17th

Help Support Talk Electrician Forum:

benji

Senior Member
Joined
Jul 11, 2008
Messages
131
Reaction score
0
just been told that installing a ringmain to the 17th that at the db/cu the cpc's have to go in seperate terminals on the earth bar?also if you ran two radials along two walls it would be good practice to link the last two outlets with a conduit containing a earth wire connecting to the earth on each radial.

the first item i've done before on rings for IT rooms but the second ???

yours benji

 

DonkeyDong

TEF Newbie
Joined
Mar 14, 2008
Messages
218
Reaction score
0
Hi,

High integrity earthing is for IT equipment (or equipment that has a high earth leakage):

As for putting the earths into two earth terminals - I've always used two, with the cables clearly labelled.

I've never linked the earths/conduit on radials.

D.

 

seajayess

Senior Member
Joined
May 28, 2008
Messages
272
Reaction score
0
Do you mean you use 2 separate connections for the CPC at the CU or at socket connections. If using 2 separate connections at CU they will not be in the correct order for the Neutrals and the MCB CJS

 
Joined
Feb 14, 2008
Messages
7,480
Reaction score
21
Location
Cloud Cuckoo Land
Benji, you need to read reg 543.7 Its titled 'Earthing requirements for the installation of equipment having high protective conductor currents'

Most domestic wiring does not have this so there is no need for your suggestions. Who ever told you this has just learnt about 543.7 and is confused with everyday normalities.

 

benji

Senior Member
Joined
Jul 11, 2008
Messages
131
Reaction score
0
whats been said is that every earth on ringmains at the cu/db have to be in individual terminals on the earth bar not terminated together in one terminal as you would for the neutrals

yours benji

 

benji

Senior Member
Joined
Jul 11, 2008
Messages
131
Reaction score
0
this came from somebody tutoring an in-house 17th course+exam

yours benji

 

steptoe

of course Im wrong, ask my wife™
Joined
Feb 13, 2008
Messages
24,337
Reaction score
117
Location
Gtr Manchester
I think that is total male cow droppings!!!!

never ever have I put two cables belonging to the one circuit in different terminals, that is just total tat. I think this guy has got mixed up with sleeving them seperately,(which has always been the proper way anyway), and not two cpcs in one piece of sleeving, which I see all too often on jobs done by monkeys and prats that think they know better!!!

 
Joined
Feb 14, 2008
Messages
7,480
Reaction score
21
Location
Cloud Cuckoo Land
this came from somebody tutoring an in-house 17th course+exam yours benji
I was correct then in my earlier post. Separate terminations are only necessary for circuits with a high Protective conductor current, of course there would be nothing wrong in doing this all the time, just unnecessary. Your tutor may be thinking ahead when all equipment may need this. Have you read reg 543.7 ?

 

NWDS

Senior Member
Joined
Jun 18, 2008
Messages
167
Reaction score
0
when I did the 17th it was mentioned that we may have to number neutrals/cpcs, this is mainly for when you are testing circuits .

regards IainGuiness Drink

 

Admin1

Forum Founder
Joined
Feb 6, 2008
Messages
10,278
Reaction score
-1
I said the same as DD when I did mine, but the lecturer said (seen it in the regs somewhere too) that they have to be terminated in the CU MET at different terminals. (Just like that of a ring supplying IT equpment).

 
Joined
Mar 28, 2008
Messages
13,618
Reaction score
296
Well standard practice has always been to ensure identification of circuits by numbering of terminations along bus-bars to compliment the relative MCB position.

The NICEIC inspection & Test book (haven't seen latest if updated for 17th)

states

wiring in equipment should be identified by arrangement. This usually means connection of the neutral and cpc of each circuit to the terminals which relate specifically to the associated outgoing fuse or circuit breaker, by sequence or terminal marking
On Site Guide Pg 67 gives a picture of ring, specifically relating to High protective current (exceed 10ma).

I would be VERY interested to see a regulation that says EVERY ring circuit must be wired this way????

cuz I don't remember any mention of it on my 17th ed. 2382...

but it was back in April when I passed it (100%) !! :| ?:| ? :| ?:|

 

DonkeyDong

TEF Newbie
Joined
Mar 14, 2008
Messages
218
Reaction score
0
As has been stated, 99% of the time for the circuits you come across, you use the same terminal for the cpc in the cu/db - sleeved separately too :)

Its under certain circumstances or specific design (that some/most of you won't come across) do you use separate terminals for the cpc.

D.

 

Admin1

Forum Founder
Joined
Feb 6, 2008
Messages
10,278
Reaction score
-1
I haven't got my regs book no more. :(

I am going to become a Plumber and start a plumbing forum. :_|

 

Admin1

Forum Founder
Joined
Feb 6, 2008
Messages
10,278
Reaction score
-1
On a S/O on a ring where you have two seperate Earth terminals, do you guys place one cpc at each termination or place them into one terminal?

 

DonkeyDong

TEF Newbie
Joined
Mar 14, 2008
Messages
218
Reaction score
0
on a hi ring you are meant to use the separate earth terminals on the s/o, but be careful as not all s/o's have two terminals. I always stick to crabtree in commercial jobs.

D.

 
Joined
Mar 28, 2008
Messages
13,618
Reaction score
296
On a S/O on a ring where you have two seperate Earth terminals, do you guys place one cpc at each termination or place them into one terminal?
The two earth terminal socket outlets have been made to specifically meet the requirements of 543.7.1.4, High protective earth currents.. cpc's must be termination independently of each other.. in j/box/ socket/ CU.. so accessories must have two earth terminals.

If the circuit is NON-IT.. 'low cpc' current can terminate how you like....

When installing new sockets with two terminals I use them, whether needed or not! ;)

 
Top