60 outlets in one class.

[M107]

Small rush job had to be done in one day as chippy was due in next day.

30 pc's going in to boxing along with sockets, so the kids cant nick any of the hardware. All they have on the worktop is a screen a mouse & keyboard + an sd card slot on boxing.

http://i83.photobucket.com/albums/j293/gazjothomas/DSC00458.jpg

http://i83.photobucket.com/albums/j293/gazjothomas/DSC00457.jpg

http://i83.photobucket.com/albums/j293/gazjothomas/DSC00456.jpg

http://i83.photobucket.com/albums/j293/gazjothomas/DSC00455.jpg

http://i83.photobucket.com/albums/j293/gazjothomas/DSC00454.jpg

http://i83.photobucket.com/albums/j293/gazjothomas/DSC00453.jpg

Yes for expediency I used flex conduit in some bends.

 

[Apache]

Looks good

May I ask if it's through an RCD with all those computers?

 

[M107]

Through a 32amp 30mA memsheild2 type C rcbo patch, as per the schools request.

I did point out the potential problem, but they said they have another class wired the same & have had no problems to date, but they do have to fire the pc's up in groups with 2 min intervals...all done remotely from the IT office.

 

[Sidewinder]

I guess the school personnel will be signing the design section of the cert then...

:^O :^O:^O

:coat

 

[Apache]

Through a 32amp 30mA memsheild2 type C rcbo patch, as per the schools request.I did point out the potential problem, but they said they have another class wired the same & have had no problems to date, but they do have to fire the pc's up in groups with 2 min intervals...all done remotely from the IT office.

Isn't technology wonderful

 

[green-hornet]

I did a similar job but it was run under worktop in dado with data cables.

Same as you I was given a day to fix before the joiners came in to complain about any cuts to get around the trunking

 

[bengie]

i wish them luck with RCD's, my brother used to work for a college and they had to split each calss room from 1 to either 2 or 3 circuits to stop them tripping the RCD. sounds like a better plan than staged start ups.

 

[a1]

I see that "Henry" was turning a blind eye. (Or watching you and wanted to be in on the photo).

 

[M107]

I see that "Henry" was turning a blind eye. (Or watching you and wanted to be in on the photo).

My work mate (in the pictures) forgot to pick up Dave (the blue version) so we raided the cleaners cupboard & found Henry the photogenic sucker.

 

[VoltzElectrical]

i was under the impression that computers leaked up to 3 mA each so it is pertinent to put no more than 10 on any rcd protected circuit so to avoid nuisance tripping problems. hope to be corrected on this, as always willing to listen and learn from the amazing contributors to this site. respect to all.

 

[ianmacd]

i was under the impression that computers leaked up to 3 mA each so it is pertinent to put no more than 10 on any rcd protected circuit so to avoid nuisance tripping problems. hope to be corrected on this, as always willing to listen and learn from the amazing contributors to this site. respect to all.

I would say thats about right.

 

[Lee321]

could have negated the need for rcd quite easily imo

 

[sparkytim]

Schools pretty keen on RCD protection

 

[Sidewinder]

Schools pretty keen on RCD protection

BS4163:2007 has quite a lot to say on the matter!

 

[SLIPSHOD & SLAPDASH]

Should you not have an additional CPC ?

 

[M107]

Should you not have an additional CPC ?

Wired as a ring with seperate earth terminals at accessories & seperate cpc terminations at DB.

 

[Lee321]

BS4163:2007 has quite a lot to say on the matter!

specifically paul?

 

[bengie]

i never really saw the point in using seperate earth connections at sockets/fuseboard but have been made to do it due to spec.

 

[ianmacd]

i never really saw the point in using seperate earth connections at sockets/fuseboard but have been made to do it due to spec.

So if one becomes loose and falls out you maintain your earth (although you would likely never know anyway).

 

[ian932]

i never really saw the point in using seperate earth connections at sockets/fuseboard but have been made to do it due to spec.

Its due to the IT kit leaking around 3mA per unit through the switch mode psu. this number of pc's could cause a lethal shock if a single earth were lost so the BS calls for it as a forum of redundancy in these applications.

Through a 32amp 30mA memsheild2 type C rcbo patch, as per the schools request.I did point out the potential problem, but they said they have another class wired the same & have had no problems to date, but they do have to fire the pc's up in groups with 2 min intervals...all done remotely from the IT office.

I'd be surprised if the start up sequence stops the unwanted tripping. I tested a job a few months ago using an old multimeter set to 200mA range and got a continuous 12mA from 10 desktops once they had booted and stabilised, so taking into account that most RCD's I test trip from 20-27mA I'd say 30 has got to trip the RCBO unless they have very clean psu's.

The phased boot is likely to only stop it tripping on overload than leakage