Twin & Earth Cables
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- čas přidán 17. 07. 2024
- Various types of twin & earth wiring cables, both modern and a selection of older types. This is the most common type of wiring used in homes and smaller commercial installations in the UK.
The older black and red insulation colours were used up to 2006, blue and brown since then.
Website: xo4.uk/?T2E
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Contact info, sending stuff in etc.: xo4.uk/?YTT - Věda a technologie
The white low smoke cable is also specified for houses formed from polystyrene ICF walls (with concrete poured in) - because the polystyrene attacks the std grey cable (same reason mains cables are packed in plastic bags in boxes with polystyrene)
Tinned copper was used originally with rubber insulation, as copper reacts with runner badly, causing the rubber to disintegrate within months. Stayed with the change to PVC insulation until the additive added was changed to stop the reaction with copper. Of course the additive was BPA, which eventually drips off in green liquid.
BTW copper coated aluminium wire is very common now in cheap cords, as it is cheaper than copper, even in cords with 3 strands inside. Used in the windings of every new motor these days, and the windings in your microwave over as well. Your scrap yards now check all enamelled wire coming in to sort this out into the aluminium scrap pile.
Been bulk watching your video backlog, excellent info videos.
Useful in this one was the date of 1966 for earth in lighting. We thought our house was built 69-71 but looking to install a metal fronted switch the other day found out we lack an earth. Sadly it's also the case in the ceiling roses and that didn't stop the previous owner fitting metal light fittings in all the rooms, even movable spotlights!
Roll on an extension next year and now planning a complete rewire..
A clear & concise explanation. I have been through 5 decades of wiring & the rewire of my house in the mid eighties. This really helped me this evening. Thank you.
Old colours were better keep up the good work, thank you for sharing.
I agree preferred when live was red stood out for warning.
There are very few people on CZcams who make videos that you find yourself watching for ages even if you're not involved in the subject. Roger Barnes is one chap who makes videos about sailing a small traditional boat - I've never sailed in my life yet I find him compulsive viewing. Today i discovered John Ward after a passing question about wiring in my workshop. Here I am two hours later watching John Ward videos simply because John Ward! And I think I've learned more about wiring in those couple of hours than I ever picked up before. Thank you very much!
another good break down and very well explained video ...thanks for sharing your skill and knowledge. ..
Hey John nice video. I was told at college the white sheathing was used in the south for its better UV resistance. Thanks for videos.
@Ian Mangham That's not for you to know.
"Made my the devil himself" laughed my head off
You guys (in the UK) were seriously ahead of my previous home (in America), which had knob and tube wiring, and earthed outlets were extremely uncommon. They didnt even have rubber insulation, it was mostly a rope-type material over the wires.
+Luke Den Hartog K&T has the advantage that it was done back in the day when people had pride in their workmanship so it's usually well installed :)
Mine still worked to this day without any issues, so I guess it worked (aside from everything in the house using a switchmode supply giving you a tingle)
that is until somebody cuts into it and reverses the polarity and wires it to a 3 prong plug.........
Good video, very informative. I recently rewired a farm house with lead sheathed cables that an older sparks told me was called "Paper lead" and he said it was obsolete prior to WWII! The insulation had crumbled to powder - I believe the conductors were originally wrapped with paper tape and talc. There is a lot of scary stuff out there especially in rural areas.
Our terraced house built in 1880 still had lead sheathed cables when we bought it in 1989, also little metal junction boxes that used to spark if you moved them! The incoming supply was also two cores in some kind of woven fabric - it was changed quickly one morning when it started to burn like a fuse working its way to the house. Happy days 🙂
Thanks John for sharing your knowledge, I find this all really interesting considering I have been a joiner for many years and have worked alongside electricians who for whatever reason just wouldn't explain anything to me about electrics.
He sounds like an airplane pilot, announcing the weather at your destination and what time you should arrive etc.
I'm literally waiting for him to say wishing you a pleasant flight !!
Yes would agree I was actually thinking about that several videos back I found enough to know the phone a few times a year at least for many years and almost expecting the airline Chimes to be playing in the background here and Aaron video as well.
And by the way the meeting of those chimes varies from airline to Airline so if it means one thing if you're on one Airline and may not mean the same on the other to put out the rest people keep asking that and wondering all the time.
Also imma dyr that does things to code and I words to byr that knows the trade and jack of all trades that knows the trade although I know my limits and wouldn't do anything I wasn't comfortable doing as well you have to know your limits with certain types of projects in terms of safety and otherwise and legality in some cases it helps to know the regs and codes beforehand also I would never slap something together that should not be done and if I run into things that are not white I like whoever or no that something needs to be done especially if things were extremely dangerous also I Maddie why are that does things to code enough words to be why I are that knows the trade and Jack wall trains that knows to trade although I know my limits and one do anything I wasn't comfortable doing as well you have to know your limits with certain types of projects intercept safety and otherwise and legality in some cases it helps to know the rags and codes beforehand also I would never slept something together that should not be done in and if I run into things that are not white I might whoever know that something needs to be done especially if things are extremely dangerous which I have on acrossed numerous times there's some things I don't even touch when I see it
One of the things I always check if there is any fuses in the system first bypassed fuses such as wire going between a fuse and hot second pennies behind Edison screw base fuses and yes seen it plenty of times.
Also occasionally I run across this but not very often with cartridge fuses let's just call them battle short fuses military term I know but I'm not military but I know what they are they had a specific purpose look up battleshort you'll see what I'm talking about Wikipedia let you know that.
But what I'm referring to is battleshort fuses in this case would be a conductive objects Jeremy light tubing or other things shoved into a fuse holder that's around about the same size and shape as the said fuse.
Also including what people would call widow-makers Aka a rifle cartridge in a fuse holder and in the case of small fuses such as the glass or ceramic 1in 1/4 inch by quarter inch fuse a 22 cartridge.
I know Jhene Sarah's are going to say if there was an overload it would just damage to wiring nothing would happen with the rifle cartridge well not the case saw the aftermath of rifle cartridge then uses a fuse on severe overload once.
It was unknown to the people that stayed there that that was in the fuse box.
Kablooey basically there was fragments of everything everywhere.
Gerald Lee where I've seen the Widowmaker would be the 22 cartridge in a glass fuse holder in a piece of equipment or Automotive or something like that.
Also I've heard people joke about that bass. Battleshort ears as well and yes people in military into doing that in a pinch.
But of course not telling anyone.
Some even have used a spent cartridge as well.
I've just been told this by others so can't substantiate and sometimes they just laughed and said oh what we call battleshort is what you might call Widowmaker joking myself so some of it's probably serious probably so it's not hard to say though.
Also with the copper clad wire we have that here in the states as well AKA United States of America United We stand and all that jazz but right now not so much on freedoms constitutional rights imbalance of power if you know what I'm talkin about I was reluctant to say this but it needs to be said!!!!
Comment if you have any comments to make will read them may reply.
@@aaronbrandenburg2441 what?
Nice video, thanks for sharing your archaeological discoveries.
An old house we lived in, back in the 90s, still had a mixture of conduit with rubber/braided wires running inside and some slightly more modern lead sheathed cables. The house hadn't been used since the war and still had the blackout blinds in place. It's a pity you didn't have any of these as examples.
Another great video, I’ve been looking for information on identifying tinned copper and aluminium twin and earth and there doesn’t seem to be a lot out there but you really help.
I still smile when I do work and find old earth sleeving. not just solid green but I come across solid green fabric sleeving a lot in our early 1970's complex
Highly satisfying and informative video! thank you John!
Nice informative video as always JW. It is a very different system that you use in the UK compared to here in the Netherlands. We don't use flex (only as ground cable) and have always (from the 60's and upwards) used solid core wire. It is only in the last decade that we use the multicore wire (6mm2) as buzzbar interconnect wire. Fun fact, in New Zealand they still use the "classic" red and black. Was on a job site 7 months ago and apparantly blue and brown is not mandatory yet. Keep up the good work, love the show! Cheers!
In former Yugoslavia was mandated 3 phases in every home to save on copper, so high power devices can be powered by 5x2.5mm up to 11kW (even that is oversized). Max current was 16A but over 3 phases.
Many homes had 20 or 25A limiter fuses, and the only cable from the power meter to the fuse box was 4mm.
In our system, every wire had insulation.
Facinating history lesson. Thanks!
@ John Ward,
When I first started my time as an apprentice, we used to work in houses here in New Zealand that had timber capping with varnished-cambric insulated conduit wires, this was the late 1980's.
Further on, you'd strike things like lead coated single cores as mains feeding a commercial building, the glands they used to use as an entry into a switch-board intake are something I've never seen since and they all had to be linked together to stop things like Eddy Currents from heating the intake area up and melting the lead coverings.
You had to be very careful bending them cables, even with the power turned off, because if you over-stressed them (which was so easy to do) they would split and let the chalk out and you ended up with a dead short on that cable.
I don't miss them cables.....
Thanks John for another excellent and very informative video. Best.
In the UK there are many properties built in the Sixties with single core wiring and no earth on the lighting circuits.
John,
I think many may be Interested in:
which of these sorts of cables 'in deterioration' will actually show up as reduced resistance on an insulation-resistance-test ? All of my older 7/0.29 and newer 2.5mm/1.5mm cable circuits, seem to be over 500meg-ohms with no issues...
I've stripped out stuff in the past that I guess was from the 1930s or so. Wooden trunking with cloth covered cables (looked like waxed cloth). The junctions were made by twisting the wires together and screwing on porcelain insulator caps. Looked like a perfect recipe for starting a fire!
That stuff wasn't that bad when new - but after decades it all dries out and crumbles to dust.
Wiring from that era only had a 25 year lifespan, and it was expected to be replaced after a couple of decades.
The rubber insulation crumbled, but the wire nuts were typically just fine (modulo the copper patinating :-)
The blackened/corroded cable might be due to water entry. The stranded conductor can wick water far into the cable.
Another very good informative video. I believe that long term aluminium wire is a problem due to creep at room temperature due to the stress exerted by the securing screw. This leads to the screw becoming loose and hence a bad contact which can overheat. The situation is made worse by aluminium oxidising rapidly in air ,so when the screw loosens air can get to the aluminium and oxidise it. Creep is also the reason why soldering the end of a muticore wire before screwing it into a plug is a very bad move. With solder the creep happens on much shorter timescales and a loose connection results in perhaps months or less. The reason the earth conductor has a smaller cross sectional area is that it does not have to be continuously rated. It only carries current for a fraction of a second up to minutes, typically, until a fuse blows or the circuit breaker trips.
Good points on the aluminum and protective earth conductor, thanks. But re "soldering the end of a muticore wire before screwing it into a plug is a very bad move": nope, the screw contacts should be tightened up enough that they bite into the copper (the tin's much softer), and the copper won't creep. Of course, I'm assuming that the wire's (correctly) tinned, rather than that there's a large blob of solder :-)
What about those older types that were installed on the 2 seperate strands sitting on a glass insulators?
Usually in Estonia 1,5mm2 is used for lighting and low current sockets (door bell) and 2,5mm2 for standard use sockets, 1,0mm2 wall mount cables are not much used here. Cords may be that dimensions, but not cables. Also earth is always insulated with yellow-green insulation and always matches the other cores, smaller earth cable is definite no-go up until 16mm2. Sometimes there's no earth in lighting circuit even in new installations to save construction cost. Usually the outer plastic is white or very light grey and fire proof is orange outer plastic, the profile of the modern cable is round, not flat. From 1950's until 1990's we also had bare aluminium cabling used, mostly without earth with a profile similar to the UK version, with all kind of random insulation colors, it wasn't even rare to see both cable cores white.
+DjResR
Weird. One would think that this would have been a sort of thing the Soviets would have been really efficient standardizing in.
Old Finnish color scheme btw was black (primary), green and yellow for phases, white or gray for neutral and red for PE (usually not used), but things were far from standard. In non-earthed or PEN systems for example, red was routinely used as the third conductor in places like stairway circuits or electrical outlets under light switches.
Hi John, Prior to the 1990s the average uk domestic household typically used around a 100 watts to light the average room via a standard bayonet lamp holder. At the time 1.5 mm2 T&E was the norm for a domestic lighting circuit installation. Around the same time as the evolution of the diachroic halogen lamp in particular the 50w GU10, it became common practice to reduce the CSA of lighting circuits to 1.0mm2. I have observed many lighting installations where a single large room can exceed .5kw. I also find 1.0mm cable to be quite delicate and can be snapped easily by some accessory terminals. Multiple stocking of both sizes of cable for appropriate installations is expensive and tedious. For these reason I will always use 1.5mm for lighting circuits. It will also allow for uprating of light fittings which can be legally carried out by a non qualified person, potentially overloading a circuit constructed with 1.0mm cable and protected by a 10A protective device. The introduction of LED replacement lamps has of course changed things slightly, but until tungsten lamps are no longer available for purchase, I will continue to follow my rule of thumb. Great videos by the way. You are always very informative, thank you.
Your videos are really good.
Any chance you can do a video on earth fault loop impedance testing ?
Thanks for the video and in depth information. I think solid core earth conductors is a really bad idea. They are more likely to work loose over time if not consolidated correctly. What are your thoughts?
Thank you JW :)
I often wondered why some was white and grey in early years. I live here in South and a house I lived in had grey cables. I preferred the old wiring codes eg red stood out more for being live. Yes that current 3 core 2 way cable is as dull as dishwasher prefer red yellow blue. Whenever I used that cable I used yellow as common red on red looped in to L1 and black on blue looped into L2. Now I use grey as common brown on brown and o blue on black as opposed to the previous way
I had a rewire recently where the guy had attempted to replace a single socket and attempted termination and snapped the conductor so many times it became excessively too short and became unable to turn the circuit back on. Turns out the whole house was done in aluminium, had a relatively recent fuseboard (Cheapy Wickes thing) with some old 10mm(ish) Aluminium tails coming out of a suppliers switch (I assume because the meter installer didn't want to connect on to them, but someone did anyway) and for the Earth connection to the whole installation the 'electrician' (I assume to be a previous owner) decided to strip some 1.5mm flex and use the green&yellow core.
Great video John, thank you.
1. I was told years ago that the earth was smaller cross section as it wasn't expected to carry a sustained current as the other conductors were and so they could save on the copper and make the cable more flexible. Is that correct?
2. I have always been amazed by the 3 core and earth colours going from as you say, sensible, to shades that all look the same in poor light with some plaster and dust around.
3. I was told by an electrician some years ago that 'no professional' used 1,0mm2 and that everyone used 1.5 for lights. I really never understood that, especially after threading cables for my uncle years ago. 1mm2 was much easier. I am glad that he was incorrect.
Always welcome your thoughts and welcome seeing your videos. Thanks.
+Colin Herbert Yes, the earth will only carry current under fault conditions and then only for a very short time, unlike the main conductors which are designed to carry the full current all the time.
About 10 years ago I found a full unused reel of lead sheathed 7/0.29 in a shed. I stripped the end to see what it was like, and it was literally like brand new.
Very informative video and great guide to everyone in the "Sparks" line of work. Have met up with the rubber variety and it does crumble away. The new EU colours are depressing to say the least----so much for the EU colour palette.
Tom OConnor depressing other not, at least colour blind people can tell the difference easily enough
jw mentions the brown black and grey being difficult to distinguish in low light but ive found the blue and brown to be equally difficult in low light, they all look the same
@@TheTomco11 That is a myth. Colour blindness was the reason for using a green/yellow earth as green and red look very similar if you are colour blind. This has nothing to do with the other colours.
Great video, thanks very much.
Copperclad. I expect it's the same stuff that comes into my house carrying telephone signals? We have fibre broadband in my street but if you have rubbish wires coming into your house you end up with some of the slowest speeds in the country..
Fascinating stuff is cables. Many years back when bored in a museum one of their displays grabbed my attention. (I think it was the start of my love of machines and industry..). The display was originally part of a larger display in The Great Northern Exhibition at Newcastle upon Tyne. This particular display showed hundreds of different electrical cables. They had been expertly peeled back in layers to show their intricate construction. To show the world what the North East could do..
I have no idea what happened to that display case but hope it survives.
Oh! You missed out on lead covered household cable ;)
+Zeal Ashwar Yes they used copper clad steel for the overhead dropwires for phones for years (due to the tensile strength). Nasty stuff to strip because it's quite hard steel (bit like piano wire!). Quite often it's sole job in life is to stab you. The insulation often becomes porous and if the inner steel is exposed due to the copper plating not being complete, you can end up with a rust filled tube of copper foil as your conductor! If you ever get an external line fault on the circuit, make sure they replace it, as the stuff's not even twisted pair (it's usually a figure 8), it will indeed b*gger up broadband.
+TheChipmunk2008
I dream of better broadband. It's 30 feet away beneath the footpath outside my house but they won't complete the faster connection. You couldn't make it up!
Cheers for that though. I remember seeing the steel/copper mix many years ago when collecting scrap metal for my dad (I was a child). I gave him some and he swore at it haha!
I wish I'd kept a sample of some of the aluminium solid core twin and earth from a house I rewired a couple years back. An old lady lived there since it was newly built and hadn't had any of the electrics touched at all, until her son tried to change a socket and broke the cable so many times it became impossible. All the other terminations throughout the installation were properly done with the anti oxidisation gunk. I didn't appreciate how rare of a sighting it was at the time 😂
I think the rubber cable is still manufactured with current conductor colours and no earth wire for festoon lighting that uses screw-on lamp holders such as Beeantee. It isn't widely available though.
Very good John.
Hello John, I have a question, Im getting an industrial shredder which is being converted from phase 3 to phase 1, not sure if a house here in the UK can handle the shredder, I was told its 5.5KW, Im just worried the motor will blow and its bloody expensive, I told them to make sure it is made for the UK, should I be worried or is it ok, dont know much about electricity.
I'm seeing a lot of 0.75mm cables on various website are these any good? Looking to hook up some LED PIR Motion Detection Lights outside
Thanks for the education
My house (in the States) is quite old & uses BX or armored cable. That is, the cores are enclosed in a flexible steel jacket (which can also serve as a ground/earth). Also, some of my cable has cloth-insulated cores. Is/was there any equivalent in the UK?
Thanks for the interesting video. One question, does the current carrying capacity differ for the same size stranded and solid cables?
Still a house near me that was (and probably still is) running a raw aluminium solid-core ring circuit. House is fairly modern inside too, and doesn't look that old from the outside, so the stuff is definitely still out there being used. I cringed connecting it back up.
Another thought on old cables: Ever observed that green/blue goo that oozes out of some of those? I think I read it to be due to a breakdown of the chemical constituents of the plastics/rubber used.
And how do you strip those outers so cleanly? Stanley? (careful not to score into the inner insulation now...). ;) Or am I missing some nifty little tool from the tool bag, like the recently discovered beauty of an SWA stripper...
And, yes, harmonised colours suck. I miss RYB.
+9ff70f96 +9ff70f96 The examples were all stripped with a knife, no special tools there.
Green slime video: czcams.com/video/dQfLXHweDv0/video.html
In Australia we always use 1.5mm for lighting, all cables are stranded, only old stuff is solid core and the earth is insulated for its entire length. Also ring circuits aren’t legal here however I did once live in a house with a ring power circuit. It was wired by a retired British sparky.
I split it into two 16a circuits 👌
Thanks for another great video JW. Might one reason that 1.5mm is used more as time goes on, be the increasing depth of insulation? With lighting cables sometimes being underneath 270mm of insulation in the loft?
Not really - 1.0mm² clipped to a surface is rated to 16 amps, and even the worst possible conditions (totally surrounded by thick insulation) would only reduce that by 50%, so it's still well above the 6A circuit breaker normally used for lighting circuits.
Voltage drop might be an issue, but the circuit would have to be exceptionally long and with a rather high load - neither of which is likely in a typical house.
That's interesting, it does seem OTT to use 1.5mm then, thanks
I'd never heard that the Great North South Divide was also in cable colours. In the 70s we'd use grey for power and white for lighting - but I've come across this so rarely that I wonder if it was a purely local convention.
I have to be honest - I'm pretty gentle when people ask me "Do I need a rewire?". If I find VIR cable then my answer is "Oh yes - definatly" That stuff went out with hitler. If I find aluminium, however, I'll inspect and test the cables. If they are good, I offer a lower cost service of changing the consumer unit and going around re-terminating everything into new accessories neatly using ferrules. Of course, any extensions to the circuit will also be made with ferrules on the old conductors. Generally, if the insulation is PVC, I'm happy. Naturally if they order a full rewire then thats what they get but I make it clear that it is not absolutely neccessary in most cases. There are also occasions where its a half & half job. When I find no earthing on the lighting circuit, I do as stated with the other older circuits and rewire the lighting so class I fittings can be installed.
Hi John, what is an acceptable way of extending twin and earth cable?
Bill Carr
Hey john its against an electricians nature to ever educate people on electrical systems... But the way I see it creates more work for us lol
choc boxes with an access panel , is the cheapest way but you can use any type of joint as long as you can access it . And it will always be regarded as a new point on the circuit.
Hi, thanks for the great vid's! Can I ask you if It's ok to use a thicker twin & earth cable for my lights in my house, as I have some cable left over. Thank you
Hi Mr John how are you doing. Great videos well done to you . I think you are the best electrician. I would like to ask you a question? I have 1.5 mm on the shed waterproof cable but I would like to put it on the wall outside can I use it ? That cable has been used already for sockets inside shed for many years . Thank you
I am fitting a 8.5kw shower what wire would you use a 6mm or a 10 mm please let me know thanks
should earth cable be on both sides or on one side?
Question, can you still obtain 20amp fuse wire from a reputable supplier for an older installation or do you have to downrate the circuit to 15amp as you now only tend to find 5/15/30amp packs available ?
Yes, available from most electrical suppliers, one example: www.cef.co.uk/catalogue/products/23827-20a-23swg-fuse-wire-100g
20A is rarely used, as the minimum cable size with rewireable fuses is 4mm², unlike cartridge fuses and circuit breakers which can have 2.5mm² for a 20A circuit.
my wiring is black and red but outside is lead but you did not cover this. Love my round pin plugs and no fuses to wory about. not changing nothing as it works not fine. do not scratch the red wres though because they spark and through you backwards and hurt
(Unless you are depessed when you feel life is worth living again)
+111kenni Obtaining examples of lead covered cable is difficult, because it is over 70 years since it was used.
Hello again John Can you get your hands on a cutting of lead covered cable to show everyone. I wasn't around when it first was used but it must have been real heavy stuff to carry. Iseem to remember that It was good for making little mouse for going down wall cavities.
czcams.com/video/O87Pj-rjqrU/video.html
You mention "over sleeving" at 5:30. I have never seen anyone do that here in Denmark, except for with green/yellow heat shrink tubings for protective bonds. I understand that you want to add a green/yellow sleeve to the bare copper to identify it clearly. But if I understand you correctly, you suggest putting fx a blue over sleeve on a grey wire. Is that because it is mandated? If so, I would like to know more about this. If you have a link, please share. And exactly what are these over sleeves? Are they heat shrink tubing? Are they pieces you buy to put over, or do you take insulation from another cable and put over? Sincerely
It's most commonly used for a cable to a switch, which has line and switched line. Cable with two brown cores & earth is available, but it's far more usual to just use cable with blue and brown cores, and put brown sleeving over the ends of the blue core to identify it as the switched line.
Regulations require that wires are identified by the correct colour, sleeving is the most common option, although others such as coloured tape are also permitted.
It's just a PVC tube of about 3mm diameter, supplied in large lengths and cut to whatever size is required, such as www.toolstation.com/shop/p29947
Brown is the most common, previously it was red for use with black/red cables.
Blue is used to identify the neutral where a 3 core and earth cable is used, this is usually supplied with black, grey and brown cores, and can be used for various purposes including line, switched line and neutral for things like extractor fans with built in timer.
Black and grey are colours used to identify separate phases in 3 phase wiring, sleeving can be used there if desired although most 3 phase installations use cables/wires with the correct colour already, so sleeves of those colours are rarely used for anything.
Isn't 4mm² used in 30A radial circuits?
The change from 1.0 to 1.5mm² ECC on 2.5mm² cable came in when BS6004 was amended in 1981 after it was realised that if you did the sums for a 30A rewireable fuse the EEC size came out at 1.2mm² minimum. (Paraphrased from my Peter Perigrinus Guide to the 15th Edition of the IEE Wiring Regs.)
Edit: Copperclad was BICC's trade name - a neighbour of my parents worked for BICC when it came out in the early 70s. The main problem was you needed the size up from copper for any given circuit - 2.5mm² became 4mm² IIRC.
+Graham Langley 4mm can be used on 32A radials in some circumstances (MCB or cartridge fuse). It does not comply on a 30A rewireable fuse.
+Graham Langley That should be ECC of course.
John, what was the reason for changing the 'core' colours from Red/Black to Brown/Blue? Im interested to know.
Making the colours the same across Europe, and more specifically that neutrals are always blue. The process actually started in the 1970s with appliance flex, but it took several decades before it was applied to fixed wiring.
Seems very similar to North American cabiling with the bare earth, flat, and with solid conductors, except ours has to be bigger due to the lower voltage.
14 AWG = 2.5 mm/2, used mostly for lighting limited to 15 amps
12 AWG= 3.3 mm/2 , used mostly for sockets and the like 20 amps max
10 AWG= 5.2 mm/2 , mostly used for dryers and ranges/cook tops, storage water heaters 30 amps max
8 AWG = 8.3mm/2, used for bigger cook tops/ranges, welders, etc 40 amps max
and the largest common size I've seen in an installation is
6 AWG = 13.3 mm/2, max current 55 amps, used for welder hookups or central heating. this stuff is seriously hard to bend, route through walls
The last three are typically split phase cables with 4 conductors, 2 hot/lives neutral and earth/ground. Amy thing bigger than 10 is stranded.
pilotsmoe for outlets at least, in the UK we use a ring circuit rather than radial. Each ring has a 32A fuse/breaker and the wire is only 2.5mm^2
Hi John, what's the size of electricity supply cable into into domestic buildings (homes). 50mm2? Thank you.
Depends on the property but 16mm and 25mm is common on new installations. Older ones may be smaller.
is it the case that if its a commerical building rather than a private dwelling it has to be the lszh stuff not pvc?
Very similar to Australia's wire except for the colure's we have red & black and earth green with yellow stripe, Same sizes 1.5mm 10amp twin and earth for lights & 2.5mm 20amp twin and earth on GPO's also for lights 2 way switching red and white with no earth just single twin, all our cables outer PVC are white except for air-conditioning cables being blue now for better identification plus they include a signal wire as well..
I was at a clients house recently and came across red, white and blue cable without an earth and the outer sheaths had become brittle. I was wondering what era it was from as the white threw me. Now I know. 👍
John you are a legend
Hi John, Came across a socket radial circuit with 4mm (Or imperial version) stranded red/black with solid CPC T&E today, what sort of date range would this be used please? Love watching your videos, please keep them coming!
Probably 1970s, although different manufacturers do make variations of 'standard' cables so it's not straightforward to date things just by their construction. Even today, it's possible to buy things like 2.5mm² T&E with stranded conductors rather than the more common solid ones.
Is minor marks, nicks or marring of the grey Sheathing permissible? I have pulled some old T+E out (had been stripped back too far, cut too short to be wired into a new socket), I have then worked some new T+E through the old Steel capping (against a breeze block wall) and as a result the wire has some minor nicks/marks on the grey Sheath. Neither the Line or Neutral insulators are visible and neither is the CPC. As the Grey sheath is just environmental protection, the most damage would be a thinning of this protection at a certain point. Is this an issue or am I over thinking things? thanks, Taylor
OK provided it is just minor damage. Cuts or sliced sections would not be acceptable.
first class stuff, just one thing i'm not sure that square mm and mm squared are quite the same thing ?
John, can you use it at a 3 pin plug?
good break down and very well explained. Thanks for sharing your skills.
Can you answer this question about flexible cord.
A flexible cord can be used to support a maximum of how many kg?
Haha college question? Look in bs7671 ;)
+Michael Thomas Between 2 and 5, depending on size.
thanks guys... they havent provided me with BS7671 yet, but found out that it's 5kg from 1.0 mm2 to 1.5mm2
I would like to see a video similar to this for stranded flex cable, preferably before I go importing cable from the UK for a small DC power brick repair project.
( the white oval 0.75 or 0.5 MM looks quite nice to replace the aluminum? on my Apple Power brick cord ).
As far as I'm aware, no half-decent manufacturer would use aluminium conductors in flexible cables. Are you sure it's not tinned copper?
this type of thin grounding it's to tripp the breaker unlike industrial ones which may carry current all the day.
Thanks to all your videos John. I recently came across a property which used the earth wire ( twin and earth) as a live conductor for their lighting circuit. I was shocked! It did have almost full sleeving. Is this allowed??
Not allowed now, and never was.
@@jwflame Thank you.
My house has no earth on the lighting circuit. I have a chrome faceplate light switch in one room. Is there anyway to make this safe or do I need to throw it out? Same with downstairs I have old 1960s brass faceplates (the switches themselves are plastic). Is this an issue?
Only options are to rewire the circuit to include an earth connection, or replace the metal switches with plastic ones.
For nice neat stripping of T&E, I use an Ideal 45-235. My neighbour was a rep for their UK agent some years ago and gave me a pair.
They're an American design, for Romex cables but are perfectly suited to our T&E.
I just hate seeing an installation where someone has used the earth as a rip cord then just peeled back and snipped the sheath leaving up to an inch of split sheath showing.
+Simon Parkinson Do they leave toothmarks on the plastic where they grip the cable? C.K Automatic Wire Strippers 495001 (or similar copies of the same patent) also work very well on flat cables, but they do leave marks. In the videos the cables were perfect so John is clearly using something else.
+stefantrethan Yes a little but they tend to fade.
You can make a shallow incision with a Stanley knife around the sheath and with some care slide the blade along the earth stopping just short of the incision. the sheath will then separate cleanly where it has been scored.
Thanks John for your cable review. Fitting the green and yellow sleeving of the earth wire inside a plug can be a fiddle especially if the wire is stranded. Apart from the regulation I supose the only advantage of fitting the sleeve is to help avoid the possibility of a short out from the live wire near to the terminals ? Measuring the cross section of recycled cabling can be a pain. It seems a pity they don't adopt some colouring or marking on the outside sleeve to indicate which size and type of cabling it is ! In underfloor installations subject to possible rodent attack is there any particular advantage in using armoured cabling with outer wire sheathing ? Clive on his channel indicated that our habit of fitting ring circuits in domestic installations was disapproved of on the continent ? Are these avoided now in our modern installations ? Thanks again.
+meandmymouth Use of the ring final is still commonplace in new installations and it still in BS7671. Radials are used where appropriate.
+meandmymouth Most modern cables are marked with the number of cores and size, but older ones may not be. It's also a problem when you have a short piece as the markings are typically only repeated every metre or so.
in the US a couple NEC revisions ago they started specifying wire size with a color. white=14AWG, yellow=12AWG, orange=10AWG and black=8?AWG.
this is mainly to help inspectors verify correct sizes for circuits, however it makes picking wire off-the-shelf a lot easier to ( Or for that matter out of my piled in the basement ).
I remember coming across some 7/.029 twin in the 1950's with pvc outer sheath with rubber ins: inner cores. Was this ever generally used?
It was for a few years in the 1950s, although it may have been polythene rather than PVC.
There were various combinations such as rubber / polythene and polythene / PVC, with names like Capothene and Ashothene.
Thanks, at least i wasn't hallucinating as everyone else i mentioned this to said there was no such thing.
Great video thankyou
Very impressive most of your video but you haven't done any video about inspection and testing or visual inspection on the cables or conductors termination, checks, confirmation and human senses of a consumer unit.
It would be great if you do that. Thanks any way.
Would this be classed as 70 degrees thermoplastic insulated single core cable with copper conductors in BS7671
Yes to 70C thermoplastic insulated, however multiple cores not a single core.
Sounds like a weather man teaching about cables but, good info
Hello John I was looking at an industrial installation recently and one of the electricians was complaining that YY cable should not be used on cable tray. I have had a look at the standard and from my understanding flexible cables can be installed on tray although may not be preferred due to mechanical considerations. The 18 edition doesn’t go into detail regarding what exactly are the mechanical considerations but these cables are installed at high level. I know that this type of cable is commonly installed in France and Germany etc so it meet the relevant EU standard to be installed in the U.K is within the EU and our standards are harmonised. I not an electrician but just wondered if you could answer the question I have asked 4 people and got 6 answers so far? Many thanks Regards Chris.
Flexible cables can be used, but the problem with YY and similar cables is BS7671 (wiring regulations) specifies various other standards that cables used for wiring installations must be made to, and YY cables do not comply with any of those standards.
It is possible to use cables and other items which comply with other standards, but only where they are equivalent or better than the UK standard, and that is very difficult to prove in reality.
Most manufacturers of YY, SY and CY cables state that they are not compliant for use in fixed wiring installations, therefore by using them you would be ignoring the manufacturer's advice and also claiming that these cables are actually suitable despite them not being listed as a suitable type in BS7671.
Therefore YY and similar are not suitable for fixed wiring installations, whether on tray or anything else.
John Ward That’s a good answer. Thanks. Does that hold true for control wiring and low voltage installations. It just seems strange because the 18th edition does have tables for flexible cables and actual gives examples of installation on trays etc. The equipment is a distributed machine in a building so the wiring is not being used for stuff like plug sockets and generally lighting, its an interlocking system for control of automated gates. I’m just surprised that this has never come up before when I see it so frequently installed In this type of application etc? Thanks John.
BS7671 doesn't cover control wiring if it's part of a machine or similar, so if used there BS7671 doesn't apply and neither does the restriction on cable types. Other standards would be used for that.
Flexible cables can be used on tray for other circuits such as lighting, power, and often are, provided they meet one of the standards listed in BS7671.
John Ward Thanks John that kind of makes sense. I guess I need to spend more time trying to understand the 18th edition. I think some formal training is in order as I don’t do electrical work myself but I do employee electrical contractors to do work for me.
You didn't mention lead coated or the rubber T&E that had some kind of fabric on the outside, was it VIR??. I even dug out a lead cable junction box on a rewire in the early 80's, the earth wires where twisted up together on the back side of the box.
I used to use 1.0mm twin red and earth, later twin brown and earth on new houses and extensions, I found it helped when the house owner had a shopping trip on Saturday afternoon at B&Q and came back with some crap Chinese pendant, they ripped off the original ceiling rose and forgot which wires went where so put all the reds together and all the blacks together (or browns and blues), and switched on to a bang. At least with red / red (or brown / brown this way when they linked all the colours together there was no bang, just a light that never went out. And then comes the phone call about how the lights where working fine this morning but suddenly won't turn off.
Anyway good video JW as usual.
My house is mid 1950’s. The main ring final circuit is twin (red and black) PVC insulated with what appears to be a steel earth run in parallel, but not enclosed. Is that common? The lighting radials have no earth. The PVC insulation is still, apparently in good condition. Both soft and flexible.
It was fairly common in the 1950s. The earth is most likely tinned copper.
Insulation may be polyethylene rather than PVC, various different plastics were used in the 1950s/1960s before PVC became the standard choice.
I tried to install a broken twin 13A MK socket for a family member, but when I took off the cover there were two inputs, one for each socket which was done by what you would call a friend of a friend and therefore probably a crap electrician which was fine for right side input. How would you go about sorting that without hundreds of £ of plastering and rewiring? There is not enough length to reach the MK terminals because the wires are so tight.
+ChompChompNomNom The wires can be extended using suitable connectors, provided there is space in the box behind the socket.
Thanks!!
I had a house in the 80's with wire twisted and covered in some cloth
+Tangobaldy That is textile braided cable, i'm not sure why they started using that, Usually its used for Retro fit out of lamps to make them look period to to the time and on some small appliances.
Wires in my house are round rubber wire. Got to be getting on for 70 years old.
Installation should be tested every few years anyway.
Hi John, I have an electric radiator that was wired into the wall socket for economy 7 usage but I need to put a standard 3 pin plug on it and use a thermostat. My only thing is there is four wires not three...I was told the black and brown wires can go together but some advice would be very much appreciated.
Depends on the heater and the function of the black wire - it's probably a control or pilot wire so that multiple heaters can be controlled from a single location. You will need to check the instructions for that particular heater, guessing is not an option.
@@jwflame sadly not an option. If I could send a photo I would.
Thank you John! here in the US, this wire is known as ROMEX. now, why is the Earth lead still smaller then the other conductors? Here in The US, all conductors have to be equal in size and value. the Earth has to be able to carry the full load of a short, if it is smaller then the other wires, it could fail.
Earth is smaller mainly because it makes the cable cheaper. It can be a smaller size compared to the other conductor as it only carries current during a fault, and for a very short time - from when the fault occurs to when the circuit breaker disconnects - typically less than 0.4 seconds.
What gets me is that the earth wires are always considerably smaller than the line and neutral. You'd expect the earth to be able to handle more current than the line can supply.
+TestECull I believe the theory is the rcd/gfi will pop before the wire heats up.
The trade off the wires size is based on heat / resistance. So its probably ok on a rcd protected circuit.
Smaller wire = higher resistane = more heat. So you could run 1000s of amps though a small gauge wire for a short time...
Voltage drop also happens but wanted to keep it short.
KingOfKYA
Might be that I'm from a country where RCD-protected main circuits are abnormal, then. We don't have ring mains or RCDs in our fuse boxes over here so having a hefty ground/earth is pretty much mandatory. It's perfectly plausible that a device could fail internally, in just the right way, where the load dumps its return to the earth instead of the neutral. Such a failure would probably be completely unnoticed as the device would otherwise function normally, wouldn't pop the breaker.
We have RCDs, but usually built into the sockets themselves and fitted only where the device plugged in could find itself taking a swim. Bathrooms, outdoor sockets, generally speaking there's no RCD in our walls. Often, bathroom appliances in particular are double-RCD, because there's so many bathrooms lacking RCD sockets in America that they're mandated to be in the plug itself as well. My house is 40+ years old and the sockets in my bathrooms all predate the standard change, so it's necessary for me.
here in the uk twin & earth with a smaller earth than live core has been around long before rcds became common
Cheers my shower cable is red,black and is stranded cable will this be 10mm or 16mm cable please
Could be either as both sizes are stranded. 16mm² would be an unusual choice for an electric shower, 10mm² is more likely.
Do 1.8kW showers really need a larger gauge cable than ovens? I thought ovens often used 3kW+
+David Ellis he said 10.8, :)
Oops! That makes more sense...
David Ellis a shower uses the full power of 1.8kw constantly whilst it's on where as an oven uses around 3kw but over a longer period off time. The oven can be on all day but a shower can't if u want to save electric . I hope this helps.
@@danielmeegan9677 Not really helpful. an instantaneous 1.8 kW shower would be useless, raising the temperature only a couple of degrees. And ovens often stay on for hours at a time (Christmas roast) whereas it would be rare to shower for more than 15 mins at a time.
Why was the colour changed in 2006? It makes more sense for Live and Neutral to be labelled by Red & Black (in my opinion). Or is it because DC cables are usually red & black?
+Alex Scott Yeah, Red and Black is used for low-voltage DC projects. Also, Red looks like black to certain color-blind people. Here's how they look like, just scroll down to the blindness sim:
www.colorhexa.com/ff0000
www.colorhexa.com/9f6934
www.colorhexa.com/0063ea
pilotsmoe Yeah. And you have white for neutral? I finally understand all those videos, when they wire a mains project.
European Harmonised colours Alex. The simple answer, was so that horrible European cables can be sold in the U.K. and that my friend is the REAL reason. When red and black was only used in U.K. it was made by quality companies, and was a joy to install, strip and terminate. Architects and designers usually specified something like AEI/Delta or other recognised manufacturer, and all was good in the proud industry of electrical engineering. Ruined forever now.
Got2Bgaga Interesting, thanks for your input