High integrity earthing

[ban-all-sheds]

A protective conductor can link an exposed conductive part to the MET, theres two independant links from each point to the MET.
Is it fair to say there are two independant protective conductors from each point to the MET?

Only if you believe that you could completely remove all of independent protective conductor #1 and be left with a normally compliant independent protective conductor #2.

If you can't remove one to leave one then you didn't have two in the first place...

 

[ban-all-sheds]

Although as softus points out 607-03-01 contradicts 607-02-04.

No it doesn't.

607-03-01 says that a ring protective conductor is acceptable.

607-02-04 says that a single protective conductor is acceptable - it just can't be 1.5mm².

 

[ban-all-sheds]

It looks like BAS has given up now

Just out for the day....

 

[Softus]

Although as softus points out 607-03-01 contradicts 607-02-04.

No it doesn't.

As persuasive as that argument might be, I'm gonna go ahead and continue to think that there is still a contradiction.

607-03-01 says that a ring protective conductor is acceptable.

The 16th Edition doesn't say that - those are your own words, and they have a different meaning.

607-02-04 says that a single protective conductor is acceptable - it just can't be 1.5mm².

The 16th Edition doesn't say any such thing.

 

[THRIPSTER]

Softus wrote:-

'But the 16th Edition also says this:

607-03-01

...the circuit shall be provided with a high integrity protective conductor connection complying with the requirements of Regulations 607-02 and 607-04. The following arrangements of the final circuit are acceptable:

(i) a ring final circuit with a ring protective conductor.
.
.
.

So which section is correct?'


You are partially correct but the pre-amble to 607-03-01 (which you have omitted) also states: -

For a final circuit with a number of socket outlets..............the circuit shall be provided with a high integrity protective conductor complying with the requirements of 607-02 and 607-04.


607-02-04 states:-

The wiring of every final circuit and distribution circuit intended to supply one or more items of equipment , such that the total CPC current is likely to exceeed 10mA, shall have a high integrity protective connection complying with one or more of the following:-

(i) A single protective conductor having a cross-sectional area of not less than 10mm squared complying with the requirements of regulations 543.2 and 543.3

(ii) A single CPC of not less than 4mm squared complying with 543.2 and 543.3, the CPC being mechanically protected, eg; within conduit

(iii) Two individual CPC's each complying with section 543. The two CPC's may be of different types eg; metallic conduit together with a cable CPC. One of the CPC's may be formed by metallic sheath , armour or wire braid within the cable.

(iv) An earth monitoring system may be installed...........

(v) Use of a double wound transformer......................


607-04-01 states:-

The cross sectional area of the protective conductors shall be not less than that determined in accordance with this section (ie: 607) or regulation 543-01, whichever is the greater.


Conclusion

In the 16th 607-02-04 should be used as the deciding factors in determining how a high integrity earth connection is arranged.

In the 17th there does not appear to be an equivalent of 607-04-01 which, as far as I can see, is the onlyt possible area which may cause some ambiguity - ie in selection of CPC csa.


Regards

 

[THRIPSTER]

Thripster,


Softus didn't miss the pre-amble - so sorry Softus.

 

[Softus]

Your answer confuses me Thripster.

I left out a lot of things from the 16th Edition, but I didn't use the omission as a device to suit my argument.

The question is: is there a contradiction?

If so, how does one resolve that contradiction, and what is the outcome of that resolution?

 

[THRIPSTER]

Softus,


I am not quite sure whether there is a contradiction but, because I cannot tell, probably means that the original regulations were not worded clearly and probably expalains the difficulties that we have seen here.

I think that the only area of ambiguity is when picking the csa of the high integrity CPC's but does attempt to clarify by saying 'whichever is the greater'. I think we can see what they meant by the fact that

607-04-01 which states:-

The cross sectional area of the protective conductors shall be not less than that determined in accordance with this section (ie: 607) or regulation 543-01, whichever is the greater.

is omitted from the 17th as far as I can see.

 

[Spark123]

A protective conductor can link an exposed conductive part to the MET, theres two independant links from each point to the MET.
Is it fair to say there are two independant protective conductors from each point to the MET?

Only if you believe that you could completely remove all of independent protective conductor #1 and be left with a normally compliant independent protective conductor #2.

If you can't remove one to leave one then you didn't have two in the first place...

OK, I have removed one of the CPCs from the top left hand socket, this now leaves one CPC complying with 543 from it to MET terminal 1. The next socket has a CPC complying with 543 connecting it, via the other sockets in the circuit to MET terminal2.

 

[NotHimAgain]

Whatever makes you think that I spend my days trying to PROVE you wrong. Do you really think you are that important.

My apologies - I must have been confused by the fact that 75% of all the posts you had made on this forum were in this topic, and that their consistent theme was not one of agreement with me..

Come on BAS that sort of misuse of statistics is beneath you.

 

[tim west]

What Bas has been trying to do is confuse the issue with the reg by denying that to have high integrity earthing you need a backup earth to the original which is what you get with a RFC if one leg gets disconnected accidently for whatever reason then the backup earth is still there. Its as simple as that, we have physical cables or wires not pretending that as they are joined together that one conductor is equal to one cable,wire.

If we had to price jobs with materials used showing quantity of cable used and put down one long cable I dont think the customer would take kindly to that.

 

[ban-all-sheds]

OK, I have removed one of the CPCs from the top left hand socket, this now leaves one CPC complying with 543 from it to MET terminal 1. The next socket has a CPC complying with 543 connecting it, via the other sockets in the circuit to MET terminal2.

Each of those cpcs complies with 543-02-09, does it....

 

[ban-all-sheds]

Come on BAS that sort of misuse of statistics is beneath you.

In what way was it a misuse?

 

[ban-all-sheds]

What Bas has been trying to do is confuse the issue with the reg by denying that to have high integrity earthing you need a backup earth to the original which is what you get with a RFC if one leg gets disconnected accidently for whatever reason then the backup earth is still there.

I'm not trying to deny, or confuse anything. That's your job - denying that the regulations call for two individual cpcs and confusing the two ends of one conductor with two conductors.

Its as simple as that

It is simple, but you've decided that "two individual protective conductors" doesn't actually mean "two individual protective conductors", and you will not listen to reason about it, nor will you accept that a conductor has two ends, nor will you answer any of the questions I've asked that involve counting conductors.

we have physical cables or wires not pretending that as they are joined together that one conductor is equal to one cable,wire.

It's not a pretence. If you take 2, 3, 4,or any number of wires and connect them together in series then you have 1 circuit conductor.

If you think that you can take 6 lengths of cable and 5 metal straps and connect them together in series so that there are two free ends and have two individual protective conductors then please indicate using Spark123's diagram where you could remove one of the two individual protective conductors leaving one remaining individual protective conductor.

 

[tim west]

Bas i've explained sufficiently throughout this thread till im blue in the face. No matter what each of us says we will beg to differ.