Types of Earthing System for Electricity Supplies (UK)
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- Опубліковано 6 лип 2024
- The three main types of earthing for mains electricity supplies to buildings in the UK. TT, TN-S and TN-C-S.
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I’m an 18th edition apprentice and 3 lecturers have tried explaining this to me. Thanks for the clearest explanation I’ve had. Finally this makes sense. Thank you John Ward.
just wanted to say thank you for providing one of the most concise and clear explanations of earthing structures
Cìâ
nhta çcucu derasunaaq
On cum ma fut
I only have experience where I can say for certain.
1. Only phase and neutral conductors are supplied.
2. No earth rods are installed at the transformers.
3. No earth rods or bonding to re-bar in the concrete is carried out.
4. Therefor this is a substandard TT system.
5. Sometimes earth and neutral are joined together making things worse.
Go watch my Facebook video Samui English Electrician
As they say...a drunk could understand that John...couldn’t be clearer...excellent. Thanks.
What a legend.
I'm doing my level2 electrical installation and types of earthing arrangements is part of the installation methods unit. the diagrams used by the college were usless so thanks for this...
Thanks for explaining the types of Earthing systems , Everyday is a electrical learning day!
Your videos are so thorough and articulate the subject very well.
Thank you Mr. Ward even though i reside in the states your vlogs help me immensely.
A clear presentation style going straight to the key points- a very refreshing change from some of the other vids I have seen! A thumbs up from me!
Hi John, your videos are fantastic. I am currently doing a 2 1/2 week course in domestic installations - my instructor no doubt knows his stuff but dear god he does not know how to teach or communicate.
I have highlighted the most important things for me to learn this weekend and you have addressed two of them in the last half an hour.
Thanks!! :)
*subscribed*
Bless you dude, I thoroughly enjoy watching your tutorials. They're very easy to digest. 😉
these videos are so helpful. I've nearly completed my City & Guilds Level 3 Electrical Installation Diploma and this content is really helping with my wider understanding and prep for exams. I like your style of explanation, thank you.
The explanation at the beginning, about the transformer grounding cleared up so many questions for me, thank you
This is a fantastically straightforward and clear explanation of earthing. Thanks a lot, JW
What can I say John, except you have an excellent way of passing on the concepts in a simple and concise way. Call me a sado but I so much look forward to your articles.....
I commend you on the simple and clear demonstration of the variable systems. Well done.
Fascinating overview of how the UK system approaches electrical safety. I am in the US and I can now see the advantages to our system of having a center tapped neutral on the distribution transformer secondary. The earth (grounding) conductor is connected to the neutral at the entrance to the structure and there is an earthing rod driven at the structure.
In Germany you could find TN-C (older buildings) or TN-C-S (modern buildings) are the most common systems. But sometimes you could find TT, which depends on your supplier. The buildings with TN are fitted with an additional earthing rod for the cable failure you described at 10:48 min. Formerly they used the incoming water pipe, but now the most water pipes are made of plastic and the earthing rod is placed in the ground plate of the house (newer ones) or got a separate rod. And the most building connections are three-phase-current. The three lives L1, L2 and L3 all have 230V measured against N (or PE), but 400V against each other, so you've got two voltages in your system.
In Finland TN-C was also common earlier but after 1989 it was allowed only with a 10 square mm PEN-wire.
@@okaro6595 Same thing here, PEN only permitted if it's at least 10mm² copper or 16mm² aluminium.
Excellent video, for the first time really understand the three different earthing systems. Please keep up the good work!
Your videos are being great help and making it easier for me to complete my electrician course as I am totally new to this field
Thumbs up
What a cracking vid. Looking forward to watching the rest!
Thank you very much for a brilliant explanation.
Just wanted to say a huge thanx to you. Very concise and descriptive and made what seems to be (sometimes) difficult to understand, understandable.
Great speech and great use of visual aids.
Thanx again😁👍
Thank you so much I'm doing my 2391 and I'm dyslexic so need as much help as possible and your teaching is amazing for me very clear and to the point thanks again 👍
Thank you.. your videos are helping me massively with retraining as a sparky.
I really appreciate you doing this for others to learn from :)
Thank you. I've been searching answers about this for long time and now got them from you. I enjoyed your video.
Clearest presentation I’ve seen on this topic.
Man, this is great- I subscribed and liked the video. Thank you very much!
Very informative - thanks John!
Currently studying 17th edition and the earthing had me baffled but your video has cleared that up, great vid thanks
did you make it?
John, many thanks again for an very clear exposition. Well done.
TN-C-S is also the standard for system grounding in the US and Canada and has been for quite some years, except it is common for the main distribution board to have its own ground rod connected to the ground bussbar. The only other difference is that the supply transformer has a 240V center tapped secondary which is grounded and the end taps providing the 2 120V hots.
I think termed as single phase 2 hot wires?
@@johnburns4017 It's more commonly called split phase.
Just found your channel. Many thanks for these videos. Extremely helpful.
Probably the best explanation I have seen. Thank you.
Another great video. Comprehensive, clear and concise.
Here in Norway the customer must provide an earth rod regardless of what system is being used. Even TN-C-S-systems must be connected to earth where the PEN is split to N and earth. So whatever happens to the earthing from the power company, there will be a local, good earth point.
sjokomelk That is also permitted in the UK - however it is not required, so is almost never done in reality.
***** in a T-T system can you bond the earth and neutral at the premises demarcation?
Robert Szasz No, only the electricity supplier is permitted to do such things. Therefore you are stuck with whatever earthing system they provide, or ignore theirs and use an earth rod / TT system.
***** Although sometimes you can call the DNO out for them to convert a TT system into a TN-C-S one, albeit at a cost.
+sjokomelk
Same in Finland, I think we are almost 100% TN-CS.
If you have IT-system, wont that mean that an Edison-screw light socket has its threads live too? Or do you use bayonette mounts?
when he said hello I'm JW.. you most certainly are John Wick with this... You my friend deserves a seat at the High Table. 👏👏👏👏
Thanks John,that was really interesting
Thanks for your detailed explanation. Something useful for those of us in Nigeria
Thank you so much for providing these excellent instructional videos.
We have been "PME'd" here but my neighbour (same phase) is TT. My neighbour's system tripped (the voltage type you mentioned)but her fault also tripped an RCD in our property. Looking at you diagram, i think i can see how this has happened. Thanks you for such a clear explanation.
Clarity at last! Many thanks.
Brilliant and very clear instructional video. Thank you John (liked and subscribed.)
In Australia we have a MEN (multiple earthed neutral) system where the star point of the transformer is earthed and each house is supplied with active(s) and a neutral. At the main switchboard an earth stake is connected to the main earth terminal and a link is main to the neutral terminal. This means that any A-E faults will flow through the houses earth wires then go back on the neutral. If there is a fault with the neutral as well and it is broken then the current will flow through the earth stake to the transformer, providing the best of bot options 1 and 3 from the video.
The best system
That's the TN-C-S system. In Germany is this the most common system too. But only in houses build or modernized after 1973. Before this date TN-C was the common system, with no separate wire for N and PE. You've got only one wire for this, the PEN.
There are some pen systems in Australia but it's not very common and only in particular circumstances
Now the PEN is in Germany allowed only if it is minimum 10mm² copper or 16mm² aluminum. But only for new installations, the old ones made before 1973 succumb to the right of continuance. But only if they are not unsafe, making massive changes (extensions for example) and if they no longer conform with the regulations that were valid during the time of installation. A change of a wall socket, lamp or a switch does not affect the right of continuance.
Great videos John Thanks very much for your time and effort
so helpful. much respect to you sir.
*_Thank you for this rather helpful tutorial!_*
I knew JW was the place to come for this information. Looks to me that in the 'absence' of an earth, the neutral simply needs to be connected to the earthing cable inside the house at the board.
Thanks John. You are a legend!
You are clear and concise greatly appreciated
Very good. Here in Australia we use the TN-CS system but the main earthing point is connected to an earthing electrode via the main earthing conductor and to the main neutral bar on the consumer side via a link which must be the same CSA as the incoming neutral. We call this the MEN link, and the system the MEN system (Multiple Earthed Neutral) as the neutral is earthed via the MEN link and in various points back to the TX star point. The consumer main neutral therefore functions as a PEN conductor. As JW mentioned, we do occasionally get instances of open or high impedance consumer main neutrals and shocks have occurred. RCDs clearly won't open as there's no current imbalance between A and N on the consumer side. There are also hazards if consumer mains are connected with incorrect polarity but RCDs (if installed!) will open if current flows to earth in these cases.
Things are easier when you have only the one system! :o)
Very clear and concise presentation, thank you
Fantastic Video!!! Explained In Simple Terms
As usual always very good and clear. I wish all explanations were this good. Thank you.
😢
Thank you John ... perfect!
Great explanation!! In the USA we have 2 hot wires 120/240 and 1 ground/neutral the grounds and neutrals are bonded inside the main panel. The nec requires 2 ground rods for each electrical panel inside the house.
It's 2 rods if you have more than 25 ohms only with 1 rod. Wrong on each panel board. I for the main, none for others as they are sub's using se-r. Unless it's an outbuilding. Still uses the se-r, but also requires the rod.
In main land Europe it is more common with 3 phases + neutral configured in a star system. 400V between phases and 230 between phase and neutral.
Great video great to understand more about earthing systems 👍👍👍
Thanks! That was extremely well explained.
Thanks a lot John! Very helpful!
Thanks, very clearly explained.
Crystal Clear as always many thanks
Thank you so much to the great explanation!!
What a fantastic video, Thank you.
nice info about GND-earthing
In Denmark the TT system is exclusively used. RCD are required on all installations which supply up to 20A, including old ones that was made before the invention of the RCD. It is the consumers responsibility to make sure a device has ground a connection, and it is only mandatory make the ground connection on domestic appliances.
I live in the UK. Our earthing system is TT. Our house was built in the late 1960s.
Thank you JW 🎖️
Superbly clear. Thanks.
SSE are now installing more and more TN-S systems on new connections work. TN-S is now always used when connecting up metal clad buildings or connecting to the old PILC cables. Funny how everything seams to go full circle. As a cable jointer I personally think that TN-S is a better system. Really good vid by the way.
Very nicely explained, thank you
In Australia, the Multiple Earthed Neutral (MEN) earthing system is used and is described in Section 5 of AS 3000. For an LV customer, it is a TN-C system from the transformer in the street to the premises, (the neutral is earthed multiple times along this segment), and a TN-S system inside the installation, from the Main Switchboard downwards. Looked at as a whole, it is a TN-C-S system. So, normally there will be a link in between the neutral and earth bus bars behind the switchboard, as well as at the local transformer.
Cheers JW
Here in Germany we use TN-Net, TT-Net and IT-Net. The TN is splittet into TN-S, TN-C and TN-S-C. We use normal 3 L Phase, some old houses have only one L Phase. The power cable come in house direct into a big fuse for every phase - at this point the 'Saved Earth' and 'Neutral' go to two difference lines. This place is the exchange point between the power company and my home power net. After this I must install the Watt-Meter from my power company. After this we can install every RCD how we want use ... Most older installation haven't one. For Thailand I not know the situation, we use there an own transformator ...
Is it allowed to make TN-S-C ?
Great video that explains it very well
JW god bless u for such good videos you really helping us to understand electric in easy way and a great help towards my electric course
Mom
I love it. It's like Hugh laurie swallowed the 17th edition. You rock
now it's doctor Ward ;)
Hi thanks for the time to make this video. Natural teaching
If you like this topic , watch a video entitled "EW rice interviews Elihu Thomson " he's the engineer that came up with earthing " and maybe some others around the same time . Go to around 10.27 in the video and he states it was his invention for safety . I like the term you English use "Earthing " ,better than what we in the States use " Grounding " great video ps Mike Holt has good videos on this topic.
Very good explanation.
Thanks for the video content that you provide
Brilliant presentation thank you
Thanks for the video!
Thanks John , This is exciting ,I am starting to understand , may be its the white board but youve just broke a barrier . Before i know it I'll be wiring a plug !! Seriously, the other experts who try to explain should come down to our level and see what its like , its no fun down here ,but you obviously know a few thickos and kow whats required
This is great!!! Thank you very much!!!
thanks for this excellent explanation,
I've seen a few You Tube informative videos but this beats those hands down in presentation skills, clarity, knowledge and video quality. You should branch out into "How to make a You Tube video"!
This video is a great explanation 👍🏻
Great video! Here in Denmark we pretty much only use the TT system. I'm not sure why... but i guess it's because the electric company like the idea that they won't have to be responsable of the PE connection.
Here in Italy we also use TT for houseolds, only industrial use TN, I thik that's because earthing, in that case, is on the customer so if earth conductor fails, the power company has no responsability.
How on earth (no pun intended) can you get proper Earth conduction in Italy with a TT system, especially when for example you live in a rocky terrain? You guys have to drill 30M deep rods or something? :P
very clear and informative. thankyou.
There is a label on the cutout here that says "This installation is connected to a PME system" - so that confirms mine. A house we lived in before had a plate on the cutout saying "PME system" too. However, we also lived in one house where the supply came in from the poles, and that was TT. Our ELCB was a Chilton voltage-operated one.
super informative, thank you
very informative thanks alot
I am proud of you sir thank u it is very help me with my electric course
Great video thanks very clear.
Great info
A Malaysia we follow UK specs most of the time (down to voltage and socket type), though most households here use TT earthing. TN systems are virtually unheard of.
Thanks John
Re supplying outside marquees etc from a TNC-S system - the danger would only arise if that supply came from BEFORE the "C-S2 split. Provided the supply to the marquee etc. is from AFTER the C-S split all would be fine- just like stuff in your house.
MEN is the standard here in Australia. It's a TN-CS system, with a separated neutral/earth bar arrangement, and a earth rod in the ground. We have to find resistance as low as we can get - typically 1-10 ohms. Some sites (Centre of the country - sandy country) can see earthing rods 10-15M in depth. We equipotentially bond everything to stop balance issues.
Good description.
Well Done!
great video, very clearly and well explained. However 2 points. Most of Northern Ireland (rural areas) are still in TT. My house built in 2006 was done in TT. Also when you say neutral is the same potential as earth. Must be remembered that in an AC system half the voltage is carried in the neutral and the lifter you get when you accidentally touch between neutral and earth is worse than live to neutral (or at least always feels much worse!) Overall, well done.
There is another type of Earthing that you could of included. It is called PNB. Normally used for one domestic supply only to a single phase 11kv - 230 transformer where the earth for the transformer is via the neutral block on a 100 amp cut out connected by a 32mm covered copper wire to earth electrode/pin in the ground. Although historic, lots still exist and are in use in Dorset/Wiltshire/Hampshire and Somerset.