Types of Earthing System for Electricity Supplies (UK)

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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[hughfowler]

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.

[fredza]

just wanted to say thank you for providing one of the most concise and clear explanations of earthing structures

[thabood]

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*

[leonlt]

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...

[Marcel_Germann]

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.

[paulkurilecz]

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.

[caaaarter]

Your videos are so thorough and articulate the subject very well.

[mk]

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

[darkbyte]

Thanks for explaining the types of Earthing systems, Everyday is a electrical learning day!

[MRubio]

Thank you Mr. Ward even though i reside in the states your vlogs help me immensely.

[johnschroeder]

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.

[thatcolinbloke]

Currently studying 17th edition and the earthing had me baffled but your video has cleared that up, great vid thanks

[mikemercury]

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!

[sjokomelk]

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.

[ElectricBowman]

This is a fantastically straightforward and clear explanation of earthing. Thanks a lot, JW

[DPH]

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.

[randacnam]

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.

[petergambling]

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 👍

[JC-ziqc]

Excellent video, for the first time really understand the three different earthing systems. Please keep up the good work!

[metersocket]

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.