EARTHING a SHED or OUTBUILDING - TT - TNS - TNCS - IMPROVED AUDIO
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- Опубликовано: 24 фев 2022
- This video is a re-release of an earlier video in which some viewers experienced audio problems.
There were a small number of comments that the audio was too low and sometimes only the left channel worked. Strange - this was a brand new microphone.
So, the audio has been rerecorded using the old microphone and hopefully, those viewers that struggled to listen before will now hear us booming out. Do let us know in the comments if all is well.
With more people working from home now, here at LearnElectrics, we have been asked many times about converting a shed into a work space or work cave as some call it.
The electrical supply to such a work space, shed or outbuilding will need careful consideration as will the earthing arrangements.
It is not just a case of hammering an earth rod into the ground and installing any old cable.
In this video, we will show you some common scenarios and solutions to help ensure a functioning and safe installation.
This video is No.124 on our RUclips channel where we have videos on a wide range of electrical topics.
To see a full list of all our LearnElectrics videos, click on the link below.
/ @learnelectrics4402
You can also view all our videos by typing LearnElectrics all one word into the RUclips search bar.
Always work safely, electricity can be dangerous. If you are unsure, stop and seek advice.
This video is provided for guidance only. Every electrical situation is different, please check and ensure that you are applying this learning information to your own individual circumstances correctly and safely. If in doubt, stop and seek competent advice.
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You made another video to correct the voice. Your sense of responsibility about the quality of your channel is admirable.
Well, that's really good of you to say that Sajad. Yes, I do feel a sense of responsibility.
Thanks for the feedback, really appreciated. Dave.
Your videos are very detailed and well presented! It's a great archive that people can access at any point and learn from a real electrical instructor. Thank you.
Glad it was helpful, great feedback. Much appreciated, Dave.
Before I do any new work which I didn't do earlier, I search for your videos. This is one of them
Thanks for the support, appreciated. Dave.
Audio is great now. Learned about the different grounding methods. Thanks!
My pleasure Kurt. The new microphone is now in the bin and I've gone back to the old one. Dave.
Good information. Many Thanks
Thank you Pedro, appreciated.
These videos are just an absolute gift to life! Brilliantly explained and straight yo the point.
Can you please do a video on fault find testing for a switch line on a lighting circuit.? Thank you
Lincoln
Lincoln, have a look at this video.
LIGHTING CIRCUIT FAULTS on the link below
ruclips.net/video/S1Tzr5VX8-Q/видео.html
There are also two more lighting circuit videos to be published very soon.
Thanks for watching. Dave.
Fantastic explanation 👏
Glad you liked it, thank you Craig.
Great explanation as always . Would be interesting to see how to install , test the earthing rod for the shed and how to supply the shed from the main building if I have TT . Cable size , buried etc . Thanks
Good idea for a video. Its on the list now. Dave.
Very useful video! I have wanted power to my workshop shed for some time. What are the rules in 2023 with regards to protecting armored cable as it is laid to the shed? I was told that you have to use different gravel to indicate power cable. Does this always have to be a trenched cable or can it be run above ground?
Recommended 500mm deep. Marker tape at about 300mm. It can be run above ground as long as it is visible and away from damage (strimmers, lawn mowers etc.) Hope this helps. Dave.
excellent sound clearly and load
Thank you Mohamed, Thanks for watching. Dave.
Great one
Great Michael, thanks for the feedback. Dave.
Thank you very good video
Great. Glad you found it useful. Dave.
Aah the old extend the PME debate. When I had power put into my garage, I saved around £100 running 2 core 6mm SWA and making it TT, from installing 3 core 10mm SWA. There is also the issue that although the earth bonding can be extended using the 10mm cable, the equipotential zone isn't. If there is a danger of being able to touch the extraneous metal work external to the building, when in contact with the actual earth, then a shock risk can also exist. This was the reason why the earlier EV chargers had to have their own earth rod, prior to the manufacturers revamping the protection circuits within them.
You can of course add an earth rod at the shed along with the 10mm cable, but then it depends on the age of the PME installation and if it is genuine PME or the pre 1970ish version, that relied upon the metallic earth and gas pipes. If you suffer a PEN fault, you are then in danger of having some hefty diverted neutral currents flowing through your cabling from neighbouring installations.
All the various earthing systems have their pros and cons, its just what you are prepared to live with. You certainly braver then me doing s video on the subject.
Thanks for watching and the comments. Dave.
The 1st video was fine .I enjoyed the video twice all good 👍
Thanks Teyron. It was only four people but something had to be done about it. Dave.
Great video dave. One question though, what if the shed or out building wasn’t going to be put on its own circuit?
Say an swa was run from a convenient socket outlet on say a downstairs ring final circuit. Then the outbuilding had only 1 socket outlet installed for instance. So in effect we have spurred into a ring to add 1 additional socket in the shed? Would you export the cpc across? Or just take the line and neutral over then locally (tt) rod the new socket??
I wouldn't do that. I prefer to see each part of an installation on its own MCB. Adding cables to different circuits can lead to confusion as to which MCB is which cable in which room (or shed). Dave.
@@learnelectrics4402 under normal circumstances I totally agree with you. The job in question where 1 socket was spurred off an existing ring final, was only done that way due to the difficulties in running a dedicated supply from the consumer unit (located at the furthest point away from the shed) through a fully laminated house!!! So even though not ideal, and certainly not the first choice of getting power out tho a shed. It was the only viable option on this occasion. So my question still stands, should the pme be exported or should the shed be made tt???
Cheers dave👍
Could you advise the requirements for the example above but with a water supply from a plastic pipe, as this would be the most commonly installed source of the water supply,
Roger, as it says in the video, if there are no earthy parts bonding is not required.
Take a look at this video ...
BONDING PLASTIC and COPPER PIPEWORK on the link below
ruclips.net/video/EYj9mvOfF_w/видео.html
Thanks for watching. Dave.
Is it ok to put in an earth rod as well as using the earth from a TNCS supply, as long as the rod is at least 10m away from any other underground cables or metal services.
Yes, some network operators do insist on this belt and braces approach.
How would I pass the SWA through a metal sheds wall? Should I use a gland and earth it there and go into a junction box on the inside. Or should I use a grommit for the wall and earth the SWA some where else. Also how would I earth the cable on the inside?
The cable will need protecting from physical damage where it goes through the wall. Without seeing the actual set-up, it can be difficult to imagine. I would terminate it inside the building and then branch out from there.
Great videos. If a water supply was going to be added later and the SWA cable were too small, could the use of plastic water pipes be used instead?
I have seen that used and clay pipes. All the regulations expect is that the new cable is adequately protected from damage, that it is clearly identified as an electrical cable and that due consideration is giving to heating effects in the cable because it is inside a containment. To be honest, if you are digging out for a blue pipe you might as well put SWA in. Have you thought how you are going to get the cables through. Dave.
@@learnelectrics4402 It was just a theoretical question, im not actually going to put in a water supply. I do however have a question about exterior electrics. When I moved here an outdoor socket was already fitted halfway down the garden. They used SWA cable buried along the fence. As the socket is near the shed I wanted to extend the cable into the shed to a consumer unit and run lights and sockets from there. My question is about the cable. I cant find any markings to indicate its size. The outside circumference is 19mm when wrapping string around it.
As the cable was previously only connected to a socket, is it safe to connect to a CU?
So the same with a utility extension when pipes that leave the main house and are buried underground then re enter as copper they need re bonded 10mm to the main earth bar?
They will be "earthy" where they re-enter. Dave.
@@learnelectrics4402 Yea I've seen this on so many extensions and have never seen another bond cable installed. Maybe a after thought they didn't price into the job. Also seen lots of oil boilers with no bond even know copper Pipe from the ground on entry. It truly is something that most electricians tend to struggle with. Think it's maybe because gas and water pipes are mentioned so much that people turn a blind eye.
What would you recommend for a metallic shed
I have had to change the TNS 6mm SWA supply to a metal shed to 16mm TT as inspector said that you should should assume TNS is TNCS & not export the earth due to possible PEN failure. This is a very confusing scenario. Go on any electrical forum there’s a lot of conflicting opinions.
Thanks Kevin. This is one of those some do, some don't scenarios and lots of different opinions. Some DNOs permit it, I know of at least one supplier who says that everything must be earth staked as TT, no exceptions. Dave.
What would be the best if it was a metallic shed
A metallic shed is earthy and now we have to consider earth rods etc. There will be a video on this very soon. Dave.
Hi I though you are never meant to export the earth from the house to a detached building.... only to a garage or shed attached to the house. I have a tncs supply in the house and my home office shed at the end of the garden has an earth rod.
I've not heard that one. We always keep them as three wire. Some network operators also like to see earth rods as well as the earth. Dave.
Best use 10mm armoured cable
You won't go wrong with 10mm. Thanks for watching. Dave.
Taking into account the reason you mention as to why not convert to a TT- system for fear of voltage inducement from nearby service under fault conditions.
I HAVE always understood it that we avoid extending a PME system to an outhouse in the event the Neutral conductor breaks.
Do we opt for the likelihood of the lesser evil ie induced voltage from a nearby service, or the earth conductor made live due to the broken neutral conductor at source?
This always has been a should we should we not scenario. Some DNOs say there must be an earth rod, others are less committal. Thanks for watching, Dave.
TOO LOUD tuen it doon.. lollolo only Joshing
Thanks for watching Sean.