Hw many computers for no RCD

[Fazz711]

We have to put two new tower sockets in to a office at work.
At the moment we have two towers but four sets of four desks.
The two sets of four without towers are fed via extension leads hence the need for two new towers.

I have been told by our tech guy we aren't fitting RCBO on the two new circuits.
There will likely be 16 off sockets on each tower but only four will be used for laptop stations.

The other sockets will be monitor phone and a spare for each desk.

I still think like all the other offices with computers they still need protection.

We have two floors of large open plane offices and several sub offices and they are all covered by RCD including the other towers I think.

So what do the real experts think RCBO or not.?

 

[MJPD29]

Socket outlet in an office, Cabling may require rcd protection and always the possibility of a hoover or something being plugged in. Definetly a yes for me

 

[mainline]

We have to put two new tower sockets in to a office at work.
At the moment we have two towers but four sets of four desks.
The two sets of four without towers are fed via extension leads hence the need for two new towers.

I have been told by our tech guy we aren't fitting RCBO on the two new circuits.
There will likely be 16 off sockets on each tower but only four will be used for laptop stations.

The other sockets will be monitor phone and a spare for each desk.

I still think like all the other offices with computers they still need protection.

We have two floors of large open plane offices and several sub offices and they are all covered by RCD including the other towers I think.

So what do the real experts think RCBO or not.?

It's down to the installer and his documented risk assessment.

 

[Fazz711]

It's down to the installer and his documented risk assessment.

The designer isn't doing the installation.
If there is a risk assessment I won't get to see it unless I demand it.

I will most likely be the installer as I work permanent nights so can be done when no one in the office.

I want RCBO as at the moment there are other things like Xmas trees plugged in.

Unlikely cleaners will use as it won't be easy to get at in the centre of a block of four desks and other sockets easily got to for vacs.

This may have to be one we butt heads on with me refusing to have anything to do with the job then facing a disciplinary.
Which I will do.

 

[MJPD29]

Are you an electrician? Almost certainly it will require rcd protection. It would be interesting to see the risk assessment that states otherwise.

 

[Fazz711]

Are you an electrician? Almost certainly it will require rcd protection. It would be interesting to see the risk assessment thay states otherwise.

Multi skilled maintenance engineer.
Started as mechanical engineer but mainly repairing electric motors for D&M.
Added electrical work later.
Where I am now I mainly do electrical work.

My thoughts exactly on the risk assessment which is why I don't think I will see one.

 

[James]

Sockets require an rcd.
simple, if you need more sockets and you expect leakage to be to high then add another circuit to split the leakage.
obviousley the circuits can’t be fed from the same rcd, so as a rule of thumb, expect 3mA leakage from each pc (including monitor etc.)
so 10 desks from each rcbo will normally work out ok.

 

[Fazz711]

Sockets require an rcd.
simple, if you need more sockets and you expect leakage to be to high then add another circuit to split the leakage.
obviousley the circuits can’t be fed from the same rcd, so as a rule of thumb, expect 3mA leakage from each pc (including monitor etc.)
so 10 desks from each rcbo will normally work out ok.

There will only be four laptop work stations per tower and each will have its own feed.
I would prefer to do 2 off rings but he wants radials

 

[westward10]

It's down to the installer and his documented risk assessment.

It is not for the installer alone to perform a risk assessment although being competent person (electrically) they can be involved. The risk assessment should be undertaken by the client/responsible person who understand the nature of the site along with the involvement of the electrician.

 

[mainline]

Sockets require an rcd.
simple.

It's not domestic.

 

[mainline]

It is not for the installer alone to perform a risk assessment although being competent person (electrically) they can be involved. The risk assessment should be undertaken by the client/responsible person who understand the nature of the site along with the involvement of the electrician.

I should have said:
The designer of a new electrical installation is required to obtain from the client a formal written risk assessment if RCD protection is to be omitted

 

[Fazz711]

I should have said:
The designer of a new electrical installation is required to obtain from the client a formal written risk assessment if RCD protection is to be omitted

With it being factory offices there is no cliant really.
The guy who has supposedly speced the job is our tech guy who normally deals with the PLCs and motor drives.
He also designs the new dual safety circuits.
He seems to be good at what he knows best but don't think he has done much insulation work.
I normally have to run all his cable jobs and coms cable runs.
He mostly connects the coms I do the power stuff.


Thanks for all the replies.
I have just been into the office to check the existing tower feeds and both are RCBO.
I thought they were at least RCD but they are much newer than most of the other circuits in that part of the office.
It must have been reconfigured more recently than I expected.

 

[littlespark]

Has any of you got a bs7671 qualification between you?


Would my esteemed colleagues agree that RCD sockets could be used here?
I seem to recall they were omitted from some list of suitable RCD devices, but are they back now?

 

[newfutile]

If the cabling does not require rcd then as littlespark says rcd sockets are the way to go, socket circuits with no rcd are prohibited except in specially cases with a documented risk assessment.
where BA 1 ,2 or 3 (ordinary people, children or disabled people) may use them they have to have rcd .
reg 411.3.3 explains more.

 

[littlespark]

All very well an RA by the designer, and the installer if you get it, but the users should be privy to it too.

In the days where office staff need training for opening a window… (no joke!) they would need to be informed if there was a deviation from the standards.

 

[Fazz711]

Well after being assigned the job again after new bits arrived it now seems tech guy agrees with me and he has a RCBO.
Also found he has everything for a ring not a radial.
After questioning him as to which he wanted radial or ring as I was originally told radials he now wants ring.
After another quick question he has spat his dummy and said to leave the job and he is getting one of the other engineers to do it.

So thanks for the advice to everyone who replied

 

[littlespark]

This is why it would have been easier to get a spark in at the beginning. The job would have been done by now.

 

[Fazz711]

This is why it would have been easier to get a spark in at the beginning. The job would have been done by now.

Parts only arrived yesterday so could have only been started last night.

 

[mainline]

Well after being assigned the job again after new bits arrived it now seems tech guy agrees with me and he has a RCBO.
Also found he has everything for a ring not a radial.
After questioning him as to which he wanted radial or ring as I was originally told radials he now wants ring.
After another quick question he has spat his dummy and said to leave the job and he is getting one of the other engineers to do it.

So thanks for the advice to everyone who replied

He should use a DB and D/P Rcbos feeding radials, a single rcbo feeding all those SMPS is bound to have lots of earth leakage.

 

[Fazz711]

He should use a DB and D/P Rcbos feeding radials, a single rcbo feeding all those SMPS is bound to have lots of earth leakage.

At the moment the desks are fed from two existing towers with an RCD each in the DB.
8 times the amount of computers than will be on the two new towers.
Never been a problem.
The new towers are being fitted to do away with extention leads feeding the desks furthest from the towers.