It's NOT SWA Cable Feeding Your House Cutout Fuse
HTML-код
- Опубликовано: 28 апр 2024
- What is the cable supplying your 100, 80 or 60 amp cutout fuse in a domestic property?
Concentric and split concentric cable explained - aluminium line conductor and a copper combined neutral and earth conductor in concentric cable. The split concentric cable has and aluminium line conductor and copper neutral and copper earth insulated from each other. We see how a concentric cable can be mistaken for a SWA (steel wire armour) cable coming into the bottom of a domestic cutout.
TN-C-S TN-S
T = Terre N = Neutral C = Combined S = Separate
🕕 Time Stamps - Cut to the action 🕕
00:00 - Concentric cable is feeding your cutout
00:30 - Intake equipment
00:59 - Fuse sizes
01:31 - Electric meter
01:45 - Meter seals
03:00 - Concentric cable
03:07 - Aluminium line conductor
03:15 - Copper neutral earth
03:49 - Pulling the cutout fuse
04:37 - Cutout connections
05:03 - TN-C-S
05:42 - Connection on the meter
06:26 - Split concentric cable TN-S
Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.
You can follow me day by day on Facebook, Instagram, Twitter and TikTok lookout for "GSH Electrical”.
▶️ FACEBOOK / gshelectrical
▶️ INSTAGRAM / brihzmraygdtmjmdb9lunq...
▶️ TWITTER / gsh_electrical
▶️ TikTok vm.tiktok.com/ZMRBLFdhe/
#GSHElectrical #Electricaltrainingvideos
Left the financial industry end of 2020, been going to college to study electrical, sent out over 200 emails to companies trying to get a start. Coming up on two years later from leaving the financial industry I have started my adult trainee apprenticeship with a one man band taking me on. These videos and this channel have been vital in learning for me. Thank you so so much to the main guy always in the videos and the whole GSH team. Thank you so much.
The team at GSH are inspired and thankful for your comment and watching our content 👍🏻. All the best and thanks again Gaz
I take it you were not well paid in the financial industry then?
@@deang5622 with the pandemic came a lot of time to think. Sitting at a desk all day wasn’t for me. I’ve lost 3.5 stone since Jan 2021. Psychically and mentally a lot better off.
@@mikestepz3945 Quite a lot of electricians cause permanent damage to their knees...
@@deang5622 yeah I heard that, seems like everything in life is trade offs.
Well I never, 61yrs old and been in the trade since 1979 and never seen or heard of a split concentric cable. You learn something every day 😎.
The apprentices have it easy nowadays, we never had trainers like you, ours were ones that probably ones that were conscripted in the 50s and were still using valve radio 🤣🤣🤣
Thanks for taking the time to watch and comment 👍
Massive thanks for all your efforts to create content for the electrical industry 💕
That video will help so many new learners. Wish I'd seen it 2 years ago when I first started .
Thanks for commenting and the support 👍🏻
Brilliantly clear explanation, as ever. Thank you, Gaz!
Thank you 👍🏻
The cable coming into the house I am in now is a concentric cable but without pvc insulated core - the core is wrapped in oil soaked paper and around that is a lead sheath. The lead is the neutral/earth and the central core is line. This arrangement allows the guys working on it to be able to cut into the cable whilst live with plastic tools in order to create a joint. I watched them do just that and it was very interesting.
Fascinating video. I never knew the name of this type of cable but its application is very useful. I've repaired Apple MagSafe chargers before and they too use a concentric cable. Thank you.
Excellent presentation, both in the field and in the classroom. Never too old to learn something.
Thanks for the nice comment 👍🏻
It's fascinating to watch how electrical systems work in different countries. When I saw the concentric cable, I immediately thought of coaxial antenna cable because it's made in a similar way
Thanks for commenting and watching 👍🏻
In the U.S. we don't use concentric cable for normal building entrance wiring, however, it is often used for 7200 Volt single phase underground feeder cables.
Yep. It's low impedance, low frequency, high power coax.
Nice one gaz brilliant as always 👍👍
Thanks 🦾💕🦾
Great stuff Gary
Thanks 👍🏻
Well presented tutorial. 👍
Once again very well explained.
Thanks 👍🏻
Recently started my apprenticeship last month, all seems daunting at first so hoping I’ll get into the swing of things
All the best with your studies 👍🏻
Great presentation! Thanks
Thanks for watching and taking the time to comment 👍🏻
Fantastic video
It’s worth noting there is 1ph split concentric and 3ph split concentric out on dno networks on the 1ph conductor size you normally will come across 16mm split 25mm split and 35mm split concentric 3ph most of the time I have come across numerous times in 35mm. Split concentric service cable main purpose is to match existing earthing characteristics of the lv network in some areas direct earth or separate neutral earth is the only earthing system available. This type of cable comes into play a lot of the time on service alterations were a 1ph pilc or three phase pilc service is being moved to a different position so to match existing direct earth or separate neutral earth characteristics of the house split concentric is installed and a transitional straight service joint would be jointed onto existing pilc service or split concentric service.
Massive thanks for taking the time to give your input 👍🏻
@@GSHElectrical your welcome your channel is excellent great content and very informative 👍
Not sure of your location but in the NPG, North East England. a single phase service will normally be split neutral and earth but a 3 phase will be combined neutral and earth with a separate earth conductor out to a stake.
If its a new service all together either will be combined neutral and earth and the customer provides their own earth.
The DNO only provides an earth if there was already one there. There is actually a big issue with earths and DNOs.
up till recently they did not provide an earth as such, it was the lead sheath of the cable which was earthed as protection for the sheath. But many Electricians adopted this earth as their main earth if it was there and it became standard practice.
When privatised DNOs realised the legality of these earths and stopped guaranteeing them to be of good value.
The IEE didn't like that idea, over time new regs introduced state that if an earth clip was fitted to a lead cable by DNO they had to adopt it and if a property had what had been seen as an earth from DNO any alterations had to include an earth.
For ease we just put back what was there or its equivalent until it came to 3 phase services as above.
it was a fun 5 years or so...lol scratching your head trying to figure out what to do on each job.
Qick note.
we called them SNE and CNE, separate neutral and earth and combined.....
Good man. Thank you. Simple once we know.
Thanks for commenting and watching 👍🏻
Good Video , however its from the Utopia Earth World (parallel world) where everything is good and proper as it should be..... but most of us watching know we dont live in that world unfortunately..... 9 times out of 10 times the cut out /origin of the supply is shonky wiring with old meter tails usually 16mm where the sheath of the double insulated is stripped back too far and the meter is stuck in a position taking up too much space so the new dist board doesnt fit....so a lot of us dont have the time and niether does the customer to wait around for the electricity bods to faff around fixing their end and pulling the fuse.....
So we steam in, cut the seals , put new 25mm D/I tails from head to meter to new distboard having re arranged the space to accomodate..
Making a better, neater and safer job all around...
Most of the DNO guys arent proper skilled sparks but have a day or so training to fit meters and fuses..
Im not saying everybody is this way but a lot are and care more about a proper safe install then box ticking, ipad tapping form filling, time consuming, logo shirt and hi viz wearing poor grade installing workers.....
P.S
And for all the sheeple who will have a negative saying against me about ooooh your breaking the law and rules ..... yeah well so what... my concern is for a good safe job in reality... not a good paperwork exercise ...
And in anycase.... the Cut Out in the video is poor as its on a floaty board not even fixed properly in the white box.... tut tut !
The problem is the term electrician or "spark" is too general a term. It like saying you're a doctor. A cardiac specialist doesn't do eye surgery but both have a basic understanding of biology. The reality is "DNO guys" don't care about the trip time on an rcd or the if there is an A type or S type rcd being used in the fuse board because it's completely irrelevant to there day job of maintaining and building a distribution network, just like a "spark" would be clueless on landing a transformer 11kv to 400v. DNO guys go through a 3 year apprenticeship for the basics before further training to move up. The days training you refer to is most likely the supplier who are responsible after the cut out and own the tails from the cut out to the meter you appear to be changing. And also own the meter and have done for the last 20 odd years since privatisation. Also the cut out is fitted correctly on a slopped board if the cable entry is at the front of the box.
Well said. Since starting as an apprentice in 2003/2004 (even had Gaz as a lecturer back then) through to now I've never known any one wait for them to come out, it's just not cost effective or efficient on time.
@@roblewis730 that may be so. But it's one of those things you don't own or have a right to work on supplier or DNO equipment. So if you're the last person to work on it and there's an issue later on e.g. a fire . Your insurance isn't going to be interested one bit.
All smart meters record when the cover is removed. I suspect suppliers and DNO have there guys on trackers. So isn't going to take much to figure out not to do with them.
@Mark Bradley . Ive been a sparks for around 20 yrs & worked with quite a few various electrical companies & most of them Do remove the main cut out for there own safety. Trying to contact a human being at any supplier normally takes hours & then you have to wait for ages fir them to turn up to merely pull a fuse. If youre competent enough is far quicker & safer to do it yourself. I know its wrong but makes life soo much easier.
Personally I've been onto british gas in the past & been on the phone being passed from pillar to post for over 4 hours either trying to get a " test & connect" or just to pull a main cut out. Ive also Twice come across a reversed polarity in the cut out due to incompetence from the DNO & also had very loose tails fall out of the meter.
Ive also had a customer that had a fire due to loose tails After they had done a fresh install.
I prefer to use my own initiative and re tighten all tails from meter & main fuse & quite often find them to be a bit loose.
"A fuse that you'd never pull out under load conditions" 🙂
Many will be amazed that the earth and neutral are connected. So a metal cased appliance that is earthed, will be connected to the circuit as you are touching it, and the circuit drawing current.
Thanks to Gary GSH Electrical we are still alive here and most important safe.
Good vid 👍
Thanks for commenting 👍🏻
Many thanks nice and clear
Thanks
By me the split concentric cable also always has 2 0.5mm copper wires in the outer as well, used for communications between an indoor display unit that id part of the prepayment system, to communicate data back to the head unit on top of the pole, that is the actual metering and disconnect. The display is powered and communicates over these 2 wires, so that you can top up your prepayment meter easily, but tampering is hard, as the cable will be dead when your credit is exhausted.
Not in the UK which is the situation here.
My premises has the equivalent of SWA. installed in 1927. Several years ago, SPEN created a new earth for me, by paring back the tar insulation, fixed a clamp (think it was actually a big Jubilee clip!) to the steel wire and ran an earth to the consumer unit.
paper insulated lead sheathed cable from memory, though my memory ain't what it used to be.
@@chrisgreenwood271 I’ve absolutely no idea. It’s a big thick cable that appears from underground and obviously wire wrapped. They said, I’ve now got the best earth ever, because it goes right back to the supply. I presume that SPEN know what they’re talking about.
Question about the 'split concentric cable' at the end of the video;
I heard that normally you can't use two smaller gauge wires in place of one thicker wire, because if there is a greater resistance in one (because of manufacturing differences, cable length, temperature, or cable damage etc) it'll end up drawing too much current and heat up.
How can these multiple insulated cables be used as a single neutral bearing that in mind?
They are used as one, they are only insulated so they can't touch the earth wires which are un-insulated.
The wires are all the same size and any difference in length is negligible.
This situation you mention would only be an issue if there was a large difference, meters of difference or in very low voltages, sub 1v, electronics etc.
Good vid
Thanks 👍🏻
we use 63amp over 60 mostly now.
Interesting - and answers some questions too. For the benefit of those of use just absorbing knowledge via osmosis rather than going for qualification, could you clarify why you're say "line and neutral" rather than "live and neutral". I figure there's a very important distinction that if I'd watched a particular previous video, I'd be aware of. A link to that video would also be good :D
Thanks guys.
If the double pole isolater has a tag shall I leave it and not cut it to give the board power ?
If only the audiophiles knew that their power is supplied through an aluminium conductor! Lols
What size would the incoming cable normally be in practice, given the copper meter tails are 25mm I would expect the cable to be around 50 percent larger in CSA ? Many 1970s and 80s properties have 60A fuses and 16mm tails. What would the incoming cable CSA be in this case and would it limit the upgrade to 80A or 100A which is becoming the norm these days with EVs and heat pumps etc.
16mm ... surprised me too ... :)
Any advice on what to do if you accidentally cut into the outer sheath and outer conductor of this cable with a hacksaw? I'm worried that it could cost a fortune to have fixed.
tape it up if it aint to deep
PS 100k subscribers 👏🏼👏🏼
Thanks but don’t tell everyone… it’s all about learning not subscribers 👍🏻. Massive thanks for the support Gaz
So theres no short circuit protection for incoming cables in the event of damaging the cable?
Of course the advantage of concentric cables is that from a safety point of view if there is damage to the cable, for example if someone cuts through it with a spade the neutral will be contacted first before the line, reducing the risk of electric shock.
The cable to our consumer unit in our house is split concentric and runs under the garage from the meter box on the outside of the garage.
Also prevents the rather terrifying risk of a broken supply neutral in TN-C-S arrangement, where everything bonded goes live and RCDs won't trip! Pretty much guaranteed to break the line completely before the neutral should you plunge into it with an excavator..! Compare that to separate overhead conductors where a tree falling onto the supply becomes a game of Russian roulette!
I always thought ths was called PME, and that the earth at the consumer outlet had to have a seperate earth
The use of a combined conductor applies only to the supply and not to the consumer’s installation. Therefore, except for the circumstances permitted by Regulation 543.4.2 separate neutral and earth conductors must be used within the consumer’s installation (Regulation 543.4.1 refers).
The distribution earthing system is TNCS. PME is the combined protective conductor principle, where the PEN conductor is tied to ground via multiple earth rods from It’s source ie transformer to the DNO cutout. Doing so lowers impedance ensuring rapid disconnection of supply under fault conditions.
(PME tnc-s or plain cable all the same thing )and we have (non PME tn-s and split cable all the same thing )
The cable coming into my house is at least three to four times thicker than the one shown here,with a spiral wrapped appearance to the insulation. Would anyone care to tell me why?
What if you got 3 hot conductors and no other else (1000A at the switchboard)? The earthing and neutral was done at the main panel at the house and the substation was about 100m away. 3 wires in and distributed into 10 consumer-units and earthing of the building. No need to play with these anytime as the janitor was a licensed electrician (job shortage etc. lead to fully licensed janitors, the 30kV unites on site where always maintained by the power company as the may not had the license for 30kV, and to be honest 30kV/110kV is scary as hell).
Out of curiosity what’s the csa of the aluminium conductor?
Looks thinner than I would have expected
It's solid core so appears smaller than stranded. 25mm hybrid is most common equivalent to 16mm copper. 35mm hybrid is becoming more common.
Should have said 35 is equivalent to 25 copper. Cutout max terminal size is 35 in copper or ali
If this is the case how do we have pen fault? If cable was swa arrangement I'd understand that neutral can be broken but in this case even when cable does get damaged I can't see ever loosing pen.
PEN fault can happen at the transformer end - you don't necessarily need a damaged cable to cause a PEN fault.
@@blower1 i understand. In terms of likelihood a fault will sooner occur between transformer and cutout.
When I worked on the street lighting we would get live columns because the neutral /cpc connection at the underground joint had failed but the live /line was intact . The resistance of dry soil was enough to not create an earth rod of the steel column itself . Concentric cables for steel columns aren't a great idea for this reason. TN-S is better .
Where it's jointed to the main they did another video on this the neutral strands are bunched together like in the cut out and can fail at that point causing neutral failure. Or where they connect onto the over head line
So how would this differ in a 3-phase commercial property rated at 125amp/phase @ 400 volt total? Specifically they type of cable and the maximum distance and rating it can carry below the road. Im a domestic spark but am considering a career change to the DNO side of things so any advanced education would be a bonus 👍 thanks
Do these videos qualify as CPD?
I would like to think so 👍🏻
TN-C-S …….[PME…. Protective Multiple Earthing]…… [CNE… combined Neutral & Earth]… = standard Concentric Cable.
_---------------_
TN-S …………[SNE….. SN&E …..Separate Neutral & Earth]… = split concentric cable
in the uk people are freezing cannot afford their heating if thats the case it is possible to get a hydroponics connector board and wire it to that fuse. happy free heating guys (btw this is not advice so dyor please!)
Would u do a video on the cable connections going back to the transformer and the working of the standard UK transformer would be greatly appreciated
There are many different types of distribution transformer setups and most electricians don't have any knowledge of how things work at the substation. Suffice to say it is a huge subject that would take hours to explain fully.
@@schrodingerscat1863 I've got time exactly the more knowledge the better
@@iknowmyfootball3901 Do you know how 3 phase is converted to single phase with a neutral connection. That is your first bit of research, then look at neutral earth bonding and neutral transformers. Also neutral resistors. This will show you how the neutral is bonded to earth at the substation. Because neutral is bonded to earth at that end it is at ground potential so earths bonded at the consumer end are also at ground potential. As I said this is a huge subject and is the sort of thing you cover on an electrical engineering degree. Way beyond the knowledge needed for an electrician.
@@schrodingerscat1863 indeed I do not just for my benefit more for the lesser trained I'm an authorising engineer, it is far easier to learn in my opinion to explain something showing them with a visual demo rather than giving them a book to read
@@iknowmyfootball3901 Yes, unfortunately I don't know of any videos explaining that kind of thing. I worked as an applications engineer then a project engineer for years designing distribution transformers and switchgear so I have some knowledge of this but certainly not extensive. The guys that design substations, the integration engineers are the ones who really know that stuff well.
Interesting to see the line conductor is aluminium and not copper. Why is that; just a cost saving exercise?
Cost and ease of installation. It’s much lighter and bends much easier than copper. Not really a big deal on a cable as small as this but when you get up to 185/300 3/4 core waveform cables, it makes a massive difference
if neutral and earth are the same the wire, how come it is safe to touch earth wire?
Neutral wire at the end of the day is connected with live wire through a load, then does that not mean earth is also connected with live wire or has some voltage?
Potential difference. For current to flow through you and electrocute you requires a sufficiently high enough potential difference across your body. You are standing on earth, so one side is at earth potential, and the other (your fingers) is touching the earth wire..and that is connected to earth which is the same (or nearly) the same as the potential as your feet. No potential difference and hence no current flows.
The key phrase here is "through a load" . There is no voltage on the neutral, there is current flow but not voltage so no potential difference. Think of the voltage as the driving force , this is used up by the load .
@@dennisphoenix1 It's nothing to do with a load. The load can not exist and the person would still not get a shock because the neutral is at the same or close to the same potential as the earth which you are standing on
Draw it out as a circuit diagram and you will see. Currently only flows through you if there is a potential difference across you, and that is nothing to do with any connected load.
Neutral is close to earth voltage, so in principle, you don't get a shock to ground. The load it carries is (almost) entirely irrelevant - there may be a very few volts to earth potential due to voltage drop, but it ought to be very small. Not that people should go round touching neutrals, as if there's a break in the return it will go to full line voltage if any load is connected. A break in the supplier neutral would be even more dangerous, and is the weak point on all TN-C-S supplies.
@@deang5622 the point here is if you lose the neutral and there are connected loads the neutral and earth (cpc) become live. That's what I was saying as that's the issue with TN-C-S . I said in my reply there was no voltage on the neutral.
Why different feed cables, joined neutral and earth and separate neutral and earth?
Older properties may not have a combined neutral/earth system, so if the cable has to be replaced/repaired because of a fault the split concentric cable has to be used.
Concentric is getting trendy in places where stealing energy is common. Love the induction meter .... but just let place for a digital, there are some vintage ones by now.
❤🎉
It's also worth noting that the orange split concentric cable you showed has LSF properties (Low Smoke & Fume) typically black split concentric can't be used inside a property past a certain distance as in the event of a fire, the insulation can give off toxic fumes. This is where orange (LSF) split concentric would come into its element.
Thanks for adding more detail and watching 👍🏻
Not forgetting earth loop impedance are different tnc-s no greater than 0.35 ohms . Tn-s no greater than 0.8ohms
lets be honest everyone pulls the main fuse
That piece of chipboard screwed in at an angle is dreadful.
I'm being stupid here...how is the Neutral not going straight to earth?.. surely you wouldn't dump 240v to earth..or is it that earth is resistive enough to dissipate it?
Neutral is at the same voltage potential as earth is. No potential difference, no electricity flow.
Hands up who calls the DNO to cut the main Fuse seal 😁
👀
The problem with breaking the seals on fuses and meters and not telling the DNO is that the customer may well get charged at a later date for replacing them.
@@Dooguk I have sealing wires, flag ferrules and a crimp tool. I always seal back up when I'm done, mainly for safety reasons as a lot of older properties I've worked in have a cutout at a low level, often in places where little hands can get to.
Quick question then, my fuse doesn't have a number in it so how would I know what size it is and, if it's smaller, how would I know if I could upgrade of I needed too?
Thanks
Default to 60 amps. You can contact your energy supplier 👍🏻
It’s not as simple as just upgrading the DNO fuse. Typically, if you’ve got a 60amp service and you want, say, a 100amp service, the DNO may need to upgrade the whole cut out and possibly the incoming service cable.
Given that the fuse isn't regularly blowing then it doesn't sound like you need to upgrade it.
@@deang5622 planning on an extension and we have a 14 way CU that is way beyond what the calculation says it's supposed to be, although i can't remember the calculation but it was way way higher when i checked
@@therealdojj I would not expect an extension to justify a supply rating increase. Its about consumers and people. 2 people in a 7 bedroom people will use about the same as 2 people in a 1 bed. I know of a private castle on a 60A supply.
looks like you're using an oversized laptop charger cable to power your homes on that side of the pond )))
So how would you manage to pull that fuse not under load?
Isolate the power at the consumer unit 1st
Wish you are my tutor
The inside of that meter box is aesthetically horrible. What a nasty way to mount the supplier fuse.
Surely anyone that knows what SWA is, knows that it’s not what feeds a house ? 🤷🏻♂️😂
Not college learners 👍🏻
@@GSHElectrical fair point 👌
RIP other phases :(
No wonder ppl use fossil stoves in third world countries when they dont have access to 3phase.
most european countries got 3 phase service as standard. So to my place, its got a 230/400V 3x63A mains The stove want 11kW total with all hobs and oven on. The oven allone draw 4 kW. I only got three real 3phase consumers, the water pump, the drill press, the air compressor and a utility red CEE 32A socket at the backyard. The DNO run a TN-C-S here. A local earth stake is installed (its mandatory). The incomer is 4x25mm² aluminium.
European wiring and service panels always seem super sketchy to me.
Pme
Terre is pronounced like tair
Who did that job? It looks awful!
Cut out installation is 100% correct .
DNO cables are no longer run in cavities on new builds the box is a flush box and the cable entry is at the front with a board used to reduce bending the cable.
That is poor installation of cutout ,they should be embarrassed.
Cut out installation is 100% correct .
DNO cables are no longer run in cavities on new builds the box is a flush box and the cable entry is at the front with a board used to reduce bending the cable.
@@j.f5212 I was talking about the angled lump of wood the cutout was mounted to instead fitted to the back piece .looks crap .
@@raychambers3646 it's done that way to prevent cable damage. It is a functional piece of equipment and doesn't need to look good.
@@JohnSmith-jk8mt well it certainly doesn't look good .
Oh stop waffling and repeating yourself and just get on with it ! This type of video is so difficult to watch as people start losing interest.