Office wiring...

[Boberto]

Been asked to add and move alot of sockets in an office as they expand the work force. I imagine theres work moving and adding extra lights etc also. 3-4 consumer units require upgrading. Earthing conductors need upgrading too.

My question is this. With regards the extra socket (25+). I had planned to wire these on 2 or 3 ring final circuits. The sockets are going to be used at desks supplying computers, printers, telephones, fax machines, scanners etc etc. All socket outlets are going to be wired in trunking. Not buried in the walls. I am aware the regs require RCD protection for socket outlets etc but have read that sockets marked "computer only" dont if they are meant to supply a single appliance etc. In this office's case there is other equipment going to be plugged in like the phone, scanner, fax machine, desk lamp?, printer etc so whats the score? From others experience do you RCD all socket outlets or not?

Also the upgrading work with the DBs. Currently no circuits are RCD protected. Should the ring finals on these boards supplying existing sockets now require RCD protection? No wiring n the building is sunk in walls, all trunking and above suspended ceilings.

Would appreciate some advice. I know its always best to follow the side of safety but I would hate to install the work to find the PCs and other equipment are causing nuisance tripping as ive heard IT equipment can do this. All help appreciated

 

[Sparky Ninja]

First you need to make an assessment of the users of the installation and identify if there are any competent/skilled persons in control of the installation.

 

[Boberto]

Just office staff mate. Women in suits etc.

 

[Sparky Ninja]

Who is the supervisor/employer?
Who responsible for conformity to the EAWR?

If you cannot identify a competent/skilled individual then you'll be throwing RCD's everywhere.

Buy the boss a picture, and observe who they choose to put it up. There is your individual.

 

[Simlec]

For me,
your sockets feeding computers should be pages 67 & 68 osg
also the socket outlets feeding there computer server (if they have one) should not have RCD protection.

 

[nickblake]

get the old dado trunking out great for this type of work easy to change about and add extra ,also look at bench trunking but like has been said check whats being installed and loadings etc

 

[Boberto]

Ive got the trunking/installation side of things sorted ta mate. Just need to know if RCD is a must in office environment to protect sockets for pc's etc???

 

[Dunc]

If you can avoid burying any of the cabling in walls or partitions then you could fit RCD sockets everywhere. Not pretty or cheap but a single fault will only cause the faulty PC to stop working.

 

[Sparky Ninja]

Make sure you consider protective conductor currents too.

 

[Simlec]

As said before it depends on your/there risk assessment.
If computers are to be RCD protected then i always work on 5mA per desk (desk = 1pc, 1monitor, phone ect) yes some will say 5mA is high but i very rarely get problems/call backs adopting 5mA.
So with a 30mA RCBO i go up to 20/25mA or 4-5 desks per RCBO, there could be 2,3 or 4 double socket outlets per desk.

 

[Short Circuit]

Had a similar job recently, as already stated, if the sockets are for use of computers only, and marked as such, then no, you dont need the RCD protection but there must be a general use socket in that room and if that isnt already in there, it will need RCD protection - so if only one of your new sockets is for 'general use', then you need an RCBO - but you need to keep a close eye on how many computers will be on it for the earth leakage and tripping!

 

[Boberto]

No the sockets will supply a mixture of office desk type equipment not just a PC. Think I might wire small circuits. 4 or 5 sockets per RCBO, as said previously, that way if a fault occurs it doesnt trip out the whole office. What about the existing sockets? By upgrading the DBs of existing circuits it would mean incorporating RCDs at the premises for the first time. Got a feeling I might be opening a can of worms but hey ho its work and its got to be done...

 

[Boberto]

Just one other quick question. Its with regards some equipment and RCDs. I remember around 2008 with the new regs we were now told ALL circuits required RCD protection if the circuit cables were containined in a wall at a depth of less than 50mm etc etc. There was much debate about the effectiveness of RCDs. Some points were raised about some appliances/equipment having a "natural earth leakage". Wasnt sure what this meaned and still dont. I remember fluorescent luminaires were one of the items mentioned. I was wondering if theres any truth in this and is IT equipment in its many forms a contender for this? If such equipment exists.

I guess this theory id read about back then prompted me to start this thread as I was unsure whether computers etc were chief culprits for nuisance tripping for no explainable reason...?

Might just be talking b0ll0cks here but just throwing stuff I read back then on similar message boards into the mix