Broken Pen Conductor - What’s Going on Inside a TN-C-S Cable Joints. PEN - Protective Earth Neutral
Me and Joe look at a modern 400 volt cable joint to 230 volts supply for a TN-C-S (TN C S) Earthing system. We see how in new cable joints it's almost impossible to lose the combined neutral and Earth connection. We see the Aluminium line conductor and how it is connected within the joint as well as two different ways the combined neutral and Earth conductor can be connected. The broken PEN conductor (PEN - Protective Earth Neutral) it currently a hot topic in the electrical industry with older joints failing across the UK.
See what’s going on inside a cable joint.
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On every CNE joint now we install a copper tail out of each joint called a supplementary earth. If the cable is a radial circuit it will have an earth rod installed on the pot end. If it goes to a link box to tie up with another piece on network, in theory it has 2 neutral/earth paths
Here in Finland we use TN-C-S everywhere, but with supplemental earthing at the property (can’t remember the regs of the top of my head, but it’s something like a 16 mm2 around the perimeter of the foundation with a 20 meter branch following the incoming) due to our horrible earth resistance. But all feeds are taken to a distribution point somewhere, either the transformer or a sub panel, where it’s fused down for the single feed to a property. PEN faults are of course an issue, but they are extremely rare and most smart meters these days have PEN fault detection anyhow.
Thanks for your detailed comment it’s very much appreciated 👍🏻. It’s possible we are following Europe’s lead with foundation earth very soon. All the best Gaz
Good video guys, useful to see this stuff as its rarely seen and helps the understanding of earthing systems just that little bit more.
Top Guys! You both really are quality. Love the uploads 👌
This channel is awesome I have learnt so much thanks guys
Excellent video, thanks guys. That is a very tidy joint.
Really enjoyed this video. Anything upstream of the cut out seems to be a mystery that is never talked about so this explains a lot. Thanks for sharing.
Great video! Entertaining and informative!
Very nice well done explaining it and actually bringing a visual aid - top man that Mr Hatton👍🏾
Very informative. Thanks
This stuff is GOLD ... keep it coming.
Over 500 videos on the channel 🦾👍. 😁
That is unbelievably neat!
This is wave con or wave form. The wave gives you the slack to gain space to get to the cores. Modern joints should have solid earth tail bought out approximately 1m long. Solid to stop water tracking if it was stranded. The 4 core version for tns does unfortunately have an aluminium neutral core. Every 250m a straight joint will be required which services can also be bought out. Runs should be kept 350m or less generally. Most commonly used in 185mm2 or nowadays 300mm2. The older cables 1970s to 1990 was consac (concentric solid aluminium core) it had 3 solid paper insulated cores with a solid aluminium extrusion neutral coverd in Tar then pvc sheath. The tar was supposed to self heal any pvc damage but never worked. The aluminium powders and fails. The wave con you shown is reliable but if a damage occurs and is left or back filled the aluminium will powder up but unlike paper insulation the xlpe will stretch and allow the cores to buldge and the classic sign is low volts as the powder Ali is high resistance.
Great video guys. And I must say....as an electrician of 20 years, running my own business for the last 12, of all the KZhead electricians, you guys are most worth a watch. I still pick a few bits up here and there from you. Quick question: using the method of jointing in this video; if used through out its run......I don’t suppose the system could be considered PME?
Dear GSH Electrical Thank you for all the amazing content for past couple of years. I have seen all of your 444 video's last month. It was very nice to see how installations are build and tested abroad. Myself coming from the Netherlands, we do it quite differently with more PCV conduct so wires/cables can be replaced without taking down the walls. From the testing perspective I have learned lots of you! And whatever happens I will allways be greatfull.
You need a medal 🎖 for watching all those videos... massive thanks. Gaz 🦾
@@GSHElectrical Where can I collect mine ? It was a challenge watching so many videos in a month ;). Went through so much advertising haha !
Some of the first waveform cables has aluminium neutrals. One little pin hole in the insulation and the water gets in. The neutrals then get pitted and causes them to swell. You could easily find the fault when digging out as the cable looked like a snake had swallowed an egg. The old IPC connections used to fail and go open circuit all the time too. Good video!
Neutral faults are theeee worst 🤢 and always on alpex as you mention it was rubbish cable
Very interesting. Great video, thanks.
The aluminium connector on the cws will not cause corrosion as the shell is filled with resin therefore no moisture ingress thus prevents corrosion. The resin used is polyurethane
Had the system lose the PNE connection, due to the cable having the copper being stolen in the substation by thieves. The losing phase went to over 300VAC, blowing a lot of stuff on it. I saw the voltage rising, from the UPS warning of high mains, so powered off the house at the breaker, and then on measuring the other 2 phases saw this and turned off the building to protect the installation, then called the supplier to come fix the failed neutral. Lot of the neighbouring houses and shops lost all the electronics and electrics from the overvoltage. Took around 6 hours to repair in the substation. Next weekend they struck again, and again 6 hours, but this time they replaced the doors with heavy steel armoured ones. They got around 100kg of copper total for both times, but caused a lot more in damage.
Actually this could go up to 400V in a european three-phase system. Depending on the loads that are connected between the lines and the neutral/PEN. In case of a broken PEN the connected appliances behave like a voltage divider. This can also change, for example if someone operates the light switch, the voltages will change every time because the person is connecting or disconnecting a load. For example: A 20 W Soldering iron connected to a single phase circuit between L1 and neutral/PEN, this is a resistance of 2645 Ohms. On a single phase circuit connected to L2 I got a heater, 3680 W (14.4 Ohms). Both are on different lines, but both are connected at the center point of the star circuit, and that's the neutral or the PEN. If the neutral/PEN breaks, these loads act as a voltage divider. In that case the heater will "see" 0.2 V, and the soldering iron 398.8 V.
@@Marcel_Germann It was 300VAC, more from a mix of around 200 differing residential loads, so the biggest load was the safest. Loser was the corner coffee shop, which lost all the ovens, the coffee machine and the point of sale, along with most of the lighting and displays, as they were on the lightest loaded phase. 50 plus water heaters of 2kW were more than enough to drop that phase down to 70VAC, and they would not cycle off either as the heat input was likely lower than the standing loss, or they were cold from water draw. i have a number of large volume MOV units connected across the line to neutral, and similar to earth, so that if the phase rises high enough it will trip the RCD from imbalance. As the local board has a really good ground connection, thanks to a massive earth mat for the building, the building was probably acting as the local return path and balance point, from the water pipe bonding on all the other connections. I was not measuring phase current, just voltage WRT neutral, but likely the earth bond had a significant current flow. Lucky that is a 25mm2 copper strap and 32mm2 copper wire.
That's why implementing 'conducrete' bedding around the substation earth mat is a good idea.
Great Video and insight into jointing, I was watching a video about earthing systems from John Warn and he was saying that a lot of TNS Systems are actually TNCS in reality because if there have been repairs in the road they would do the repair with multiple earth rods so the earth and neutral were no longer separated. Interesting!!!
TN-C-S has two variants, namely Protective Multiple Earring ( PME) and Protective Neutral Bonding (PNB). In both variants, the consumers earthing conductor is connected to the neutral at the head. PME has multiple earth stakes along its route, but PNB does not, and PNB can be earthed at the consumers position rather than at the Tx star point. PNB also typically serves just one installation but can serve more. So, PME is always TN-C-S, but TN-C-S is not always PME (being PNB). The purpose/point of PME is that in the event of a broken PEN conductor, an installations neutral current can flow down through any extr.c.parts and through true Earth back to the Tx (and helps limit touch voltage in the installation), so if they're not using multiple stakes, are they then NOT providing/supplying PME, i.e. it won't be PME? Re clamping the concentric cables neutral to the neutral in the joint. Are the two clamp positions not about about ensuring that the load is applied to the supply neutral equally? He's split the neutral into two sections, so if he just clamped on one side, he's halved the ccc of the neutral at that point - akin to e.g. terminating only 4 strands in a 7 strand conductor. So by clamping on both sections, he's using the full neutral ccc (rather than it just being about redundancy or belt-and-braces). Re earthing the neutral at intervals, somebody drove a car into the supply cabinet on a street near me a few weeks ago, so the cabinet was renewed and they drove in a stake. A few days ago, another one was moved, and they also drove in a stake - which seems pertinent given it's a PME system, not PNB.
Great comment 🦾
Interesting comment, So are you saying the joint in the video is actually a pnb arrangement, which doesn’t have a direct connection to Earth at the joint? Which is a sub division of a tncs system. 👍 are you a jointer btw?
@@gbelectricks I'm a sparky, not a jointer. All the info needed is in Guidance Note 8, along with relevant line and fault current pathway diagrams. For any detailed technical info, you can ask for free on the IET's Wiring & Regulations forum, found here: communities.theiet.org/discussions/viewcategory/1037
I believe I went to a job recently which was PNB, the servicehead had a separate earthing conductor attached to the incoming supply which was obviously installed by the DNO.
@@davidb3537 the "earthing conductor" runs from the supply means of earthing to the MET, both on the consumers side. The earth wire from the neutral/earth connection down to Earth connects to a stake/plate/etc, but I don't know what that conductor specifically is called (DNO supplies are something sparky's don't get involved with). How many installations are supplied from the Tx, typically apparently it's just one? As a starter, here's a thread on the IET forum that refers to PNB; so you can search for more threads from there to get a better understanding of it (the thread also refers to PNB as TN-S (not TN-C-S), just to complicate matters): communities.theiet.org/discussions/viewtopic/1037/26775?post_id=146414#p146414
A nice bit of information 👍
Excellent info. Thanks.
very interesting! keep up the good work!
the joint shown in this video is old tech now, the phase connectors we use now are fully insulated and insulation piercing so no need to even strip the insulation 👍
@@markrainford1219 they did with the first type years ago which only really became apparent years later but they've been revised a few times since and are now very very good
Agreed
@@markrainford1219 We use them in Oztralia.
Really intresting subject can you update a video showing what they do now. Great subject
Don't suppose you would consider doing a video on exporting an earth. More to do with caravans and why we could not use an ev, or open pen fault devise. We know about 50 v touch voltage and ev is 70 touch. Millions of people go to ebay buy a 13amp conversion lead to attach to a 25m orange cable to keep caravans and motor homes powered up. At camp sites we know its tt hook up. So would it not be safer to use an garo or viridian open pen device or is it because its not in the regs. Surely they rushed through a change to 722,but why not 711.
Great video guys very interesting
Love it lads
As a wannabe old man Spark, these videos are awesome. Very interesting channel such a shame your college is so far away from Cornwall.
Very good video, don't often see the supply side of electrics. Have to admit, with the title of the video I almost didn't click to watch it. I assumed it would be just another general explanation of the risks with PEN systems.
This is why I miss working in FE college's. A cracking example. 👍
I recently had a new Gas and Electric Smart Meter fitted in to my property but this ended up having the DNO come out to dig the road up. They found a faulty joint down my street causing a Voltage to travel down the incoming Earth at around 1.4 - 1.6v, this was also checked at a few lamp posts and each one had a voltage on the Earth. This fault was only discovered when my installer placed his Continuity Bonds from the incoming gas supply pipe (behind the Shut-off Valve) to the internal pipe work, on clamping it created an Arc. When the old Gas Meter was fitted the Anaconda (flexi-tube on the Meter) use to get warm to the touch but cool down when Gas was flowing - It had been like that since I'd moved into the property and i can only imaging the cause to be this small Voltage coming from a damaged joint in the Street.
There is a relatively famous incident where the gas meter was so hot it melted a jacket which fell upon it. The neutral current from a number of other properties in the area was flowing to earth through the gas meter, a problem caused by most the other properties in the area having replaced their water and gas supply pipes with plastic, and probably a dry summer making other earths less effective. This instances of this issue is growing fast at the moment, partially because electricians are using clamp on meters to look for earth currents and the actual cable joints in the road are getting old and suffering from corrosion.
Oh how I laughed at the Hatton joke ...twice ! 😉👍 On a serious note a good informative vid. Thanks 👍
Sorry about the edit 🤦🏻♂️
I thought the other purpose for spiking the PEN conductor was to keep the extraneous and exposed conductive parts within the building it was supplying at the same potential as true earth. If the PEN conductor is not referenced to earth will this not give rise to potential differences on longer cable runs
On the main 3 phase cable that you described you said there was no need to joint on the conductor. How do they joint the main cable when it runs out of the length that is on the main “drum” coming from the substation. Or do the DNOs buy a cable that is long enough to go from the sub station to the new installation so that there are no joints needed in the main cable? What happens when the “ JCB Digger” accidentally cuts through the main 3 phase cable? How does the DNO joint that?
Relevant document is Electricity Networks Association (ENA) G12. Basically it sets out recommendations for earthing of neutrals on PME systems 20ohm or 100ohm rods are specified . For example a network branch consisting of 4 dwellings should have an 100ohm rod at the end of the branch. 2 dwellings on a branch less than 40m don't require a rod. Etc etc Cheers 4 the vids as always!
Thanks for your input 🦾
Another great video thank you guys, I never learned anything about this when I was at college back in the late 80s so I found it very interesting and useful. Just one question though were you say it is important to have the join made with the same mettle to avoid the mettle for damageing each other? Surely the same will apply when we use crimps IE copper conductors with an aluminium crimp? Or is this another miff?
Your crimps are tin plated copper for exactly this reason.
Interesting stuff 😎👍
I have passed some open trenching where the network has been working on supplies and inserted earth rods but just recovered them with earth when back filling and never installed earth inspection pits...
quite normal, they do the same in this area, throw the rod in along the trench before backfilling (SSE territory)
I have seen 1 or 2 houses where the DNO has put an earth rod in when moving a supply and run a 25mm earth cable into the bottom of the cutout connected into the PEN terminal
Yes, also very common with larger TN-C-S services, you'll often see an additional 25 or even 35mm black conductor strapped to the wavecon cable (the 3ph cable Gary demonstrated in this video) that goes back to one or more earth rods along the trench
I have seen western power my local dno do joints on faults and what they do is they have a medium coil of copper wire that they tie one end onto the earth conductor and the other end comes outside the joint housing and lies on the ground as a way of converting to PME
Just had mine upgraded for a EV Charger. Interestingly they've installed a TNS main cut-out, from a TNCS main 3ph cable in the street, so my neutral and earth are just connected in the street. Luckily I emailed them to confirm this so my EV Charger complies with the true TNCS System.
I am from the Caribbean ...I went to trade school we haven't done that...but I would still love to get some training...do you offer training
So am I right in thinking, even tho they have kept the integrity of the main cable, the one supplying a house is still effectively a joint ? Chances of losing it is very low but not impossible? Excellent video guys, really enjoyed this one
The thing is that if it faults it only affects one house (because we no longer do loop feeds) if it were the "old" system a fault could affect many houses!
yeah but as every connection is tightened up and than encased in resin the chance of a fault in one of these joints is basically zero
That was interesting to watch👍do you think they do a nice neat job like that when they are actually on-site 🤔time etc if so I’m impressed
No they don’t - 🤣
Yes they do. neatness=reliability in service. Plus they often (mostly) work live... so neatness is a safety critical issue also. Edit: from what I've seen anyway... I am sure as with all trades, standards vary between individuals
We are having lots if fails around our late 60s early 70s estate in Oakham Aluminium cables installed on PME system The Insulation gets nicked by ground work and the outer PEN gets serious galvanic corrosion over time and fails under load Usually after 10-20 yrs of corrosion with ground contact someone in shower or other high load causes remaining strands of the PEN to fail often is where prev work on other utilities. 10-20 yrs previously or by householders work Repair involves a new section of copper cable into a sealed joint box our own failed 6 yrs back in pavement where neighbours gas pipe replaced 15 yrs back
Why not add a stake to earth any way. Surely more connections to the ground from the neutral will ensure less floating voltage difference to the Earth itself? The more stakes the better, but still using this new method?
Great video guys, nice to know how the supply system to the house works as regards how the suppilers do it, a lot of electrical contractors and electricians seem to not bother or want to kow about this... interesting to know this...
So modern dno underground network substations which have 185hybrid / wave form or 300hybrid / waveform are terminated in the LV pillar are all pme earthed connected to earth through switch gear at adequately rated earthing capacity. The older parts of the network were there are pilc lv mains there’s a lot of transitional straight joints out on the network pilc to plastic and these would be pme earthed. Some old towns only have pilc LV mains and earthing characteristics are usually tns direct earth.
I have seem pme on old house I rented. It one where the power came up the side of the house and ran around powering our house and the neighbours. And it had a visible spilt off down to a stake
Pole mounted supply?
@@GSHElectrical it's buried down the the street but It does seem to Come from a pole pig around the corner.
Thank you as always for a very informative video. I have heard that when jointing TNS cables they will be converted to TNCS as a matter of course. Can anybody confirm this? As electricians can we rely on an apparent TNS service when considering the loss of a supply neutral (PEN) conductor in relation to the design of an installation?
It does happen particularly when a new 3 core TN-C-S mains is jointed to an existing 4 core TN-S. I don't agree with converting TN-S mains to TN-C-S without at least informing the existing TN-S customers as their main bonding conductors could be undersized for a TN-C-S arrangement. But repairs to TN-S cable should be replaced with and jointed as 4 core cable, but that isn't guaranteed. To be honest there's been so many DNO policy changes over the decades it's a mess and you can't guarantee a true TN-S earthing arrangement unless you're installation is supplied directly from the DNOs substation using 4 core TN-S.
@@18in80 Thank you David
Is that an aluminium bolt on the line clamp so it's all in ali?
Very nice video and something which is not seen very often, it is also reassuring to see a soild method of connection Do you know if the joints on overhead lines are of similar construction I am in a rural location with overhead PME with seperate conductors on the poles, I can see my closet PME earth electrode at the bottom of one of the poles, so they do exist 😁
Overhead now tends to be ABC (aerial bundled conductor) so the chances of losing the PEN without the phases as well is remote. The older single wire supplies (with the neutral being the lowest of the cables) were more of an issue, but overhead it's easier to see any potential breakdowns happening
Nice😎
Great video, being from the USA, how long are those run at the low voltage around an area? We only use the "low voltage" of 240VAC for a few houses (between 2 and 6) here off each transformer, and then the aerial lines or buried transmission lines are somewhere typically between 7.2KV to 14KV that run through each neighborhood. Then neutral is derived off the transformer tap for our 120V and ground is both at the transformer end as well as at each home with ground rod and/or UFER grounds. For example our EV chargers don't use a neutral and only our split phase 240V and safety ground.
Great comment and thanks for taking the time to watch my content. Gaz 🦾
Low voltage mains cables in UK are typically laid in runs of up to 400 or even 500 metres.
In Finland where we also have 400 V system there are 120812 transformers and 2.86 million users. That is on the average 24 users per transformer. This of course varies much and can be significantly higher in urban and suburban areas. It seems the maximum distance to the transformer is typically 600 meters.
Hi Good vídeo I was trying to understand how the dno was trying to prevent a loss of N+E to my house after reading how bad pen faults could be (live metalwork in house etc. My house was built in 1986 any idea what jointing methods were back then?
That depends on the distributor it's connected off. Different jointing methods for PILC (Paper Insulated Lead Covered) from the Waveform cable shown. Almost certainly a PME supply either way.
Old pilc cables contact the general mass of earth through the hessian sheath via the lead. In the 80’s when PME was coming in, jointers would go and bond the neutral to the lead at the extremities of the network with an earth rod in the ground. Jointing methods have never ever allowed the neutral or phase to be broken on service breeches as the joint must be done live to prevent the loss of supply. This goes all the way back to the origins of the electricity network in the UK. A distributor must still earth their PME network at all extremities via an earth rod in contact with the general mass of earth. PEN faults are likely to be caused due to the material of the neutral earth, it was coming in the 80s to install cables with an aluminium sheath, if this sheath was nicked then the aluminium would corrode and cause a PEN fault. The resin still sets rock hard as it provides mechanical protection, it is required by law. There is temporary resin which is used on temporary joints which is flexible, it cannot be used on permanent joints.
Hmm, this comment sort of contradicts the statement that "modern" resin fillers should remain very slightly flexible (is the filler now in fact silicone sealant I ask myself?). Any response to this comment?
@@t1n4444 It's polyurethane resin and it sets rock solid.
@@intelmacs Hmm even more curiouser. (Once watched a contractor fix a cut through underground supply cable using an elongated version of the kit in the clip. Bloke had an audience of interested techies as cables much bigger than stuff we worked with. As I recall there were busbars which the broken cable ends were bolted to. Then cover attached and then back filled with a two part resin in a pouch which was a light green. Capsule was clear plastic so you could see if there were any voids. This must have been 30 odd years ago. Contractor bloke said that this was all he did ... apparently it was considered "easier" to simply "JCB" through cables rather than carefully work around them when laying other services.) Anyway, any comments from presenters?
On a breeches joint which this is they have never cut the mains cores, they would have been bound together with tinned copper binding wire then soldered and later 60s ish weak back ferrules were used right up to 2000s, they were also soldered using liquid solder and ladles. PME systems all have earth stakes at the pot ends. old lead covered cables didn't because the lead sheath was never a conductor but a flexible water proofing sheath. But to avoid it becoming live it would be earthed like any exposed metalwork. When cut away for a joint a temporary earth jumper was fitted then at the end either a lead joint sheath was used or later a copper jumper was wiped across. The tie wraps are not required but it makes it look tidy. But the biggest error outside of thinking PME has lots of earth stakes is the abraded sheath, this joint underground is is 905 guaranteed to fail in less time than it should. 50mm of abrasion in a circular direction is the minimum. The resin wont stick to shiny surfaces, so capillary action will draw in water down the shiny surface and get onto the neutral conductors and rot them away, faster the more current flow on that neutral. Also if the outer sheath gets damaged and allows water in it will run down the neutral strands into the joint. a sticky mastic tape should be wrapped around the live cores of the concentric to stop it there. Note concentric cable is not waved so when you open it up live you need to cut half the neutrals and pull out the live conductor. This would have been a fail if done in a DNO training facility. Cables in roads should be in ducts never in solid ground. Service cables can be found at any depth for 2 reasons, first over time landscaping can either increase or decrease the ground hight, secondly until about 10 plus years ago there was no legal depth for these cables, practice was a spits blade deep but if the ground was hard, pre excavator days, it could be just a couple of inches. Sorry to say but a terrible video because of these errors, 15 years a jointer and 39 in the industry so I do know what I'm talking about. I would advise talking to a DNO and getting some advice from their training department. Neutral faults are rare but the are by far the hardest to locate and the most dangerous to the house owner and their neighbour's. Don't bother looking for any pits for earth stakes on the network they don't exist, they a buried with the joints.
Massive thanks for such a detailed comment and sharing your knowledge 👍🏻
So just to check ,the pen conductor is randomly spiked along the route from the supply transformer?? , or are they installed when they tee off for single phase consumer supplies.. and this Method of ‘connecting or joining “ there is no need for an electrode
Could you please explain how one of the 3 phase cables can be 230 volts, when all three add up to 400 volts? Thank you in advance. Jeremy
great video...now you have done the video there's a few beers worth of copper there ....may as well weigh it in!!!
So are you saying there was never multiple stakes? There aren't anymore stakes installed because of this modern method? Or are you saying there were stakes but no one has seen them?
Most neutral faults come from the cable predating this somone decided it was a good idea to use aluminium for the neutral conductors so all that's needed is a sharp stone to puncture the outer sheath and the aluminium corroded and turns to powder the newer cable can run happily with the copper neutrals wet
Those brass gauzes on the neutral block we don't use those anymore, we have a small brass plate that fits in the connector.
Thanks for the update 👍🏻
Last new build I did a couple of yrs ago they fitted copper rods / tape out of each corner of the joint
Thanks for that message 👍
07:45 But why no galvanic corrosion between aluminium and brass in the same way we get corrosion between aluminium and copper? I guess the idea is that the moisture needed for the corrosion would come along the conductor and the assumption is that there would not be enough to physically touch the aluminium part of the clamp?
You don’t need to put brass with copper to ally in a joint. There is no oxygen in a joint that’s been filled with resin so how will it oxidise inside the joint. They say do it because on the overhead it would oxidise because it’s all exposed to the elements and will fail quickly they’re just using same practice for underground
Hello Gary, Came to your channel first to ask, have you ever done a wiring tutorial for Solar Panels and how these are connected at the consumer side?
Short answer NO
@@GSHElectricalIs this something in the pipeline or never ask again :)
Concentric Cable is Feeding Your House 100 Amp Cutout and NOT SWA (Steel Wire Amour) Cable kzhead.info/sun/ZMyJl8N7ln2NioE/bejne.html
is the bolt also aluminium?
Done much like when we complete street lighting branch joints. We don't break any of the conductors.
Are neutral and earth combined like this on high voltage power lines when carried across on pylons?
No neutral or earth is carried on the pylons. Only phases of varying voltages.
Typically HV pylons do have an earth conductor at the top linking all the towers, which are themselves earthed. But this to provide lightning protection for the conductors which are usually just three phase conductors carrying one circuit on each side of the tower, as R.D. mentioned.
@@Richardincancale yes, I meant the supply earth isn't distributed on the pylons.
The three phase cable colours, brown black and grey is the same as the two way intermediate strappers, three core and cpc. Brown, black and grey, cpc. Is there a connection?
yes 3 core and earth cable uses the phase colours, thats why you sleeve the black and grey with brown sleeving when used with a two way so people know its all a single phase. (replace phase with line and earth with CPC if you like :)
I'd have thought they use IPCs on to the phase conductors. It'd be pretty difficult to get your Stanley knife around them without touching the PNE conductor.
Going back to the the day of the dinasores,inside the house they took the earth from the lead water pipe 🤣
Lead = Decayed Uranium.
Used to be the recommended method in the 30s and 40s (maybe even later).
How are they allowed to connect such a small cable (25mm) to the 95 or whatever it is connected too? Is there a fuse down the line? 🤨
The small cable feeding the property goes into a mains fuse and disconnect first. Of course the length of cable cable coming into the house before that fuse is not fused and I don't see how that would be possible. You would need to have a fuse in the underground joint. Of course the feeder cabler itself is fused at the transformer or distribution panel. That fuse would blow if a dead short occurred but they are big heavy duty fuses so don't count on them doing anything unless something ridiculous like 1000 amp are flowing.
I really like Efixx content chaps but..... what if this was a TN-S to a PME conversion?
Great vid thanks for sharing. 🐵
Thanks 👍🏻
They never used to cut the cable to do a joint years ago…also saying historically saying the earth and neutral would fail after cutting out many many faults I can say that 95% of the time it’s always a phase gone not the neutral.
Why do they use aluminium line conductors not copper?
And the reason why it is not staked is the same as it's always been?
When I lived in the country with overhead feeds, they did use ‘real PME’ to earth the neutral at each overhead pole on the way back to the 11kv/3 phase 240v transformer.
@@r.h.8754 Interesting - where we were our community didn’t have mains water, we had our own spring feeding via an alkathene pipe coming down the hill - hence no alternative to lots of grounding!
Can you tell me how best to use 1-pole circuit breakers or 1p+n or in what situations one is used and when the other is used you can also make a video on this topic but in accordance with the regulations
5:06 galvanic corrosion
Oooooopppppsss Who edited this one?????? Still very educational though Cheers boys👍👍👍👍
🤦🏻♂️
interesting
👍
You didn’t take out your first attempt at the video in the edit, or was this on purpose??
Make us look human 🤦🏻♂️.
Sorry guys, apologies in advance . @5.56 if they didn’t break the line conductor, how they installing Aluminium clamp to the line conductor? PS: may be I am missing some basics :(
If you attach a voltage monitoring relay form into your switchboard you eradicate the problems of a Broken Pen Conductor
How much does 100A one cost?
so if you are installing a vehicle charger why don't DNO garanty that PEN is not broken?
Lets talk about the move to foundation earthing then? 😉
Checkout my @efixx KZhead channel for that content 👍🏻
Waveform cable 3 core , you can also get 4 core ! Bottle ends do require earth rod with 16s earth
Finally made sense Don't cut the neutral!
Hey Gaz, how's your daughter?
Thanks for asking - slow progress I am hoping to have her on the channel at some point to up the people that supported her through her journey. 👍🏻 Gaz
Looks a bit old fashioned to me, can’t they just get some big maintenance free wagos ? 😃
Have to stand on them to shut then😀😀😀
@@phoenixfridge1495 😂😂😂
Another interesting observation. You don't have any circuit breakers for the house feed. Here each house feed will have a breaker at the connection to the main feed, say 100 amp or 80 amp. That way if a single house cable is damaged, the breaker trips and doesn't take out the whole street of 15 to 20 houses.
Wow, surprise surprise. Your cabling is different to us in South Africa. Our armoured cable has a neutral conductor. We don't use the armouring for that purpose. It is connected to the neutral of course but it doesn't function as a load bearing conductor. The house earthing will be bonded at the meter box to the neutral, where it becomes the S Part. There is also an earth rod at the meter forming the PME part. Up to the meter it's C. So yes TN-C-S and PME. So yes TN-C-S
The cable in this video is not an armoured cable .
Nobody ever cut cores historically to tap a service on, whoever told you they did is a liar. The earliest connections where plumbed live in ‘T’ joints where the service comes in at 90 degrees to the main
Guys, we NEVER stripped off the steel tape armour and left it in the mud lol! You might have some really rough jointers down there, but here in Scottish Power region, you would lose your job for doing that. You actually cut the armour (which is, of course, an earth) and plumbed it to the lead with a soldered ball wipe hence adding extra earth path and sealing to prevent water ingress. As the lead sheath is your main earth, you would fit a continuity strap prior to removing it. Then in PME supplies you would plumb on a 70mm earth wire to either side of the cut lead sheath and take it through the connection on the neutral. In SNE supplies the earth wire just bridged across. Also, we NEVER cut through conductors for a service connection lol! Imagine if we had lol? People off supply on all 3 phases cause the neutral would need cut too! HSE going scripto for unnecessary live working! We used weak-backed copper ferrules, a good set of grips then soldered using a pot of fine solder and flux. Ah, the olden days... One other thing: the aluminium shear-off the lad used on the CNE is not suitable for use on Cu conductors. It was used when the CNE waves were Aluminium and the service n/e was Cu and it was the service Cu you wrapped the brass gauze around. Using one on a copper N/E what with a different torque and it being unsuitable should never happen. I wonder if he's pranking you or just doesn't know his job? Other than that, good job! :-)
Yeah, unbroken path until a digger appears, then it gets jointed....
Very weird system when you are allowed to install hidden junction boxes with no access and make buried splices. Cable distribution cabinet with fuses at street might be too fancy for UK ;D
I’m sorry but this is complete nonsense. I’m a cable jointer from Live LV up to 33kv. I work on new cables and old paper insulated (pilc) cables. The live or neutral conductors were never cut to do a service joint. They were jointed in the same basic way but soldered with ferrules instead of the insulation piercing connector used today. Also there would be a minimum of 1 straight joint every 250M. Usually more depending on the street layout. You could have 20, 30 or even more joints in the cable before it reaches your house meaning the neutral is broken at every joint with a possible failure point. Some companies use earth electrodes on there service joints but this is not a steak driven into the ground, it’s basically a solid copper wire that comes out of the joint about 1M long that is backfilled with the joint. I think you’ve been a bit ill informed on this occasion
Thanks for taking the time to comment in such detail 👍.
With that being the case Stuart, could you please describe possible scenarios of how the cne of a pen conductor could be lost?
Most common fault on PEN is a cable they used in the 70s-80s. It had an aluminium sheath which is the neutral earth. Any water ingress with aluminium causes erosion which therefore leave loss of neutral. This only happens if it a radial circuit and not tied in with another piece of network
@@sparky9282 Thankyou for your response. You've helped a few things to slot into place. I remember being briefly shown a section of the old pen cable you describe at college. I didn't know it was obsolete or how it failed. It would help if colleges went into more detail on this stuff. Understanding breeds more compliance than do orders.