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Old 3rd Jan 2023, 8:28 pm   #1
duncanlowe
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Default Every day is a schoolday. House lighting circuits from the past.

I hope this is an OK post, as it's regarding house lighting circuits from the 1960s, and how we relate to them today.

A few days ago I was asked about refitting a ceiling rose and pendant, after a ceiling had been repaired. The person doing the repair had removed the ceiling rose, but after the repair had said they were not allowed to refit it. That's not the subject of this post, but what I was asked to look at.

I've attached a photo taken after the rose was unscrewed, but before it was disconnected. It's not pretty, but my spidey senses went all tingly as I couldn't see any CPC (earth) conductor. Has someone simply cut them off? Or what? So this is where I learned something new that it might be worth sharing. It seems that until 1966, there was no requirement to have the CPC in lighting circuits. And there is no requirement to upgrade them even when replacing a consumer unit. Now while this house was completed in 1967, it could easily be on the crossover. When I discussed the lack of CPC with the house owner, they had been made aware of it already.

The only issue really then was my lack of knowledge, and the fact that someone had done some work, then walked away leaving the house owner and their daughter (who's room it is) with no lights and no way forward.
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Old 3rd Jan 2023, 8:39 pm   #2
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Default Re: Every day is a schoolday. House lighting circuits from the past.

This was standard at the time. My parents had a late 1960s flat which was wired in the same way. There was even a website I used, which specialised in selling only double insulated light fittings for people who lived in similar homes. Google DOUBLE INSULATED LIGHT FITTINGS to see how many companies are catering for this niche market!

I see from your pics that the wires are twisted rather than single strand, and may be “singles” rather than twin. Again, how things used to be done at the time.

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Old 3rd Jan 2023, 8:40 pm   #3
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Default Re: Every day is a schoolday. House lighting circuits from the past.

In my limite experience, I've never seen an earth on a ceiling light fitting here in Spain. All the dangling lampholders I have seen were either bakelite (older ones) or plastic (modern), so there's nothing to actually earth. Just the two core flex going to the bulb.

Obviously, if you had a more elaborate metal assembly, the kind with spot lamps or something on, it would be necessary.
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Old 3rd Jan 2023, 8:44 pm   #4
Dennis M
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Now that you have found that there is no CPC you ought to fit a warning label to the board to try and stop anyone from fitting a metal fitting to that circuit.
Out of interest has any work been done to the electrics in recent years ?
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Old 3rd Jan 2023, 8:45 pm   #5
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Default Re: Every day is a schoolday. House lighting circuits from the past.

When I moved into this house, all the lighting was run in double sheathed singles, as was indeed the norm, no earths. The only light fitting with exposed metalwork had been installed later and a separate earth run to it.
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Old 3rd Jan 2023, 9:03 pm   #6
Roger Ramjet
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Hi Duncan,

I am an ex electrician 14th then 16th edition. My house has exactly the same wiring which was the norm at the time it was built.

It's not a big deal providing you are not fitting a new light that requires an earth connection. A neighbor once asked me to swap out a bathroom fitting for a metal one but I politely declined.

Your switch drops are of more concern because they won't have protective earths either. Once again not great cause for concern a unless an attempt is made to swap them out for metal ones that require an earth connection.

Common sense should have prevailed with the repair & I seen no safety issue in fitting a standard [non metal] ceiling rose & lamp holder.

Rog

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Old 3rd Jan 2023, 9:14 pm   #7
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Yes, the back boxes for the switches won't be earthed, or then again, they might be wood (which is deprecated beause it's flammable), see picture (found online).

When my parents owned the aforementioned flat, ISTR filling the switches' securing screws' recesses with some kind of plasticy filler to lessen the risk of shock.
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Old 3rd Jan 2023, 9:22 pm   #8
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Answering a couple of questions.

It may well have been singles. I can only comment on what had been left sticking through the ceiling.

But in another situation 30+ years ago I did find that you could get 2.5mm twin without an earth. Some but not all sockets had a 0.5mm flex earth added. That got rewired in short order. In this circumstance my guess is it was twin, as the switched live back from the switch was black. Familiar to me but I know has confused many people back in the day.

Yes, work has been done (not by me) in fairly recent times. The house owner had been made aware of the situation and was not concerned, and it seems from the conversation the person replacing the CU knew their stuff. I asked about a label on the CU and there wasn't one according to the house owner. Given that I'm hoping the various metal luminaires on the downstairs circuit are either the right class (class 2?) or the downstairs circuit is different.

I agree, the cable is multicore not solid. I have seen that before on my parents old house of a similar age. But on that the CPC was present. A different oddity I did see there was that there was twin and earth where both conductors had red insulation down to the switch and back. Makes sense and wouldn't have been a problem if the original installation hadn't fed some parts of the rest of the house from the permanent live side of the kitchen light switch. Ended up swapped to the switched live side meaning those lights only worked when the kitchen light was on.
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Old 3rd Jan 2023, 9:32 pm   #9
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Default Re: Every day is a schoolday. House lighting circuits from the past.

And thanks for the other feedback that has come in during my last post. I think common sense has prevailed and a new but entirely insulated ceiling rose and lampholder has been fitted. BTW is anyone interested in a 1960s Ashley rose and lampholder that is now surplus to requirements? In the condition you might expect from mid sixties fittings is my understanding.

It seems that many people already knew about this, but still think it might have been of use to others. As I said, it was all new to me even though I'd worked (as a DIYer) on house wiring many years ago on my parents house and then my own houses.
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Old 3rd Jan 2023, 9:50 pm   #10
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Default Re: Every day is a schoolday. House lighting circuits from the past.

This guidance should cover the situation but needs to be read carefully as otherwise it could appear contradictory, especially in Section 4. https://www.electricalsafetyfirst.or...-1-issue-3.pdf

Section 10 gives guidance on situations like this one, with reference to lighting circuits.

Although Section 4.2 states

"BS 7671 does not require existing circuits to be upgraded to current standards in order for them to be connected to the outgoing ways of the replacement consumer unit"

the guidance then goes on to state at 4.4

"Where a consumer unit is being replaced, additional protection by means of RCDs in accordance with Regulation 415.1 must be provided to the extent required by the current edition of BS 7671, as amended, such as for: socket-outlets (Regulation 411.3.3)
• mobile equipment for use outdoors (Regulation 411.3.3)
• cables concealed in floors, ceilings, walls or partitions (Regulations 522.6.201 to 203 as appropriate)
• low voltage circuits serving a location containing a bath or a shower or
passing through the zones of the location ( (Regulation 701.411.3.3)".

To comply with the current regulations (BS7671, 18th Edition, Amendment 2:2022), all domestic lighting circuits need to be RCD protected (411.3.4 Within domestic (household) premises,additional protection by an RCD with rated residual operating current not exceeding 30mA shall be provided for AC final circuits supplying luminaires).

I take this to mean that, if circuits are not covered by these instances where RCDs are not required by current regulations, it would be all right to reconnect them, but otherwise they neeed to be brought up to the current standard.

Since the replacement of a consumer unit is notifiable under English Building regulations consent is needed unless the change is done by a registered person who has to issue an Electrical Installation Certificate.

The way that hanging ceiling rose has been wired doesn't inspire much confidence - too much bare copper and it looks like it's damaged.

A lot has changed since 1966 in terms of safety standards and there's been nearly 60 years for the installation to deteriorate, so the householder needs to be aware of this and it would certainly be advisable to fully assess the condition of the rest of the installation and be prepared to justify any decision to the insurers.

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Old 3rd Jan 2023, 10:28 pm   #11
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Yes. If it was me or my house I would not be happy and would have had the wiring renewed. Never mind the lack of a CPC, there's a lot of risk of even PVC insulation having deteriorated. Back in those days it wasn't uncommon to use polystyrene beads as loft insulation and we all know what that can do to PVC cable.

It's not my installation. From what I understand the house now has a new CU with RCD's on all circuits, but I haven't seen the CU. I was told that it has been reviewed recently and deemed safe. I'm not qualified to comment. It's just that what I saw in the photo surprised me until I did the digging. And replies have confirmed it's quite common.

Regarding the rose: after the installation of the new rose, I've been given the old one as it's vintage and maybe of interest here. The base is cracked. The screw for the loop in is missing too (which it wasn't when removed). The pendant flex was actually three core (new colours) with the CPC cut off, and the secondary insulation terminating outside the lamp holder. TBF it will most likely be going in the bin quite soon!
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Old 3rd Jan 2023, 10:52 pm   #12
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Default Re: Every day is a schoolday. House lighting circuits from the past.

One thing that occasionally crops up in mid 60s houses. The fact is the lightning circuits are wired in twin and earth cable but as they were wired before the requirement for earth came into force the earth wire is simply not connected or cut off. Infact there is a whole housing estate near me wired by the Southern Electric Board and at the time no earth wires on the lighting circuits were connected.
Hence never use a earth without testing its continuity.

In your picture I would make the connections a bit better and the switch return should have some red or brown sleeving on it . It’s not a problem with no earth unless you are replacing the rose with a metal fitting .Andy
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Old 3rd Jan 2023, 11:00 pm   #13
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Just looking at the picture. Double check and make sure there is not a earth In The outer insulation just cut off.
The cable is bare copper so normally that’s the later part of the 60s early part of the 60s is normally tin plated copper . Andy
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Old 3rd Jan 2023, 11:49 pm   #14
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Metal flush back boxes for non earthed lighting circuits were available at the time with nylon threaded inserts for the switchplate fixing screws. Thus no risk of the screws going live if any bare wire touched the backbox
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Old 4th Jan 2023, 12:29 am   #15
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Last year I had an EICR (electrical inspection) done on our house in Cambridge by a reputable firm. The issue of non-earthed lighting circuits came up. The wiring in that house is something of a patchwork, though I've tried to keep it all up to scratch. The electrician was surprised and delighted to find that the metal light fittings in the living room were actually earthed - he was expecting them not to be! Checking that non-double-insulated light fittings have a good earth is a routine part of the EICR. If there's no earth, the fitting must be double insulated. This is considered quite normal and perfectly acceptable.

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Old 4th Jan 2023, 2:34 pm   #16
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Default Re: Every day is a schoolday. House lighting circuits from the past.

I am no electrician and thus my knowledge is near zip but considering that LED lights are now the norm and to make these work in traditional installations each lamp requires a PSU to step down to the LT required to run the LED, and on the basis that all lamps in the house would be LED, is the way forward to have lighting circuits run at LT from a step-down PSU supplying 20v or 40v or whatever it is from the consumer unit? And perhaps, in practice, this circuit would only need to be twin cable?

We are now a long way from 100 and 150w incandescent bulbs and if every light in the house was switched on the circuit might be pulling a kilowatt or more.

It seems to me to have a house of LT lamps operating off a 230v circuit is now ass-about-face.

Or am I missing something? (Or several things?)
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Old 4th Jan 2023, 2:39 pm   #17
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Default Re: Every day is a schoolday. House lighting circuits from the past.

I don't think you're missing anything, but this would be unconventional at present, and could cause a lot of confusion unless you did it exclusively for your own personal use.

Don't forget that wires have to be thicker to deliver the same power at a lower voltage, though I appreciate that the far greater efficiency of LED lamps counterbalances this to a large extent.
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Old 4th Jan 2023, 2:54 pm   #18
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Quote:
Originally Posted by McMurdo View Post
Metal flush back boxes for non earthed lighting circuits were available at the time with nylon threaded inserts for the switchplate fixing screws. Thus no risk of the screws going live if any bare wire touched the backbox
Yes I had a few like that here on things where no earth was provided; the nylon threaded things had embrittled with age and crumbled away to frass when I tried to unscrew them.

Metal back-boxes fitted as a replacement, and the new switches came with small white nylon top-hat-shaped 'bungs' to fit in the recesses where the screw-heads would otherwise have been accessible. So everything is still nicely insulated.
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Old 4th Jan 2023, 3:17 pm   #19
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Quote:
Originally Posted by Nickthedentist View Post
Quote:
Originally Posted by Junk Box Nick View Post
I am no electrician and thus my knowledge is near zip but considering that LED lights are now the norm and to make these work in traditional installations each lamp requires a PSU to step down to the LT required to run the LED, and on the basis that all lamps in the house would be LED, is the way forward to have lighting circuits run at LT from a step-down PSU supplying 20v or 40v or whatever it is from the consumer unit? And perhaps, in practice, this circuit would only need to be twin cable?

...
I don't think you're missing anything, but this would be unconventional at present, and could cause a lot of confusion unless you did it exclusively for your own personal use.
LEDs, by their very nature, need some local electronics to drive them anyway, just like fluorescent tubes and other discharge lamps do. I think therefore there's relatively little to be gained by changing the supply voltage to them. It would just need slightly different electronics at each fitting. There's also the issue that different types of fitting will need different supply voltages and currents: a spotlight might have, for optical reasons, just one powerful LED driven at an amp or more with a forward voltage of about 3.5V, whereas a ceiling light panel like the ones in my office will probably give best results with several dozen small LEDs spread over its area, and the most efficient way to run them is to connect them in series and drive them at low current but high voltage.

It's no harder, really, to drive either of these from 230V than it would be from, say, 12V.

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Old 4th Jan 2023, 3:22 pm   #20
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Default Re: Every day is a schoolday. House lighting circuits from the past.

Quote:
Originally Posted by Nickthedentist View Post
I don't think you're missing anything, but this would be unconventional at present, and could cause a lot of confusion unless you did it exclusively for your own personal use.

Don't forget that wires have to be thicker to deliver the same power at a lower voltage, though I appreciate that the far greater efficiency of LED lamps counterbalances this to a large extent.
When you consider it, our entire housing stock is pretty much operating on a legacy system necessary to operate obsolete incandescent bulbs that lasted for nearly a century after gas mantles were superseded but it seems to me that new housing stock could be built with an LT circuit. Obviously a different standard of connections and fitting would be required to distinguish the system from the traditional for safety reasons, etc.

Save the flourescent lamp in the garage which will have to go when it fails as it is obsolete (I am out of spare tubes) my house operates entirely on LEDs. I didn’t like the earlier low energy bulbs as they always seemed dimmer than the incandescent output they claimed to replace – never mind the annoying time taken before they got to full brightness but the current (no pun intended) crop of LED bulbs are superb. I seem to have brighter light from an equivalent rated LED than from a 100w incandescent and in some rooms with a couple of fittings have decided replace with lower ratings as it is a bit like being under floodlights!

Agreed, for the same power output the current at a lower voltage will be greater but this leads me to wonder how much the actual LED is drawing from its internal PSU.
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