protection may give you nuisance tripping. These being Labeled "Server Equipment Only NO RCD PROTECTION", change the outlet to a commando socket or as the regs state permanently connected items should be supplied from a fused connection unit and not exceed 20A.

Whats stopping you from installing a new circuit? If its not practical to protect the whole circuit with an RCBO you could protect those that you deem to pose a risk with an outlet with RCD protection included.

I always look at any scenario with the view of If I'm unhappy with it and its dangerous, make it safe by isolating the supply. Highlight the issue to the owner of the installation and document the fact, Then its up to them.

 

[cprfenom]

Thank you for the informative replies.

The reg change seems to be a hard pill for employers to swallow.

The problem I am having is that I feel the risk assessment is too generic. I have gotten them to produce a risk assessment for the staff and I will replace the other sockets that the public can access with RCD outlets. The wiring was completed in 95, so strictly only sockets that can be used outside should be RCD protected.

Funny thing is that I replaced a damaged wooden backed 3036 Wylex board in the same building and put all circuits on RCBO's without any protest.

Its a cost thing as they have 10 circuits in a 48 Way board that could benefit from RCD protection.