How to wire cpc in class rooms

[bs7671]

Hi there my question is if you were installing a final circuit in a computer room for IT purposes,how would you wire the c.p.c.I think maybe it is something to do with a switchmode something or two earths???I have looked but cannot find anything specific to answer this.Help appreiciated thanks guys n gals

 

[telectrix]

unless it is specifically stated that earth free sockets are required, I would wire them normally. What do others think

 

[djb_1983]

The NIC told us that for IT equipment and areas using computers you need to use sockets with two earth terminals and connect each cpc seperately. Also at the distribution board the two cpc's from your ring need to be terminated in seperate terminals on earth bar. Not sure what reg number was tho.

 

[bs7671]

djb_1983 good answer but where else could I find out the infomation from a formal source

 

[djb_1983]

There are diagrams in on site guide with relation to this , from memory im not too sure what page its on. Hope that is of help to you.

 

[Spudnik]

543.7.2.1

which relates back to 543.7.1

 

[Deleted member 9648]

It is because of the potential for high earth leakage on IT equipment....the regs are to ensure that each outlet will maintain a cpc connection even if one cpc becomes disconnected. The cpc's must be run as a ring whether the circuit is a ring or radial and each cpc must be connected to a separate terminal at each socket and at the DB.

 

[jeremy]

Just throwing one in here but if the earth positions are already marked by manufacturer, and the rest are full how do you do seperate earths in CU. Crimping makes the 2 ends " one conductor" ( I think). Could they then go into the same point on the earth bar?

 

[telectrix]

excellent answer, wirepuller. clarified the post exactly. as to jeremy's post, wouldn't it be a good idea for CU manufacturers to add a couple of extra holes in the earth bar, for this very purpose?

 

[Sintra]

What you are permitted to do is this.

CPC 1 from circuit 1 in terminal 1 along with CPC 1 from circuit 2
CPC 2 from circuit 1 in terminal 2 along with CPC 2 from circuit 2 etc etc.
Using this method takes up no extra ways on terminal block. This is only acceptable if the CPC's are all marked with their correct circuit number and the cu is labeled accordingly.

 

[jeremy]

excellent answer, wirepuller. clarified the post exactly. as to jeremy's post, wouldn't it be a good idea for CU manufacturers to add a couple of extra holes in the earth bar, for this very purpose?

You're right, it would!! but what are the chances?

 

[telectrix]

and, whatever happened to the removable earth link so one could split the main earth to get Ze. only reason i can think of is if some careless sod left it off, but same careless sod could leave the earth cable out. either way would show up when Zs readings were taken

 

[jeremy]

What you are permitted to do is this.

CPC 1 from circuit 1 in terminal 1 along with CPC 1 from circuit 2
CPC 2 from circuit 1 in terminal 2 along with CPC 2 from circuit 2 etc etc.
Using this method takes up no extra ways on terminal block. This is only acceptable if the CPC's are all marked with their correct circuit number and the cu is labeled accordingly.

i can see the reasoning behind it but it seems a bit trusting of those following?

 

[Sintra]

As long as the guy following is competent enough to know about high integrity earthing then there shouldn't be a problem. If he isn't competent he shouldn't be near it.

 

[Deleted member 9648]

I can see this becoming a general requirement in the forseeable.....the justification being the ever increasing use of IT equipment in the home......probably worded 'any circuit supplying socket outlets which may reasonably be expected to supply an item of IT equipment'....which of course would mean an amendment...all buy another regs book,guidance notes,courses......DOH!