cpc on lighting circuits

[mark lycett]

Hi is it necessary to have a cpc on a lighting circuit when all fittings and switches are non conductive and the final circuits are RCBO protected. Its an older installation fitted when regs were different. Just wondered if they had changed. An 18th edition reference would be handy . Thanks for any replies.

 

[AndyPRK]

It doesn’t comply with 18th
But you just need a label on the Cu saying lighting cct has no cpc

 

[JohnW2]

It doesn’t comply with 18th

Indeed. The current regs simply say that a CPC must be run to 'every point' on every circuit (the only exception being a suspended lampholder).

But you just need a label on the Cu saying lighting cct has no cpc

As you imply, the requirements of 18th ed are not 'retrospective' and so there is no requirement to upgrade an existing installation to comply. Although probably sensible, I am not actually aware of any regulatory requirement for a label such as you suggest.

The one thing of which the OP needs to be aware (as he probably already is) that any new work on the lighting circuit (modification/extension etc.) would have to comply with 18th ed., so a CPC would have to be run to at least every 'point' in the new work - and some people might argue that such work might invoke a requirement for the entire circuit to be compliant with current regs.

Kind Regards, John

 

[ericmark]

The Best Practice Guide for inspecting and testing did have an example of a label but this has been removed, so getting an EICR done it is possible lack of CPC would be coded what is important for rented accommodation is it does not get code 2.

This is from BS 7671:2008 but each one says some thin similar

BS 7671:2008 Requirements for Electrical Installations was issued on 1st January 2008 and is intended to come into effect on 1st July 2008. Installations designed after 30st June 2008 are to comply with BS 7671:2008.
The Regulations apply to the design. erection and verification of electrical installations, also additions and alterations to existing installations. Existing installations that have been installed in accordance with earlier editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading.

it will be noted it is design date not installation date, so a 4 year job could still be having items installed to the earlier edition so swapping light switches to another one stipulated on the design is still allowed.

However light switches are not often marked as class II neither are ceiling roses, so although they may had the little bungs that go over screw holes, or use nylon screws and be quite safe, without the

mark on the switch or ceiling rose how does an inspector watch his back and sign it off, so one can understand the difference between potential dangerous and not complying with current regulations. There was a code 4 for not complying with current regulations but it was removed.

So no CPC was allowed before 1966 but the first BS 7671 only came out in 1992 before that it was not a British standard, so BS 7671 has never allowed no CPC to lights.

Since in 1966 there were no RCBO's the installation is clearly not as designed in 1966, yes I know with RCBO's it is safer, but it is not as designed in 1966 so any inspector could say it is non compliant. As to potential dangerous well 230 volt AC is always potential dangerous it is rather a silly phrase, I would say no it is not potential dangerous, but that is a personal opinion as is everything on an EICR, which is why the person doing the report needs professional indemnity insurance, Best Practice guide is just a guide, if he is a scheme member, then the scheme require him to follow their instructions, even if he personally feels they are daft.

I personally feel plastic and wood consumer units were fine, I had a Wylex fuse box for years and so did most houses I visited not seen a single one go on fire, but London fire brigade it seems found some had gone on fire, likely poor fitting and/or design, but knee jerk reaction was metal consumer units. As to if the move was due to BS 7671 or if there is some other law which caused the BS 7671 to include the requirement for metal consumer units I don't know, if it was not the BS 7671 but some other body that required the change, then the "not necessarily mean that they are unsafe for continued use or require upgrading." comes into play, if some building regulation or HSE rule then it may be necessary, BS 7671 may not be retrospective, and it is not law, but it follows new regulations so there may well be a new law which requires it.

So in your own house how will anyone know? Even if it is law, no CPC was OK in 1960 so why have it now? I would not worry unduly about it, but in a rented house that is a different matter, the occupants have no option as to what is done. So the owner must follow the rules, and the BS 7671 it seems in spite of saying it is not law, is to all intense and purpose it is law.

 

[mark lycett]

Thanks for the replies , its great to see how we all interpret the regs. I was thinking along the lines of chapter 13. The fundamental principles, As we know the regs aren’t set in stone so as long as an installation complies with the fundamentals of the regs then it should be allowable. I would have said that the lighting circuit in question complies fully with the above principles. I’m going to be doing the inspection and testing course after Christmas , its been 20 years since I last did it. I’m really looking forward to seeing what has changed. Thanks again.

 

[JohnW2]

However light switches are not often marked as class II neither are ceiling roses, so although they may had the little bungs that go over screw holes, or use nylon screws and be quite safe, without the

mark on the switch or ceiling rose how does an inspector watch his back and sign it off, so one can understand the difference between potential dangerous and not complying with current regulations.

If, as I presume to be the case, you are referring to 'plastic' light switches and ceiling roses, then I'm not sure what you are talking about or suggesting - you are surely not suggesting that an inspector who wished to "cover his/her back" might 'fail' every standard light switch and ceiling rose etc., are you?

I don't see what difference a "Class II" symbol on such accessories would make - provided that, in the case of a switch etc. faceplate screws going into an unearthed metal back box were nylon (ceiling roses don't usually have any 'screws', so it's not an issue). - but I suppose it brings me back to the question I often ask (but never get any reply), namely "if it's not Class II, and cannot be Class I (because it has to external metal), then what is it? - 'not allowed', perhaps?".

Nor do I see that the presence of an absence of a CPC makes any difference to the situation, other than that one does not (theoretically) have to use nylon faceplate screws for a switch if they go into an earthed backbox. As for the actual accessory, even if there is a CPC, it cannot be (functionally) connected to a plastic accessory (at most, it can be 'parked' in a supplied terminal). So, again, what do you think the situation is with, say, a ceiling rose if it is not (marked) as Class II, but doesn't have any external metal parts which can be earthed, even when a CPC is available (so that the absence of an available CPC would seem to make no difference)?

Hence .... even when there is a CPC, if an accessory does not have "the symbol" (and therefore is not Class II) and does not have any external metallic parts which could be earthed (hence cannot be Class I) then (a) 'what is it?' ('class'-wise) and (b) what difference does it make whether or not a CPC is 'available'?

Kind Regards, John

 

[ericmark]

I have metal faced class II devices, and fans which are class I and only place you can access to test earth is the metal shaft, and I had a long screw driver which I used to reach the shaft through the guard.

What I am looking at is a jobs worth inspector. I know with a light switch which has covers for screws one has to dig out the covers with a screwdriver so unlikely anyone can touch the screws. At least without a tool.

Personally a blob of silicon on the screw heads is enough. But on the other hand, to say some one is wrong to give a code C2 is not something I can do either.

If the owner has followed the rules and tested every 10 years, from 1976 they will have been aware of the problem. It should be on every PIR and EICR done.

However my parents never got one done, and I knew in 2004 that the house needed a rewire, my dad would not permit it, so was 2018 before done, so took me 14 years not 28 days.

I have problems with this house, which are also on hold, due to Cov19 so I under stand the problem, one can't snap ones fingers and rewire a house even if you have the money.

My mother was in a care home nearly 6 months and I only just finished the rewire in time, I did not start looking for a firm to do the work straight away, but most had a 3 week waiting time before they could start. So 28 days is far too short.

But if an inspector says needs a rewire I can't without being on site say no he is wrong.

 

[EFLImpudence]

I am always intrigued by this 'touching the screws' scenario.

Is it really worth considering?

The only occasion I can think of is, possibly, with a metal screwdriver but then, of course, the plastic inserts would be of no benefit - having been removed for access.

 

[JohnW2]

I have metal faced class II devices ...

Yes, and I also have a few (not many). However, as you said, accessories used on lighting circuits (switches, roses, lampholders etc.) are not marked as Class II and therefore cannot be regarded as such.

As far as I can see, the issue is not really about the (plastic) accessory, per se. In the case of a plastic ceiling rose or lampholder, when there are usually no exposed-c-ps (not even screw heads), the absence of a CPC is surely of no importance/relevance in relation to safety, is it?

As far as I can see, the only issue arises when, say, a (plastic) switch has a metal back box. As you say, if that backbox (which essentially 'becomes part of the accessory') is not earthed (because there is no CPC) then it can be said that the heads of the faceplate screws (if metal) are (non-earthed) exposed-c-ps, and therefore non compliant - but, as you say, tat can be overcome either by using non-metallic screws or by 'insulating/covering' the screw heads in some way. If the backbox itself is 'plastic' (e.g. a 'plasterboard box'), there is presumably no issue.

Kind Regards, John

 

[DetlefSchmitz]

However light switches are not often marked as class II neither are ceiling roses,

As opposed to the definition of class I and class II, the marking of things by law (European Law at the moment in our case) with class II icons only applies to appliances, so the things you are talking about will never be marked. You bring this up rather often and it is simply not an issue.

 

[JohnW2]

As opposed to the definition of class I and class II, the marking of things by law (European Law at the moment in our case) with class II icons only applies to appliances, so the things you are talking about will never be marked. ...

That might be true in law, but BS7671 appears to 'require' marking of any Class II items of 'equipment' (whatever that might include).

You bring this up rather often and it is simply not an issue.

It's not the marking that I 'keep bringing up', but the requirements for protection beyond 'basic insulation'....

... My point is that 410.3.3 appears to require that all parts of an installation have to have ("shall have") one or more of the specified protective measures in addition to 'basic insulation". If we forget the special cases of (iii) and (iv), the (i) seems to imply what we would call 'Class I' (reliant on a 'earthed' metal barrier) or (ii) (what we would call Class II). Hence, if part of an installation cannot be Class I (because there is no metal barrier to 'earth', then it presumably has to have "double or reinforced insulation"? Are you saying that you believe that the sort of accessories we are talking about are considered to have "reinforced insulation", even they do not (are not required to be) marked as such?

Kind Regards, John

 

[DetlefSchmitz]

That might be true in law, but BS7671 appears to 'require' marking of any Class II items of 'equipment' (whatever that might include).

I believe that the scope of the word 'equipment ' is not clear in this and other standards. Otherwise everything would be marked. The EU legislators take this to mean 'Appliances'. The wiring regulations want it to mean something more general. As it is so unclear, sockets and the like are not (in my experience) marked.

It's not the marking that I 'keep bringing up',

You will notice that I was addressing Eric with that comment.

 

[JohnW2]

I believe that the scope of the word 'equipment ' is not clear in this and other standards. Otherwise everything would be marked. The EU legislators take this to mean 'Appliances'. The wiring regulations want it to mean something more general. As it is so unclear, sockets and the like are not (in my experience) marked.

It's certainly true that few, if any standard 'electrical accessories' bear a Class II marking, even when it looks that they would probably 'qualify'. However, I'm not sure that the authors of BS7671 would necessarily agree that they are "so unclear" (in stating what they mean by "equipment"), given that BS7671 appears to clearly define "equipment" as encompassing virtually anything and everything comprising, or associated with, an electrical installation ...

Equipment (see Electrical equipment).
Electrical equipment (abbr: Equipment). Any item for such purposes as generation, conversion, transmission,
distribution or utilization of electrical energy, such as machines, transformers, apparatus, measuring instruments,
protective devices, wiring systems, accessories, appliances and luminaires.

You will notice that I was addressing Eric with that comment.

I confess that I didn't at the time (or, at least "didn't take it in"). However, as I said, whether there is marking or not, 410.3.3 appears to require that, for any 'electrical equipment' (presumably per above definition), in an LV part of an installation, which does not have any external metallic parts which could be earthed (to facilitate ADS) there is effectively a requirement for "double or reinforced insulation" - so, what we would normally describe as "Class II", even if there is no marking or explicit claim to that effect.

If there is 'nothing to earth' and there is nothing confirm that the insulation is "double or reinforced", I can't see how one could be confident that one was complying with 410.3.3 when using a particular product.

Kind Regards, John

 

[ericmark]

As you say not all equipment or appliances are marked, common to see a bulb holder marked double insulated but never found a bulb so marked.

I paid well over the odds for a 2D lamp with double insulated marked on it, I am sure same as those not marked at half the price in B&Q.

 

[JohnW2]

As you say not all equipment or appliances are marked, common to see a bulb holder marked double insulated but never found a bulb so marked.

Are you sure about that? How can a (standard/simple) bulb holder be regarded as having "double or reinforced insulation" as a protective measure if one can stick one's finger in and touch the potentially live contacts?

Kind Regards, John