Earthing :S

[telectrix]

At least a 2 - requires improvement.

It should also be pointed out that automatically declaring an installation with a category 2 deviation "Unsatisfactory" is an NICEIC and NOT an IET requirement.

if, as you say, a code 2 is " requires improvement" but can still be deemed as satisfactory, then i've no argument with that.

 

[ChristianG]

I thought all fixed wiring must have a CPC along the length of the installation?

On a lighting circuit, isn't there potential for a patrice screw on a switch to become live for instance from a loose live?

Still so much to learn and i want to do the 2391 in a few weeks ARGHHHH!

 

[topquark]

I thought all fixed wiring must have a CPC along the length of the installation?

To be up to current regs, yes. This is for existing installations, in the common case a lighting circuit with no cpc, as long as there are no accessories requiring an earth (ie metal) then it's acceptable, just not up to current regs.

 

[ChristianG]

sorry for the late edit

 

[topquark]

I thought all fixed wiring must have a CPC along the length of the installation?

On a lighting circuit, isn't there potential for a patrice screw on a switch to become live for instance from a loose live?

Still so much to learn and i want to do the 2391 in a few weeks ARGHHHH!

Yep, if it's old enough to not have been installed with a cpc then it'll most likely have a metal knockout box, so should be earthed.

 

[topquark]

Yep, if it's old enough to not have been installed with a cpc then it'll most likely have a metal knockout box, so should be earthed.

If the accessory switch has an earth to it, no need to earth the back box as the accessory screws are deemed to earth the back box. Not correct IMHO, but hey ho.

 

[msec]

[QUOTEIf the accessory switch has an earth to it, no need to earth the back box as the accessory screws are deemed to earth the back box. Not correct IMHO, but hey ho. ][/QUOTE]

Provided there is at least one fixed lug on the backbox. Agreed though, I always install a flying lead between accessory and backbox.

Going back to the OP, he seems to be getting confused between circuit cpc's and main and supplementary bonding IMO.

 

[Deleted member 26818]

Regardless what the "Best Practice Guide" from the ESC states I will never attribute a category 4 deviation to a circuit with no cpc. The Wiring Regulations make no mention of their label for an unearthed lighting circuit so it is their policy rather than the JPEL/64's.

The advice given in the best practice guide is a departure, which as per Regulation 120.3 is allowed, only if the resulting degree of safety of the installation is not less than would be achieved by compliance with the Regulations.

 

[Risteard]

The advice given in the best practice guide is a departure, which as per Regulation 120.3 is allowed, only if the resulting degree of safety of the installation is not less than would be achieved by compliance with the Regulations.

I know, but find it hard to justify the view that it affords the same degree of safety as compliance with BS 7671.

 

[Deleted member 26818]

The RCD should provide a greater degree of earth fault protection than that which would be provided by a CPC, and the OPD will provide the same level of overload protection.

 

[Risteard]

Don't agree because the RCD will only operate once leakage to earth occurs, e.g. by direct or indirect contact (to use a 16th Edition term). The cpc would disconnect before a person came into contact with it (ignoring a TT system which may not allow sufficient current to flow to operate the protective device on an earth fault).

Normally protection by double or reinforced insulation would not be appropriate only under the supervision of an ordinary person.

 

[Deleted member 26818]

Yes, I agree, if thre was a CPC, and an earth fault occured, the CPD would operate before a person came into contact with the fault.
However if as the ESC all the accessories and fittings were plastic, and there were no exposed-conductive-parts, there would be no earth fault for the CPC to disconnect from.

 

[JamesBrownLive]

At least a 2 - requires improvement.

It should also be pointed out that automatically declaring an installation with a category 2 deviation "Unsatisfactory" is an NICEIC and NOT an IET requirement.

You say that, but that is also the line taken by the ESC, and they say as much in their latest guide...

http://www.esc.org.uk/fileadmin/user_upload/documents/industry/best_practice/BPG4_08.pdf

:smilewinkgrin:

 

[Risteard]

You say that, but that is also the line taken by the ESC, and they say as much in their latest guide...

http://www.esc.org.uk/fileadmin/user_upload/documents/industry/best_practice/BPG4_08.pdf

:smilewinkgrin:

Are you aware that the NIC and ESC are blood relatives?

Also look at Guidance Note 3 which only states that a category 1 Observation must result in an Unsatisfactory assessment and that it is otherwise at the discretion of the Inspector.

 

[JamesBrownLive]

Are you aware that the NIC and ESC are blood relatives?

I didn't but I do now :dead:

Also look at Guidance Note 3 which only states that a category 1 Observation must result in an Unsatisfactory assessment and that it is otherwise at the discretion of the Inspector.

I wish there was just one governing body and one body only that could lay down just what is acceptable and what's not.
Being new to the trade I can't tell you how fustrating it is to think you are doing something the proper way only to find out you're not. I'm not talking about PIRs, or should I say EICRs :yawn:, as I know I am not competant to carry them out, but just in general.

Cheers