Earthing problem

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A family member has just moved to another house (a bungalow). An electrical safety report states that there is no earth to the lighting circuit. I have removed a couple of light switches, and there is no earth conductor to either of them - I haven't checked things in the loft. Getting an earth cable into the loft to the individual light fittings is no great problem, but getting one to the switches looks to be physically impossible - short of chasing a new channel in the walls. As the light switches are plastic, it seems to me that the only possible hazard arises from the screws that attach them to the metal boxes in the wall. Does anyone know if replacing all the switches with 'screwless' ones - as well as, of course, running an earth conductor to the light fittings themselves, via the loft - would comply with the regulations?
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Hi No shortcuts with mains electricity I'm afraid the earth is for a reason.(eg you are moving a new table into the house as it passes end on through a doorway it smashes the light switch crushing the live feed against the metal back box ,unaware you bringing up the rear rub against the now exposed metal box SHOCKING.) My advise FWIW is have a complete electrical survey done on the property by an approved NICEIC contractor as if the lighting has no earth the power may be only spurs not ring mains ,,,,,,and so it goes on. Sorry to be a killjoy but after 35yrs in the game I have seen some death traps waiting to spring on newly acquired property owners. IIR a sold property these days should have an electrical safety cert' as part of the sale?? other on group may be up to date on this.
HTH CJ

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Very unlikely and also very unlikely to kill anyone.

The OPs relative has had an electrical report done. It says that there is no cpc on the lighting circuits.

Even if the electrical report says that the electrics are a death trap it does not stop someone buying that house.
Adam
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You are not being a 'killjoy' - just patronising and self-important! Actually, I spent a deal more than 35 years in the 'game' - that is, the electrical business - albeit not domestic electrical installations, but something a deal more complex. I asked the question because I'm not up to date on present regulations - not because I wanted a lecture on safety, I'm all too aware of the need for that.
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Steady on - that's unwarranted. There is no reason to suppose cj knows your background, and with comments like "my advice FWIW", "IIRC", and "others may be up to date" he couldn't have been much more gentle and modest.
See current thread on "lightbulb not switching off" if you need persuading that not everyone here has had "35 years on the game".
Re. your problem, it might be worth looking closely at the possibility of using existing cable drops to pull through new T+E. I've recently done similar, to replace twin with 3-core for 2 way. Was surprisingly straightforward.
--
Martin




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Ok, fair enough - and thanks. Perhaps I did bite a bit too much. Having said that, there is a tendency on here for some people to respond in a world-weary, patronising way. Just because you don't know anything about someone else's background, that is no justification for making unwarranted assumptions, or adopting a patronising tone.
BTW (and on a lighter note), I do hope that very few here have had 35 years *on* the game - I wouldn't want to move in those kind of circles!
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Farmer Giles wrote:

FWIW I haven't had 35 years on the game, _whatever_ game it is. I only commented on the lightbulb one to try and stop the guy killing himself. but WTF. It's only evolution in action :/
Andy
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I was not being patronising or self important just trying to be of help to someone I have never met who asked a question on a DIY news site.Not a technical bulletin board for electrical engineers. My recommendations were based on your post which stated 'An electrical safety report' .This was not specific and having seem many so called reports wrongly ( i accept) assumed you may not have had a legitimate document. I respect Adam's comments but stand by my post as I did not mention death just the possibility of a shock .(There have been numerous post on this NG in the past regarding shocks from newly plastered or papered walls where switches were left loose and my example,however remote, is plausible.) My intent was to warn you of the possible dangers in simple terms and provide a possible solution.
So at the risk of again being insulted I offer this, Check the switch boxes to see if the cabling is in capping or tube (it should be). If so rewiring can sometimes be achieved by using the existing cable as a draw wire. If loft access is easy you can sometimes see the capping protruding from the ceiling below. Nylon screws 3.5mm are a rarity (you can buy them but they come in 1000 for 22 aprox' bags RS Components IIR) Try a diy store in the Plumbing isle look for bathroom fan switch bolts or your local hobby/model shop may stock them.(used on some nitro cars) also used on door entry systems and nurse call wall plates.

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Is see RS do bags of 100 nylon screws for about 5 or 6 quid. Thanks for the info as I do need some.
I would suggest nylon screws are the way forward for the OP if wants to make the lightswitch safer. Even a bag of a 1000 screws at 22 is cheaper and easier than changing the back boxes. I have often found that changing the old wooden back boxes to metal ones cannot always be done without causing some damage to the surrounding area and needs a finger plate surround to cover the damage.
Do you remember the old metal back boxes with the plastic lugs? Mid 1960s installs at a guess..
A rewire of the switch drops on a room by room basis as they are decorated is also recommended.
Adam
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Sure do found many with 1" x 6 woodscrews instead of the correct screws (then IIR were was it 2BA?) . Wooden back boxes!! days of (was it 1/2") rolled tube conduit and a massive hole if you tried to get them out.We used to carefully split the sides allowing a new metal box to be fitted over them.Then came the days of earth integrity and all the old conduits had to be cross bonded.(yeh ! like that got done in every rewire). On the note of the in wall wire stripper a trick we learned was to chip out a little plaster above the box exposing the capping,then gently bend it outwards forming a lip,this averted the problem and acted as a guide for the new cabling. Happy days CJ

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Good point. Although is was 4BA
Note to Farmer Giles
You may find that your screws are not 3.5M but 4BA.
Adam
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1 - There is no requirement to u/g existing wiring to current regs. - If the electrical install is safe, that is all that is required.
I would not be happy with Class-1 metal backboxes without a CPC. As suggested use a M3.5 nylon screw or see #3 below.
2 - NICEIC etc do a PDF about light circuits without CPC - States WR & BR are not retrospective - States lighting circuits should have Class-II switch/fittings
3 - Class-II FLUSH PVC backboxes do exist - MK EGA, MK ESU/9/ML - They are very hard to get hold of, but do exist - Direct substitute for metal backbox
4 - When each room is redecorated fit oval conduit drops - It is then a simple matter of a cable down a tube "forever"
5 - Check the loft for spare wallpaper, you never know
You can convert each light drop to oval & new CPC cable: - Power off - Cut the wallpaper-only 1in wide in the middle - Peel back the wallpaper to ceiling - Cut a 16mm slot thro the plaster - Fit in the oval conduit - Plaster not quite flush to hold, let it go off - Plaster flush using a 1" scraper to level perfectly - Use a piece of 1" wide D-Flat wood to cover - Paint to match the wallpaper accordingly
Some people run the D-Flat wood to the floor or even use a 1G width version. Done right it will fit in quite well as "part of the fabric".
Wickes co uk do D-Flat wood right up to very wide - something like 110x6mm, Perfect to "architrave" a wall, not so pricey.
When you redecorate you simply remove the D-Flat wood. It gives you a migration path rather than "destruction path".
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Superb reply, many thanks. I think that the approach that I will adopt is to make absolutely sure that the installation is safe, in the first instance - check that everything is class II, fit nylon screws, etc - then rewire each of the drops as each room is redecorated. Because my relative (my son, actually) has only recently moved into the property - and it does need to be, and will be, redecorated throughout - that would seem to be the best way to proceed. Because the loft of the bungalow is fairly spacious and accessable, I think that I'll run new twin and earth to the light fittings, rather than just a cpc - would it be permissable for me to do that under Part P? It's not a big property, with no more than 10 light fittings, so would 1mm cable be acceptable, or would you recommend 1.5mm?
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Prudent and simple.

Yes, even in a Bathroom or Kitchen if via the same route. The ODPM document says "circuit" and circuit is defined under BS7671 as that protected by a Circuit Protective Device (fuse, MCB, RCBO). Plus in any case you are doing this progressively over time, and thus each part is considered separate.
What I would do is... - Replace the supply cabling to each ceiling rose now - Replace the ceiling rose where necessary
I say that because you may find the cable is degraded through overheated connections, junction boxes in the loft, or poor strain relief on dated ceiling roses, or lack of high temperature cable for ceiling rose drops. Lots of things get skimped over the decades re ignorance or simply predating current regulations.
No-one is going to complain about improving safety, but make sure it is improved :-) With regard to that, do not overtighten screw terminals on FTE 1.5mm cable - the CPC is still 1.0mm which is easily "bissected then snaps when flexed". TLC does the temperature resistant cable drops from ceiling roses.
Technically to comply with Part L a %age of your ceiling roses should make mandatory fluorescent light bulbs, ie, the 4-pin PL type. Those fittings tend to be very expensive (I think MK were 18 at one point) which is just racketeering.
Check carefully any dimmers, some old ones were not of a particularly good design. MK can be had cheaply on Ebay if you look around and check feedback.

If the cable is *surrounded* in insulation you need to use 1.5mm 6242BH BS7211 (XLPE), Screwfix sell this (Prysmian cable). This cable is hard to work with re bending & stripping.
In most instances cable is *contacting joists or ceiling on one side* so you can use 1.0mm 6242YH (PVC), Screwfix and anywhere else sells standard PVC stuff.
Personally I would use 1.5mm as it is more robust for not a lot more money.
If the loft has not got 220mm+ or whatever insulation in it, book it in before next winter (or the summer re bake-thro :-)
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wrote:

Technically to comply with Part L a %age of your ceiling roses should make mandatory fluorescent light bulbs, ie, the 4-pin PL type. Those fittings tend to be very expensive (I think MK were 18 at one point) which is just racketeering.
Does Part L apply on a rewire?
Cheers
Adam
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wrote:

Dunno... actually it probably does to a Rewire. However this is not a rewire, it is a progressive repair.
I do not believe those special fittings are necessary - they are not particularly reliable, very expensive and money could be better spent on better bulbs or an extra smoke alarm :-)
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Part P document, SI2006.
p7 - When not necessary to involve building control bodies. b. The proposed electrical installation work is non-notifiable work of the type described in Table 1 and does not include the provision of a new circuit (see schedule 2B of the Regulations).
--- "of the type" is a broad catch-all for any basic maintenance. --- basically you can't add a new circuit.
p8 - Replacing the cable for a single circuit only, where damaged, for example, by fire, rodent or impact.
--- BS7671 16th p19 defines circuit as "an assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s)." --- so no problem replacing cables in one go, or progressively as you redecorate each room.
You can replace any cable, even in a kitchen or bathroom or across a garden (SWA). That also means you can replace some previous bodge of FTE through conduit across a garden with SWA, and also upgrade a found-to-be inadequate cable such as 4mm to a standalone cooker that someone skimped on or ignored.
Garages & sheds are not special locations once inside.
p7 - Additional notes b. Replacement, repair and maintenance jobs are generally not notifiable, even if carried out in a kitchen or special location or associated with a special installation.
You can replace any enclosure, be it a backbox in a kitchen thro steam damage (kettle, solid brick wall) to a consumer unit box. You can not however install new final circuits.
Someday I will break SI2006 by moving the hall lights onto the smoke alarm circuit. The hall lights are currently wired on the upstairs lighting circuit, so if the hall incandescent blows you lose the upstairs lights and can not see to get downstairs (due to window position & curtains downstairs). I dislike emergency lighting as they always tend to overheat (brown casing, even Legrand) & fail on me when needed. Since the smoke is RCBO protected the hall lights on the same circuit is a better indication of a tripped RCBO.
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Thanks, I'll check that out. Probably be trickier to locate if that's the case.
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It is probably time to bite the bullet and rewire the lights. Do the switch drops room by room if needed.
However, using class II fittings and switches will help make things safer.
<http://www.niceic.com/inc/file-get.asp?FILE=BPG1_aug07.pdf&RURL=/en/contractor/section.asp ||13>
probably gives you most of the info you want.
Adam
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<http://www.niceic.com/inc/file-get.asp?FILE=BPG1_aug07.pdf&RURL=/en/contractor/section.asp ||13>
One question should occur - do any of the light fittings need an earth, i.e. any metal fittings or fluorescents? If not and they are only fed on two core, why worry?
--
Woody

harrogate three at ntlworld dot com
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