Earthing & Bonding - Part 1 : Earthing 

I’ve been sparkling all my working life,but I seem to know more every time I watch one of your videos. Great channel John, keep it up mate.

This is one of VERY FEW sources available and it's clear and concise. Thank you JW

wow great to see this on line!.. been looking for detailed explanation/classroom material on youtube on the uk standards for years.. Thank's John ... keep the good work up..

All your videos are really good! clear and easy to understand. Thank you for your time!

Your videos are informative, clear and concise. Thank you for your time, please keep up the great work I look forward to more of your videos.

Just a quick note of thanks for these wonderful videos.

Thank you for all your tuition. By far the best teacher I know of.

I learn far more in far less time from watching these videos than i did on my courses.

Great video John, I've just started c&g 2396 design course, this video basically shadowed what we did today

John ward, you should be knighted for the knowledge you're sharing. Better taught than college! You have no idea how much I learn from your videos

Excellent clear video once again. Thanks John.

I've found a cure for insomnia. John reading from BS7671 Wiring Regulation. Great video. Looking forward to the bonding vid for night shift week.

Thank you for the enlightening posts John, much appreciated

Great videos John and a beautiful pair of Farnells you have there. Subscribed!

Thanks a lot John ward! You are the best.

Thank you John.

Thanks John , that what I thought , great videos by the way

Looking forward to the bonding video (and if possible could you include an explanation of the situation when supplementary protective bonding is needed on a 17th edition installation please?)

thank you John

thank you very much for your efforts and keep going you are doing great,

John - is there any chance you could consider generators and their earthing issues. I'm thinking of the bonded neutral versus floating neutral issue for generators with a circuit breaker switch. The generator I bought recently has a floating neutral (i.e. not bonded to earth) and the manufacturers (evolution EVO200 engine with GEN2800 generator) suggest earthing the generator to a ground rod. Apparently, this doesn't trigger the circuit breaker in the event of a live wire touching the generator frame.

love that equasion, can save money, makes me look like a scientist when i use it

John your videos on BS7671 are concise and to the point. I have a couple of apprentices that work for me. I use your videos to get across the importance of BS7671 has this never seems to hit home with young ones. I send my play list which is made up of your regulations and testing videos and have them to watch them all and carry out the same lessons on site depending on the level of experience obviously. I feel that at college they have to much theory in classroom and when they get to site they are lost with how to gain the information from equipment and safely carry out any tests necessary. I’d love to see more of the regulations videos. I know you have a lot and it’s brill keep up the great work.

Are both the selection and calculation methods used to determine the protective cable size that connects to the CU, as well as for individual circuits?

I really wanted to be an electrician years ago - but i knew the maths of it all would really get to me , i wouldnt have been able to pass the test(s) on the mathematical side of things, but on the practical side not wishing to sound big headed but I think I am pretty good on it - shame that. I wonder how many other students would make great sparks but failed when it come to the maths tests.

Hi john just like to ask a question im designing acharging cab for ipads and its made out steel and 240v conection does all the cab metal need cpc fitting to all parts

Hi,John. I had strange experience...When I measured Earth fault loop Zs on high current mode(Fluke 1654b)its showed me 0.01 Ohm...,when I did the same measurement,but on Non-trip mode,it's showed me normal impedance- 0.28...for example....Why we have two different readings on the same circuit,on different modes of tester? Can You explain it?

top videos keep up great work superb

In Pakistan, we do all that practically. Awesome explanation.

Thailand has TT 2 wire system with no earthing. Typically KWH meter is overhead fed and visible from the street. If I can connect an earth cable to the neutral before the consumer unit without cutting the neutral, does that make TN-C /PEN ? Would this conform to regs?

Such a great teacher, seems to simplify bs 7671, (the bs in bs 7671 stands for bull shit) love this guy to write an on site guide sort of thing for electricians doing varied work, as we all do, can't know everything of the top of our heads can we, do it JW

Hello John, I need to install a 10 ml cable to supply a 10.5 KW shower. There is an existing cable to the shower but it has been connected to the cooker circuit under the landing floor. Can I utilize the existing cable by disconnecting it from the cooker circuit and extending it to the consumer unit with a junction box or should I replace the whole cable as a single piece?

thanks for the video.but i have a doubt. we can calculate the size of conductor by using those clause but what about the cross section of protective conductor that we use for door earthing on switchboards?

Hi John - should I earth my Tv aerial as I'm about to fit new it seems a USA requirement but not here in the U.K; also acting to prevent static build up with tv view boxes(and against lighting?)

Thx for sharing yr knowledge

cable calc video please. find your videos very informative

I’m sorry I don’t catch, for the value 0.29 \Omega, is it the current from the live cable of the transformer, passing through earth, and back to the neutral of the transformer? What if it’s a 3 phase circuits?

Good video.

Good day John. Thank you for so much insight Can you please upload a tutorial on 3 and 5 heat stove switch

Hj John, porque dizem que o aterramento TNS é mais seguro que o aterramento TT sendo os dois sistemas ultilizando dispositivos DR e disjuntores???

on t-n-c-s in new builds they do not supply any earthing connection at the cutout and the water supply is all plastic is there a need for a stake , and should cross bonding be carried out where plastic converts to copper at the last part of the final plumbing connections ?

any chance you do a video short circuit R1 Rn grate videos mate :)

@johnward, Have you heard of grounding sheets for health benefits. You're supposed to sleep on them. I have my own opinions but thought it might be interesting to hear what you think of them? They connect via a local socket for the connection to earth but the plug for the sheet has a 100k ohm resistor inline so in my mind this would pretty much isolate the sheet from earth negating the health benefits of grounding? Thanks

good video please keep contnue

So a shower is classes as exposed due to the water flowing through the heating tank and elements?

Hi j w what would be you're opinion on a metal lamppost , exposed conductive part or extraneous ?

What of installations where the earth is tied to the cold water copper piping? *edit* Just watched part 2 and you addressed this as extraneous systems bonding.

Hi John may I know how to select cable size and calculate voltage drop formula, thank you.

Good content john i very much appreciate it. you made my life easy for the day, thank you

Shipping containers stacked two high. Electrical sub panel (100a) inside top unit fed by 4 conductors red, black white and green. Should the panel be bonded to the container wall and subsequently connected to an earthing rod?

I noticed that my meter tails to two consumer units are 25mm² however the suppliers earth conductor appears to be 4mm². This seems undersized for this installation, considering the minimum size of 16mm² stated in the table. Maybe upon calculation though this would be acceptable.

Running through some BS7671 test questions at the moment, using table 54.7 my answer is not coming out correct and I cannot see why. Question : Using Table 54.7, select the smallest suitable cross sectional area of 70º C thermoplastic steel wire armouring for a 16 mm² SWA cable given k2 is 51. a) 16 mm² b) 32 mm² c) 36 mm² d) 48 mm² So k1 is 16mm, k2 is 51, so I was using the k1 divided by k2 multiplied by 16. The answer is supposed to be 36mm. ?

Table 54.7 would seem to preclude the use of T&E with undersized CPCs, or is that allowed for by the other more complicated table?

Do you need to have earth from the cu for light circuits? |I have seen several without earth.

Hi john I'm doing my test an inspect course now and the tutor is saying that you still need to bond the cold main even if it's plastic coming into the property then copper after the stop tap. Is this correct?

Hi John, great video that presents the important parts of BS7671 relevant to the topic. I have been poking around a little following a question at college involving the adiabatic equation. I notice you stated the PFC was at the origin which makes sense to me as it is at this point the Zs is at its lowest (i.e. Zs = Ze) which demands the greatest size of CPC (the value calculated at the end of a lighting circuit using Zs for example would be smaller as PFC=Uo / Zs such that the greater the Zs value, the lower the value for PFC and then the calculated size of CPC. I couldn't see anything stating this should be done at the origin however?! OK, here's the problem we have been having. In a question (TNC-S earthing system) which is poorly written in the first instance as no value is given for the Ze (i.e. could be between nearly 0 and 0.35 ohms) we could not get the adiabatic equation to work. Even using 0.35 ohms on a 230v supply returns a PFC of around 800 amps which passes the point of 'instant' disconnection for a type B BS60898 (MCB) 6A circuit breaker (i.e. faster than the tabulated 0.1 seconds (where the thick black line stops on the log graphs in BS7671). This problem would apply to practically all installations on a TNC-S earthing arrangement so using it to calculate the minimum size of CPC required on an old installation doesn't work. I have been told that the equation can only be used where the disconnection time is 0.1 seconds or greater yet the question requires us to prove our value for CPC is proven via calculation using the adiabatic equation! Apparently you are supposed to refer to the manufacturers energy let through data for a specific device in such instances but the project does not allow us to specify a particular manufacturer and even if it did I don't know how we would go about using the equation to prove the CPC is adequate. Using 0.1 seconds invariably returns a value greater than that required for the line conductor and this has got us all pretty stumped. Any advice on how we would go about this would be greatly appreciated. I can see this being a real problem in the future where a board change is requested on an older installation with smaller bonding and main earth bonding conductors and where these are installed in difficult places to change such as under floor boards etc so it would be nice to know how to do this correctly. It is likely that a board change in a residential property would end with and RCD protected board using such type B MCB's for example so making this work with PFC's higher than required for 'instantaneous' disconnection would be very useful?

Hi John, thanks for your great videos. I have a ze reading of 0.13 on a tncs system. 230/0.13 = 1,769. I have a 80a BS 88 -3 fuse. I can’t see on the curve chart the max operating time for this. Please help.

Hi john can you use 16amp mains lead c19 with a 10 amp fuse in the plug

Hi jw quick question The mains is 60 amp fuse The main supply from meter has been run in twin and earth cable 16mm twin and 6mm earth Now I think there is a problem with the bonding because it is coming off of the consumer unit earth bar which is feed by the 16mm twin and earth Should the bonding be at the mains end before the twin and earth on an earth bar feed by a 16mm earth I was always under the impression that 16mm twin and earth was OK for the final circuits but not for the 10mm bonding to then come off of it as well Thanks

Watching this from the Australian Capital Territory. Can others provide comments, url's pointing to relevance links for other nations, besides the UK? Because so much international trade & travel happens now, it'd be good to know the similarities, differences with other nations & products.

John apart from the amazing videos and instructions, you seem to have a great T-shirt collection!

I checked my consumer unit its old and it doesn't seem I have earthing . What can I do to put it right.

Using table 64.7 select the smallest suitable CSA of 70°C thermoplastic steel wire armouring for 16 mm2 SWA cable given k2 is 51. Hi John, would you please explain how to calculate it? Thanks, H

Hi, can you see a reason why a ring circuit should have a 4mm2 CPC, if it still only has 2.5mm2 live conductors? I'm assuming it's to allow the full 32A fault current flow, if the ring is split in any way, there is also no RCD protection on this circuit, as it's a 16th edition compliment installation.

I hope you are doing to do actual classes in the future I will love to attend

hi can you tell me why a metal cooker hood, only has a two core cable an no earth ?

Can you do some tutorials on testing single phase motors and 3 phase motors?

the earthing conductor calculation its same with protective conductor calculation or not ?

Thanks

Could you settle a bet please , what is the main purpose of bonding the water and gas pipe? Is it so everything is at the same potential or is it incase the water or gas pipe goes live if theres a fault and a live conductor touching it, thanks

Going of this why do we use 16mm as standard for earth in most domestic properties, am i missing something

A very informative and thoroughly thought out explaination! I have a question though, why aren't light switches earthed?

Don’t you also apply Cmin while calculating the fault current.

can you please share with us the book that you are using in your vedeo

John I sailed to Norway and I some places plugged into a " normal" 16amp blue three pin L-N & E. Then I occasionally found sockets which were slightly different! Put the meter on then and discovered two lives and an earth. 220 on each live and 110 between lives and earth! So no nuetral?? What would be plugged into that and how would it work ??? Is it a type of PNE?? Surely not

Does anyone know how to certify that their BS 7671 wiring regulations book is the real deal? I rushed and bought one at £45 off amazon because I am shortly to do 17th edition exam which is prob all I will ever use the book for as I am not an electrician. The IET has examples of fake Onsite guide books but no examples of the actual Regulations book

Hi John, Can you soft copy of that book?

I WISH HE WAS COLLEGE LECTURER

The PE can legally be thinner then Phase!? Strange Regulations in the UK...

can you pleas hsare this book in soft form pleas?

Where can you get a copy of BS7671

why is S= sqrt(I^2.t)/k rather than = sqrt(t).I/k which involves one less operation

Can I call you cool John.

Have you been in the military at some stage JW? Your videos are very much no nonsense and to the point.

Superb video John, just one question. Surely it would be an easier calculation if the equation were written: S = I root(t)/k Which gives the same result but it seems pointless squaring the I only to take the root of it a bit later.

very different to usa

Dear John, on this theme of having to run a c.p.c. I had a situation where A timed fan required a perm live/ switched live/ and neutral. there was a twin and earth 1.5mm2 already in place so I have sleeved the 1.mm2 c.p.c. and decided to use it as a sw/L as the fan does not require an earth! it consumes 7 watts total consumption I figure the 1mm2 can carry without problems, I just wonder if this situation warrants deviation from the regs, I was instructed by the client to not tear up the ceiling, if I have done something dangerous How? what should I do, additionally I shall be installing 30mA R.C.D. at the consumer unit, do think mutual inductance/ capacitance will cause nuisance tripping? forgive my spelling errors I am stoned! Good luck john

👍👍👍👍👍

I am baffled as to why leaving out the earth lead of metal-bodied lamps and other electrical/electronic metal bodied devices (including metal chandeliers etc.) is allowed.

When you realise you constantly say 'and uh' you can't stop hearing it

He has his middle finger when he is read the book with his finger

Great stuff. US viewers beware. These are not NEC rules and are both different and have no bearing on anything in the US. Really wrong if you apply this stuff to US.

Should of paid you £4000 to teach me instead.

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are a teacher? u should be !

that doesn't explain earthing from first principles at all, like what problem does earthing actually solve and why is earthing best suited to solve that problem compared to other options.

Too much jargon needs to be cut out for first time learners