Earthing Arrangements TN-C-S, TN-S and TT Identified and Explained
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- Опубликовано: 15 май 2024
- Earthing Arrangements: this video is on TN-C-S, TN-S and TT Earthing and shows installation pictures and drawings to aid with City and Guilds and EAL electrical exams at level 1, 2 and 3. I look at the parts that indicate what earthing arrangement we have and the maximum external earth fault loop impedance of the supply authorities cable.
🔵 Playlist - Earthing Arrangements TN-S, TN-C-S and TT • Earthing Arrangements ...
= 🕐 Time Stamps - Cut to the action 🕕 ==
00:00 - UK earthing arrangements explained
00:09 - TN-C-S earthing arrangement
00:36 - Supply authorities cables
00:44 - Pen Conductor
01:30 - PME
01:53 - Solid link
02:28 - Maximum external earth fault loop impedance for a TN-C-S system
02:36 - TN-S earthing arrangement
03:00 - Supply authorities cables
04:10 - Maximum external earth fault loop impedance for a TN-S system
04:20 - TT earthing arrangement
05:01 - Overhead supply
05:10 - Earth electrode
Was requested to upload it with better sound... I tried.... I have a new microphone coming I am trying to improve my uploads GSH Electrical.
Videos are training aids for City and Guilds (C and G) and EAL courses Level 1, 2, 3 plus AM2, AM2S and AM2E.
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Amazing
Hi. Thanks for the kind words GSH Electrical
T - Terra (ground)
N - Neutral
C - Combined
S - Seperate
TN-C = Terra Neutral - Combined
Earth and Neutral share the same conductor (2 wire single phase)
TN-S = Tera Neutral - Seperate
Earth and Neutral have seperate conductors (3 wire single phase L,N,E)
TNCS = Tera Neutral Combined Seperate
Starts out with combined neutral and earth, then they are seperated, ie from Minisubstation to Meterpanel combined earth and neutral (2-wire single phase) then then after meter panel to house DB neutral and earth become seperate wires (3-wire single phase)
TT = Tera Tera
Earth at source and Earth a Destination (no earth conductor between source and consumer, the soil is used as the earth return path
4zd re e free dd a oool
@@GSHElectrical hello mate
Do you guys train people to become electrician and where are you based
T - Terra (ground)
N - Neutral
C - Combined
S - Seperate
TN-C = Terra Neutral - Combined
Earth and Neutral share the same conductor (2 wire single phase)
TN-S = Tera Neutral - Seperate
Earth and Neutral have seperate conductors (3 wire single phase L,N,E)
TNCS = Tera Neutral Combined Seperate
Starts out with combined neutral and earth, then they are seperated, ie from Minisubstation to Meterpanel combined earth and neutral (2-wire single phase) then then after meter panel to house DB neutral and earth become seperate wires (3-wire single phase)
TT = Tera Tera
Earth at source and Earth a Destination (no earth conductor between source and consumer, the soil is used as the earth return path
Thanks man
No such thing as TNC because you still have to separate them after combining them otherwise it is considered faulty installation. In my country we have combination of TNCS and TT.. So it's a TT like in the video but with earth and neutral combined at the meter. I'm gonna called it TTNCS.
@@IAmThe_RA I would call TNC an incomplete installation; an installation point waiting for a bond. Because TNC has to exist before it can be come TNCS.
Specifically the first letter tells what is done to the one conductor (neutral) at the transformer: T: grounded, I: isolated. The second tells what is done locally with the CPC. N: connected to neutral, T: connected to the ground.
@@IAmThe_RA Sure there is TN-C. It was mandatory in Finland 1930-57 and from then referred until 1989. In TN-C the earth and the neutral are separated at the socket. This is what Americans call a bootleg ground. it is no longer allowed mainly because of the interference it causes. Also the fact that RCDs are required would make it hard to implement as you only can use RCDs at the socket once the earth and neutral are separated.
Sometimes things get messy. My building is TN-C-S with the electricity being rewired ten years ago. By apartment is still TN-C with wiring from the 50s to 70s. so the neutral and the earth are recombined in my consumer unit and there are warnings not to break the connection.
TT and TN are entirely separate, you cannot combine them. If you have copper connection from the CPC to the transformer it is TN. Most countries require a ground rod with TN-C-S. UK is an exception. In Finland 20-40 m horizontal rod is used or the rod is built to the foundation around the house.
The problem in loss of the PEN-cable is not the loss of protective earthing but that the protective earthing gets the mains voltage. Any grounded case will have the mains voltage.
This is great,very clear explanations.I wish i had you as my teacher at college.
Excellent piece of work.
Hi. Many thanks for the support GSH Electrical
Thanks Man! Great Video. Nice explanation.
I have a hybrid setup that looks like both the TN-C-S and TN-S. There is a CPC that goes into the cutout as well as there being a copper braid that is tabbed (bent back slotted T shaped clip) that secures it to the outer (lead) metal of the incoming supply. There is also a third 16mm that goes off to the CU. All three CPC's join in a block with a PME sticker on it.
Absolutely brilliant - thanks for this!
Thanks
Good video mate need to get this for my 2394/95 exams cheers Craig 👍
This was a great video, easy to understand diagrams and explanation. Thanks!
Thanks 👍🏻
Your channel is great.
Really like the way its presented...well done. An excellent channel.
+Christian Williams
Hi. Thanks for the kind words GSH Electrical
Christian Williams
Teachers pet
Any chance you could explain the IT network earthing as used on ships etc
I think I finally understand the differences between TT, TNS and TNCS :-)
Thanks for commenting and watching 👍🏻
Is it allowed to PME a TT system ? I know that some sparkies I've worked with will do it on the understanding that the pole outside has an earth running down it !!
Thanks for your sharing 👍
Thanks for a great video
Thank you very much. I have TN C-S system in my building, and a 3-phase lift motor with control panle in the sixth floor is connected properly to the system as you described and there is encased electrode that is conected to the building structure and to foundation sticking out in the elevator room can I used as earthing for further protection and ground the control panle and the elevator motor to it.
Great video Gary, will this be a hot topic in BS7671 18th Edition Amendment 2 and TT systems more common .
Thank you, brother..
No problem
What a legend teacher amazing
Thanks 😊
Thanks for the video =)
Thank you.
Finally if i had your knowledge id be complete
Finally, someone explained this by showing the colors of the cables :)
Thanks for commenting Gaz
Can you explain the Space Shuttle earthing system?
Just in case I need to travel to ISS and electrician gets sick (he may have the doctor's sick leave), I would have to replace him on the journey further to Mars, so I need to know how to fix the broken PE line, especially being under constant Martians attack from 4 sides.
Love your videos 🙏
Thanks 👍
GSH Electrical, just a quickie... does GSH stand for Good Sense of Humour Electrical? Same initials as my son 🤪
Thank you!
Thanks for watching 👍
What'x is Max Ze on TT systems?
And as the Ze could be quite high on TT systems due to consumer being far away from the local distribution system, I think that the Ze could even be 20 Ohm or so for example. So I(f)= 230÷20=11.5
Which is likely not high enough to operate an overcurrent device and protect someone in case of a possible fault occuring!
So it seems, in TT systems only RCDs will be effective to pretect sm not the normal overcurrent devices.
And you succeeded sir.
You could also mention that the max Ze for the TT system is 200 ohms.
I'm completing the 2365 in a 13 week block. Quite intense at the moment. Any advice for me? Great videos btw, has helped me a lot!
Hi. This book on Amazon is worth having “5357 city and guilds book 1” thanks for watching my channel have you had a look at Joe Robinson Training on youtube 👍. All the best Gaz
Was waiting for the tt max ze, only reason I watched. Otherwise great video
www.voltimum.co.uk/articles/q-day-concerning-tt-system-earth
Thanks for watching Gaz
Thank you sir it helped me much
Happy it helped 👍🏻
thank you
Which one are we most likely to come across in domestic properties and flats?
Hi. TN-C-S. thanks for commenting and watching Gaz
The Authority earth on my electricity supply is wired to my earth which is a ground stake. Is this correct please.
On a tt system would it be 16mm main earth and 10mm bonding
Thanks
Hi. On-Site Guide Section 4 page 49. All the best Gaz 😁👍
The earth return path within the supplier's cable of a TN-C-S system is the? A. Earth conductor B. Cable sheath C. PEN conductor D. Installation earth electrode
Sir l am from india you are best sir
pankaj rajput thanks 😊 🕺
5:16 I didn't understand this part. Why the impedance difference is high and the solution is so?
Thank you, but why are TT arrangements more economical then TN-C-S (4:49)
On an overhead wood pole line an earth cable would have to be buried alongside the poles. Its a lot more digging and an extra cable that would be heavier than the overlead ones used for supply, for a long reach to a consumers premises it wouldn't be worthwhile. RCDs are a lot cheaper than a long stretch of supply grade cable.
Have you come across installations where there appears to be a situation of the supply being a hybrid of TNS and TNC-S where there is both a PME earthing method AND a braided earth bond to the outer sheath of the incoming supply.
In this instance - is is possible to choose to use it as a TNC-S or TNC or must you choose the TNC-S earthing restrictions.
Hi. I have come across this many times and I have images I show in my classroom presentations. It’s an original TN-S system that has been up graded by the supply authority to TN-C-S. If you’re in any doubt always call the supply authority’s from confrontation of the earthing arrangement. All the best and thanks for commenting Gaz
U mentioned a 20 amp fuse in the cu...can u elaborate plz gaz....cheers
Hi can I have more details please... I produce this video along time ago. Thanks Gaz 👍
@@GSHElectrical I didn't really understand....was around the 6 min mark..... cheers
Sorry think u maybe meant 20 less
Why can't you set up the TT one as TN-C-S? Is it because the neutral from supplier isn't earth periodically on the grid i.e. PME?
Hi. It’s because the supply authorities haven’t Earthed the neutral along its run. If you therefore use the neutral as a combined neutral/earth and losses it then you have a line earth fault in the installation the metalwork will remain live creating a massive risk of shock fire and explosions. Hope this helps Gaz
@@GSHElectrical
Hello. For the TT system, some where upstream the Neutral Cable must have been earthed at the Transformer Neutral, which render it the TN-S or TNC-S system. Because the Supply Authority (SA) do not earth the Neutral along its run (i.e. PME), so the SA will ask the Consumer to make a TT system. Is my understanding on this correct ?
Is there a length limit in the Neutral Cable run which makes the requirement of PME on the TN-S or TNC-S system ? Else the SA will require the TT system by the Consumer ?
@@kettaiyong2959 very good questions, unfortunately not answered.
Can you combine tncs and TT together in the same met?
That's how we do it in my country and I think it's the best if you consider all the unwanted possibilities that could happen. Chances of your installation loses both N&T is half less than any of the arrangements shown in the video.
I am confused about what you are talking about at 4 mins regarding a 20 amp protection for what exactly. Thankyou.
In-house fuse is 20A gauge smaller than the Outer supplier's fuse to protect the outer fuse. When a short circuit happens, only the fuse in the house main switch is burnt but not the supplier one which is generally not accessible to the public, including the electrician you get to fix something. Only the power supplier can replace it.
I failed my unit 3+4 exam eal(band) any advice or subjects to focus on
At what level was your exam... level 1, 2 or 3...?
do a video on what we have here.. IT power delivery and power grid.. no N conductor at all.. no connection to ground.
wonder if TN-S and TT could be combined in the same installation ?
Here we have like TNCS+TT. It's like TT in the video but we combined N&T in the meter.
@@IAmThe_RA Then it is TN, not TT.
Sure you could have parts of the installation in TT but I see no point with TN-S. If you have TN-C-S then you could have the EV charger as TT to prevent PEN-faults (which are especially dangerous with EVs as there is a big metallic car standing on the ground.)- IN TN-S PEN-faults are not an issue.
These would be brillaint split into 3 clearly named shorts!
What is the purpose of the local earth stake?
In a TN-C-S
Can you change a TT supply to a TN C S supply
Not without allowence from your supply company. They choosed TT-system to keep earth fault currents away from the neutral line.
i have a mock test tmr 🙂
Terre is pronounced with one t. I.e. "te long r e"