Clean/Dual Earth

[Dkeano76]

Hey all, just wondering if any can can give me some info regarding clean/dual earth. It's in a school computer room in dado trunking. Have an idea to what it is but not sure about terminating of it or what size 2nd earth (if that's the case) should be.
Cheers.

 

[Guest123]

http://www.electriciansforums.net/e...egulations/37201-high-integrity-earthing.html


Have a read.:wink5:

 

[Silly Sausage]

Look at page 129 in the old GN8.

 

[whaler]

read this hope it helps. if so click the thanks button

 

[Dkeano76]

Hey all, just wondering if any can can give me some info regarding clean/dual earth. It's in a school computer room in dado trunking. Have an idea to what it is but not sure about terminating of it or what size 2nd earth (if that's the case) should be.
Cheers.

 

[needasparks]

If the circuit is run as a ring then will be fine but twin earth terminal sockets have to be used with one leg in each, also each leg of cpc at the board must be terminated separately and not put together. the idea being that computer circuits dump current to earth so if an earth becomes detached it will still have a remaining earth parth, hence the separation of terminals.
the circuit can also be run as a radial but a second earth has to be run forming a ring on the cpc as it were. must admit IMO i prefere the ring method, as i'm not a lover of radials but if this is for a school its normally scheduled for you, have you checked ?

 

[GaryM]

Out of interest, how do you go on when you use two separate cpc terminals, one belonging to another circuit that requires that very same cpc terminal for it's own use?

 

[Guest111]

In my experience there are usually sufficient spare terminals on the earth bar for this not to happen.

 

[needasparks]

As Phil says, you should have spares.
Its also good practice to label the board with possible high earth currents blah, blah but importantly to label the cpc's of that circuit as the terminal numbers will not match for identification later by someone else.

 

[GaryM]

I've certainly used boards that don't have any spares.
Maybe the option would be to then install a second earth bar.

 

[Jimmy Boy]

I set one up last week in the regs mate

 

[jaresquire]

Just stagger the cpc's so it shares a terminal with another circuit, as long as there's two connections all's well.

 

[GaryM]

I'd prefer to install a second earthing terminal, marked up to show which circuits the cpc's belong to than to share another circuits terminal.
That way you can maintain circuit order and not have it listed as a defect when am EICR is carried out.

 

[jaresquire]

If the cpcs are labeled then no code applies, but each job is different and if there is space then fit (and label) another earth bar