Much ado about neutral trippery

Forsooth! A tale of handsome knight and his gnome-hatted gollum riding forth in ye ’olde Ford Transit carriage through fiery autumnal sunshine in Shakespeare’s County toward a perilous RCD trip & rescue of fair maiden from within tall keep of yon castle and... actually, let’s just fix that RCD.
Interesting as it perhaps is to see a backfeed of an RCD via what is presumably diverted neutral current from neighbouring properties. It looks like Jack and Jill Jones up the road have a problem or three with their electrical installation sending current down their earthing/bonding instead of their neutral. Still, it shouldn’t be noticeable to their neighbours Devinder and Deepali Doe; at least, not until they happen to have a neutral to earth fault of their own downstream from an RCD… in which case, they’re fu*ked.
SparkyNinja posted a short showing a large diverted neutral current recently:
• When you isolate the C...
When it comes to currents flowing in and out, Kirchhoff starts having something to say about it all.
For a nod in the next vid, you can buy me and Nigel a festive eggnog here:
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[@andrewcadby]

Good video. Fault finding is the best part of the job for me, I love it. The current measured on the earth conductor may have been normal, and not necessarily the result of a fault on another property. If properties further down the line have a TNC-S earthing arrangement, parallel paths back to the transformer can exist via bonded shared pipework, and, in this case, the TN-S earth. Some current will inevitably make its way back home via this alternate path

[@rossmurdoch7870]

Just watch out for a little steel tab inside some connectors which links to metal casing for earth in some products. Not this one of course, but just be aware that swapping from the Manufacturers order is not always desirable. Great use of the Tester and explanation of lots of various faults and their causes Guys.

[@gregf9160]

A _stunning_ example of forensic fault-finding and diagnosis 😀 Thanks so much for doing this stuff 👍 I love your work.

[@dsesuk]

Cheers as always Greg!

[@jj-hn2ll]

Yep second that

[@bigalz5563]

The kids can watch this tonight instead of I’m a celeb - a proper show!

[@Richardincancale]

First 8 minutes - absolutely nailed the principle of the fault (no spoiler!). Absolutely top notch understanding of what would have left many scratching their heads!

[@dsesuk]

We have to figure this stuff out quickly or we'll never get down the pub Richard.

[@Richardincancale]

@@dsesuk Seemed to work! Did you ever find a job to fill the afternoon or just stay put?!

[@jj-hn2ll]

Lol Top man Richard for your honesty , me too. I tend to self blame myself and continually self flagellate with the mantra I was taking too much time. It somewhat amazes me how the install can deteriorate without a physical movement to the cables but is a nice learning curve to future fault finding. I would be interested what David charged for that lol .

[@Aengus42]

@@jj-hn2ll You've got constant pressure from the clamp pushing on materials that expand & contract at different rates. So there is constant movement it's just very slow. Also, as you know, that a tiny nick in pvc insulation propagates when stressed. We've all done this to remove pvc insulation. Cut a little nick in the pvc & then bend the cable to cause the cut to propagate around. Under the constant pressure from the cable clamp the expansion & contraction due to heat has done exactly this.

[@jj-hn2ll]

@@Aengus42 👍

[@tc6907]

What I love is the fact that no one calls you out on removing the cover on the board while it’s still live and working on it! Which I totally agree with if you are a well trained and competent electrician who knows where they shouldn’t be sticking there fingers It just shows how well respected you are David, another great video

[@dsesuk]

I shouldn't be so complacent. Nige can film my fiery death one day and stick it on here. See how many likes it gets.

[@tamberp]

@@dsesuk That seems more of a Liveleak kinda thing, probably get a lot more hits there!

[@damiandrozdek5688]

@@dsesuk 😂

[@garethlloyd5644]

You two have da skills to pay da bills, another great job chaps

[@pauledwards9493]

Another fine episode of Dads Army Electrical, David.

[@peterrobinson850]

Hi, Dave and Nige, From old an spark from the 60's. Nice bit of fault finding, logical approach but can throw you when you have two faults simultaneously, got totally engrossed again that's real entertainment for an old fart like me. Good call checking the diverted neutral currents you don't want to get part of the return circuit even with the power off, it doesn't even have to be a fault with the neighbours just share return paths. you are 100 times a better spark then I ever was, enjoyed ever minute of these long videos, great stuff keep it up. Peter.

[@dsesuk]

Thanks for tuning in Peter!

[@craigevans9617]

I'll say it again, this is my favourite type of content. Just along for the ride with people using logic to solve a problem. Thanks for sharing 👍

[@AndyNichol]

Best and most informative Sparky on the interwebs

[@dsesuk]

Oh, I dunno. There's that other guy. And that clever fellow. Not to mention the useful chap.

[@davidkelly4841]

@@dsesuk The Boffin ;-)

[@acelectricalsecurity]

Definitely, for all the dicking about, you can tell her knows his stuff, most of the others are interested in product placement, and will not say anything controversial for fear of upsetting the companies that lavish them with goods.

[@stuartandrews4344]

Definitely.

[@GeorgeCox]

(football chant) there's only ooooonnne Daaaavid Saaaavery..... there's only ooooonnne Daaaavid Saaaavery..... (and Nige and Linda!) Great video, guys, and fancy FX with the diagram and all. Love your work. 👍

[@electrician247]

Nice video David. Enjoyed it. Diverted neutral current is something we all need to check for and even monitor while working at main intakes. Something I try to encourage in my small way. The sparky ninja video is from the team at SPEN who released an excellent video in combination with the IET. Sadly the presenter passed away shortly after it was released. Resulting in it currently been unavailable. Great work and as always top banter/fuckery.

[@dsesuk]

Thanks Mark. I must admit, it's not something I've traditionally given great thought to, but an Amp and a half on the ol' green/yellow gets your attention.

[@electrician247]

@@dsesuk Same David. I think that SPEN IET video dropped the day I was changing another CU next to a gas meter and water bond with the main earth flapping around. Gets you thinking that maybe we need to treat that more carefully lol.

[@MS-Patriot2]

What level of voltage is pushing that current ? Is it hazardous or just a PITA to the RCD?

[@dominic_8652]

I love it ‘the manufacturer is a knob head’ 😂

[@petertallowin6406]

I have said it many times before. It is a pleasure to watch your process for fault finding and sticking one to manufacturers knobheadery....... Kudos to Nige for now being marginally less tubby than you. 🤣 Good effort dudes.

[@raymurphy9749]

More of these fault finding vids please Dave and Nigel always interesting to watch with a good outcome. Better than most movies these days 😂

[@NivagSwerdna]

@5:30 1.5A on that earth. Wow indeed. Nice trip around the down light fittings. Thanks for the video.

[@bigwoodrz]

Excellent demonstration of your high level of skills. As said by another, a Masterclass by Dave.

[@stevejagger8602]

High current on the main earth could be a diverted neutral current from a broken/high resistance neutral on a TNC-S connection on the same supply distribution, which is entering the property via metallic water or gas connection via the protective bond. Great piece of faultfinding and long term resolution of the manufacturer/installer cause of failure. Nigel’s comment that the manufacturer is a knobhead is spot on!

[@GeorgeStyles]

Another good episode... Thanks for the diagram showing why it was tripping, made the rest make sense to someone not trained as a sparkie like me. And loved Nigel's hand signals lol

[@JBE]

At least the downlights weren't wired in 2.5mm T&E ! I was on a job recently where such an act had been carried out. Absolute nightmare but that's another story. Nasty fault well found by the dynamic duo yet again. Well done Nigel you deserve that coffee.

[@dsesuk]

Ah, well there's another video showing just such a thing James - it just needs to be sellotaped together! A different dynamic duo was involved on that installation I recall!

[@stuartandrews4344]

A masterclass in fault finding...

[@timhoward7037]

Great video, very refreshing to see someone methodically fault find. These days I carry the prewired Quikwire plug and sockets as they make re-terminating downlights an almost joyful pursuit and I'm sure about 80% of all downlights are recessed cack just waiting to reveal themselves inappropriately to the world. Plenty of ways to skin the proverbial cat but an option would have been putting the quikwire sockets on all the downlights (rather swiftly), IR testing the jolly lot, then put take the downlights to the pub and put the plugs on over a pint. Keep making the videos - love them!

[@BlRaidX]

Tis nice to see a father an son team constantly staying as a team. hahahahahaha

[@stupidmike11]

You really have filled the hole that heartbeat's axing left in our lives, on a Sunday evening 😃

[@dsesuk]

If only I could compete with Countryfile.

[@kevinrichards6506]

I inherited a house full (and I mean FULL) of Enlite downlighters. You are correct, the push fit connectors can be a bit fiddly BUT there's plenty of room between connector & clamp - so even though CPC connections are to one side, the electrician who installed them has kept all the wires well spaced !! I've had to change a couple and it's been straight forward 👍

[@APSuk2]

Sunday saved again!! Cracking video David, great to see some real world fault finding. Loving the diagrams explaining the fault path & how you went about finding where the issue was.

[@sstorholm]

The down lights are probably designed for the European market as our cables are round so the conductor order isn’t that static. Also, our CPCs are jacketed, so the risk of insulation compromise is a lot lower when you need to squash through two layers of primary insulation.

[@dsesuk]

Oh, if only such common sense applied here Sebastian. Unfortunately, I don't think it ever will.

[@mitchnuke]

highly recommend Integral evofire spotlights if you need a class 2 fitting, they managed to keep them fire rating without the "can" on the back of the light so they are nice and shallow if need if depth is an issue. Some CEF and most Toolstation stock them 👍

[@chrisardern4594]

Yet again Dave you deliver a interesting and informative post.

[@taskhunters5245]

Pleasure to watch. You're something else👌

[@martin54123]

Excellent video as always, clear fault finding process. I agree with you that it was better to reroute cables in the fitting to avoid them crossing over, I've done exactly the same myself. I also don't have a problem with the front of the board being off if you are a competant electricain and in control of the environment, sometimes you just can't avoid working on lives sytems, it's the nature of the job.

[@Badgerooni90]

Hearing you both grunt as you stand up 😂😂😂.

[@computeraddic675]

Wel,thats why we have now those small boxes,so you can make your connections between the cables IN the box and then just one cable to the downlights.Its a bit more work,but more reliable because only one cable on the clamp on the downlight.A little knot in the cable IN the box to be sure you cant pull it out off the box.

[@havoctrousers]

came to post the same thing! a 90p chocbox with wagos does the job nicely and it doesn't have to be MF since you can pull it out of the hole to inspect it.

[@alvina69]

Excellent video, I do love me a good fault find video… Some others on here spend ages looking at things and never seem to find the fault and just go around the house tightening connections (not every fault is going to be a loose connection 🤦🤦🤦).

[@TheEmbeddedHobbyist]

When I find what I'm looking for, I always have one more look. That way its never in the last place I looked. Works for me :-)

[@dsesuk]

Genius.

[@johnhales9310]

Winner of the fastest manual screwdriver action 💪🏻

[@pjmurray2927]

Love your videos Mr Salary and Mr Marsh

[@helmanfrow]

2:19 "This is a big old board, innit". I'm always a bit bemused by residential "consumer units" on your side of the pond. They always seem to be about a third of the size and capacity of residential panels in North America. It's also a bit strange that you have to install your own bus bars and that plug-on neutral is only just catching on by you. Also I like your UK Sparky lingo. Y'all talk funny.

[@dsesuk]

We're rather behind the times on this side of the pond. Also, our houses tend to be shoeboxes in comparison to those stateside, and we use higher power circuits for socket outlets meaning there tend to be fewer of them traditionally.

[@helmanfrow]

@@dsesuk On the flipside, UK sparkies (at least those on KZbin) all tend to carry insulation testers which I think are great but which seem to be less popular among North American electricians. We certainly have our fair share of wire faults.

[@dsesuk]

@@helmanfrow IR testers are par for the course here; anyone working in the job would carry one, usually as part of a multifunction tester. They're invaluable for tracking down GFCI trip faults!

[@0liver0verson9]

Ah, some excellent Sunday entertainment!

[@dsesuk]

Excrement Sunday entertainment perhaps!

[@richardburgess6040]

Great video - great explanations, just the right amount of innuendo. That Metrel tester looks good too!

[@andrewberridge4630]

Excellent, methodical troubleshooting. I do a binary chop in similar situations - split at the middle!

[@olly7673]

Another really good video Mr S. I think, judging by the first minute of filming though, you might be wiser giving Nige a length of rope and a tyre to occupy himself rather than the camera. I love to see the way people approach faults, it's very interesting as a viewer, especially when you refer to the tester, showing it in use. I refer to my previous statement! The E5 group showed a clip from Scottish power, I think, on the dangers of having a live earth on an isolated board and made me think should the first part of the isolation procedure be putting a clamp around the earth? I'm keen to see your use of the MI3152 more as I'm looking at it to back up my Megger 1741+ but it's a lot of dosh. Keep up the fault finding vids and your use of the meter please..... just record it yourself :) I don't care what Nigel says about you, I think you're alright.

[@dsesuk]

I need to really set that Metrel to task Olly. So far, it's only been used for some basic faultfinding where continuity and IR are involved!

[@KH-bs2bz]

“That’s our scumbag” 😂 great video lads

[@dsesuk]

@@voltare2amstereo Smart guy, but I'm taller.

[@mbinstallations3484]

KSR firebreak downlights are double insulated class 2, denmans keep stock of them if you need to get some class 2 again I had to get some for the same reason the other day.

[@dsesuk]

Thanks Max. I don't use Denmans much - will have to see if they keep these on the shelf at my local branch.

[@jefftaylor4206]

Dave - Great video, loved the thoroughness

[@djb774]

Safe to say those other down lights on the same circuit will be a similar standard!

[@wilbertbirdner1303]

A service call for another day.

[@hepontour]

Love this stuff...fault finding is my least favorite part of the job..watching these makes it at a bit more fun.

[@AnnoyDroid]

I'm 22 minutes in ( I have watched this before btw ) and I agree with Nigel and yourself Dave, That is wired incorrectly even as a layman the EARTH (cpc my arse) should be in the middle. I think \ know it should be there for one reason safety if either L or N is to work lose then it has a greater chance of tripping the protection and not starting a fire. N.B. I do love you videos and I hope you continue to make more ( and no NB does not refer to a lesser know sparkie on YT )

[@darkdepth1991]

Good video about damaged isolation, keep up the great work !

[@Ragnar8504]

I really don't think these downlights were designed specifically for the UK market and most European countries use round cables, so the location of the CPC doesn't really matter. I'm not even sure if these were designed with building cable in mind, most downlights seem to be intended for 0.75 mm2 flex, preferably one of them.

[@cbcdesign001]

I certainly prefer flex between downlights. Twice as much insulation between CPC and the other two conductors and its just a more suitable type of cable for a fitting that may be moved around from time to time.

[@thedodger1387]

good piece of work . Thoroughly enjoyed the video

[@AdrianColes]

A sunday evening treat indeed!

[@williamlowther7051]

Well done that man, an absolute nightmare of a fault, never came across that kind of fault before on TN-S the DNO needs to sort that out surely, top job

[@steverobinson8170]

Its quite common on older properties where you have one feed split between two or three properties possibly all wired up to different standards over the years especially if other properties don't have rcds , or you have a combination of wiring standards from the DNO where they have done a repair , I.E my neighbours tns my systems tncs because of an earth fault both run from the same feed cable in the street , my boards latest edition her house was rewired about 50 to 60 years ago

[@Arachnoid_of_the_underverse]

All thats need is the burning fuse across the screen and the mission impossible music in the background, oh and the glamorous assistant ( maybe you can get Nigel to wear a tutu as part of his PPE).

[@matthewbeddow3278]

Great video chaps, making the world a safer place a little bit at a time.

[@jimginn7163]

Nice job you two👍😁

[@notoriousspf4813]

Absolutely superb video.

[@johncooper5293]

Fine bit of fault finding. Both have an eggnog on me.

[@mastergx1]

I know your not a fan of the LAP brand but I've been using the LAP AIO downlights for about 4-5 years now and haven't had a single failure (thats many hundreds of units - they seem to be far more reliable than their retrofit counterparts). They are Class 2 and very compact, easy to install units. I actually use 2-core flex on the first fix as its dead easy to terminate in these fittings. Give them a try!

[@frankmcalinden3699]

Another great video !!! keep up the great work chaps!!

[@brizy231977]

That has to be Deta downlights, their smoke alarms etc are the same, the neutral and the interlink terminal are the wrong way round for 3 core cable.

[@tompickford2697]

Love your videos big Dave !!

[@dsesuk]

Well shit Tom, I love you too.

[@peterrobinson850]

Hi Dave, it’s me again old spark from the 60’s. I’ve been doing some mental exercises with the faults you encountered with RCD tripping, I would love your opinion on these scenarios I’ve been pondering over for a few days now: (1) why was there two simultaneous faults ie 1.05 ohm leak between E-N and IR failure, one of these faults should have shown up first, (2) you demonstrated that the diverted earth currents caused the RCD to trip with no power on, so my conclusion is there may have been some form of surge breaking down the compromised crushed insulation at the light fitting causing the two fault to appear at the same time if so it could mean so form of failure in the supply that may give rise a more dangerous situation in the near future, it seems strange two fault at the same time and both would on there own cause the RCD to trip, I may have finally flipped and ready for to be consigned to the loony bin. Peter.

[@kobirelf97]

Funny thing is talking about having the CPC not in the right position I've recently wired a ring floodlight camera and the CPC was in the wrong position In that as well

[@matthewmelbourne9139]

Fantastic video, and demonstrates the methodical approach to fault finding. At what point should high currents on the main Earth be investigated further? Is it resolvable, as it could be a cumulative effect from multiple adjacent properties.

[@YouzY666]

Probably the heat from the radiant accelerated the insulation failing under the mechanical pressure

[@FrontSideBus]

An amp and a half leaking into the earth would cost a bit of money over the course of a year! I quite like those Ovia downlights that have those "click" connectors on them. You can wire them up without having to support a big downlight which is flapping about in the breeze and then just plug them all in at the end.

[@boggothedoggo3890]

Had this the other day on a job , silly amps on the water Pipe ,told them I would come back when they had a fitted a insulating section as it was dangerous to even work on

[@sdgelectronics]

On split load boards, MCBs per RCD doesn't really mean much though. You could divide an installation into one MCB per point if you wanted to or into just a couple of circuits for the whole house... They're not ideal, but it's rare people get nuisance tripping from regular appliances. Enlite Spryte downlights are fairly decent Class II downlights btw, seem to last well. Not fire rated however, but often not required anyway unless that ceiling forms a fire compartment. Is that Metrel battery always flat though?

[@davidb3537]

Hi, Not keen on what I presume was only basic insulation being exposed on the downlight manufacturers cables , why bother to ensure the cable sheath is in the cord grip if the manufacturer doesn't double insulate their cable??

[@alexdougherty4905]

I have always wondered about that in those fittings🤔

[@maxbayliss5184]

It should be "reinforced insulation" which means they can do that as its not as week as just basic insulation.

[@alexdougherty4905]

@@maxbayliss5184 👍

[@dsesuk]

I contacted Premspec a few years ago about this (I think it may have been via Twitter) and they said the wires were in fact double-insulated.

[@alexdougherty4905]

@@dsesuk i want to get hold of one of them fittings and chop lumps out of it now!

[@peterc3228]

Good engineering call on reconfiguring the wiring layout to suit t&e cable 👍

[@acelectricalsecurity]

There's nothing more annoying than finding twisted conductors in a single piece of green/yellow sleeving, but if you like to twist the conductors together, sleeve them separately and just twist the ends together, that's what I do, and it's easy for the person following to split them, if necessary.

[@arniewheeler4673]

agree 12:15, adjusted myself for that very reason

[@tomgriffin286]

I enjoy your fault finding videos. I thought it was the convention to run the CPC/earth in the centre on the connection block. It must have been a builders job.

[@johnburns4017]

It was labelled by the maker that way.

[@johnburns4017]

This rogue current coming in via the earth from an adjacent property will run right though the earthing system in the house. If there is a metal framed appliance that is earthed, this may cause problems when touching it.

[@havoctrousers]

Depends on the voltage. If it's over 50VAC then I'd worry.

[@CallumWK]

New logo looks nice

[@dsesuk]

Thanks Callum. I like the 'up yours' boldness the new capital letters suggest.

[@CallumWK]

@@dsesuk See if you can hide a 1 finger salute in there somewhere

[@martinoneill7005]

Great video as always 👍

[@MS-Patriot2]

Premspec - sounds like some kind of delay cream for the over eager, when Nige tries to “pull it off” or to prolong the action during the marvellous segue way at 37 min 47 sec.

[@tsheritageengineering]

Had a nuisance tripping on a lighting circuit happening first thing in a morning, reset and all ok for the rest of the day. Of course it was the last fitting in the circuit! Turned out to be a choke in a fluorescent fitting breaking down.

[@masondoxey6570]

What screwdriver (blue one) is that?

[@richard-riku]

20:54 this problem with the order of the conductors is something the UK is stuck with thanks to the funny flat cables you use .. and the CPC does not even have its own insulation!! in Europe our cables are round and all three conductors insulated. Should the light manufacturer order their connections specifically for the UK market?

[@Webbster77]

Savski.. when you measured 1.05 for the resistive fault would you be expecting a higher number? But because there was a fault the number was lower? I don’t fully understand what’s happening.. your dedicated viewer.. x

[@Webbster77]

And how do you know the current on the earth isn’t leaving rather than arriving?

[@Webbster77]

Ahhhh you did an IR - I thought you did continuity when you said low ohms! 🤷🏻‍♂️ - watching it now like

[@Webbster77]

Wait a sec… maybe not IR… I’m near the end and you specifically said IR. Gonna have to watch again

[@dsesuk]

Webbster! Between live cores (LN) and earth, I would always expect a high resistance. An infinite resistance ideally, but there's no such thing as a perfect insulator. Still, a basic Ohmmeter test should be off scale for the instrument (>1999 Ohms in this case). Going beyond a basic Ohmmeter, the IR tester tries to push an EMF into the wiring (250V or 500V usually) which pressure tests the stuff. If the insulation is weak, some of the Voltage being pushed in will leak back and the tester can calculate how big the leak is by what it receives. Ideally, 0V appears on the return probe and the tester shows off-scale high (999M Ohm). Here, we got 1.05 Ohm between neutral and earth which is pathetically low. So low, the Ohmmeter function can pick it up by squirting in just a handful of Volts. No point progressing to an IR test with that kind of reading as you have a resistive short. Nothing should read just a few Ohms between the live bits and the earthed bits, and an RCD will never click on with that kind of fault so it has to be found. Nigel seemed to remove the resistive fault when he took out the first downlight as N-E started reading >1999 Ohms again, so we went back to pressure testing with IR, but we were still getting a low number. Later, we seemed to get a resistive fault again which I can only put down to us either misdiagnosing where we were picking it up in the first place, or that our pulling out the downlights disturbed other poor connections and varied the test results. Both the short between N-E and the low IR were resolved by our re-terminating all downlights. Does that help, or muddy the waters more?!

[@Webbster77]

@@dsesuk no that’s mint me owd! Thanks for taking the time to reply like!

[@andrewberridge4630]

I'm surprised at just how many buttons you need to push on the Metrel to do the IR test. Much prefer my old Megger where you set the mode, then it's just one press!

[@acespark1]

Spot on as usual David

[@djb774]

Liking that meter!

[@fairplaytoyou2041]

how is the metrel doing and would you buy it ! or is the extras not worth the kings ransom

[@croikeymatesthrowashrimpon8130]

could the downlights not be designed to have a flex?, the old way of jb - flex - light

[@dsesuk]

Absolutely. But why as an installer should I have to source and charge for additional components to connect these things to the basic wiring poking out of every ceiling? That's a case of the manufacturer leaving it as my problem instead of ensuring the solution is built into their product.

[@croikeymatesthrowashrimpon8130]

@@dsesuk 100% agree, poor design on their part which essentially lead to this fault finding adventure. i really dont mind doing new downlights with the maintenance free connections, theyre actually much quicker to do, did 37 in about 2 hours the other day, whilst the units themselves may cost more, the time saved on flexing and junction boxing the cheaper brands of downlights is a labour cost saving for the customer in the end. i dont miss my first year flexing up those old lights lol. anyways, heard your name on another channel and thought id give you a watch, more my cup of tea without the pretend pleasantries of similar channels lol

[@adcuz]

Are these fittings deemed as OK, with the single insulated wires coming from the connector box to the body of the light?

[@dsesuk]

I called the manufacturer out on that back in 2017 when I first came across the brand and they told me they were in fact double insulated. The outer jacket is presumably just colour coded making it look single insulated.

[@skamuk1]

Dave I’m struggling to understand the ‘neighbouring current down the earth’, and maybe I’m being naive but I thought that the current will pass through the path of least resistance, does this mean the neighbours don’t have a good main earth? As I’d expect fuck all on my meter from them if they did have..

[@skamuk1]

Little observation, because I’m a sad bastard, but surely those downlights with their single insulated cables don’t comply from the start?

[@JohnoLapse]

Current doesn't all pass through the path of least resistance. It does do that. But it does it in inverse proportions. So a bit will go through harder to get through cable relative to how hard it is to get through. Effix did a video on current and ring mains which should explain this a little bit better

[@pault4793]

Hi David , just wanted your opinion on the metrel 3152 , as just having my kit nicked i was thinking about this , i had the 1741 meggar , appreciate your thoughts thanks

[@dsesuk]

Pricey but well featured is as much as I can say at this point Paul. Although we've had it a few weeks, this and the last fault finding video are all we've used it on, and that's not exactly putting it through its paces! I need to find time to sit down with it and go through the full feature spec. One concern I've heard from others is on battery life, but I can't answer to that as of yet.

[@pault4793]

@@dsesuk thanks

[@CivilisedMuffin]

If you disconnected the resistive fault why was there still 1.7A on the main earth? Doesn’t that suggest another neutral fault at the property? (Not a spark so maybe I’m wrong for reasons I don’t understand and would be glad to be educated).

[@dsesuk]

The current on the earth was external to the property and was present with all circuits off at this house. It could be coming from next door, it could be from ten doors down. It could be a combination of currents leaking from multiple installations. It was never noticed before because it wasn't causing any ill effects, but once you get a neutral-earth leak on an RCD protected circuit, that rogue current has a path to cause mischief. If there had been no RCD here, the lights would have stayed on and even more current would be leaking out.

[@samd2660]

My understanding is that the earth current here is caused because of an issue at a neighbours property, which means current is travelling from the neighbour, through the earth and piping etc and through this properties earth (some current is normal in all tn-s/tn-cs systems because the electrical earth _can_ be a fair distance away from the property), the issue was this current was actually travelling through the neutral because of the fault. Since neutral and earth are effectively the same, it triggered the RCD because it had the current from the neighbour coming back, that wasn't being supplied by that installation causing an imbalance. Hope that helps, and I stand to be corrected as I'm also not an electrician.

[@CivilisedMuffin]

Ah thanks, it was the parallel path to eg pipes that I hadn’t considered.

[@busman2000]

Would that same fault have presented it'self in an M.E.N earthing arrangement? As that's what we have here in N.Z.

[@wilbertbirdner1303]

The N-E resistive short? Yes. But the RCD wouldn't likely trip with the circuit off like it did in this case, as the current path would be through the lights to the neutral to earth.

[@goodplacereviewer2495]

How come when you flicked the rcd up it didn't trip the other rcd because I would of thought the fault would have ran down that neutral and then through the other rcd's neutral 🤔

[@dsesuk]

The other RCD is connected in parallel to this one, but the current won't backflow through that because there's no path through it to get to earth. Well, not unless there's another fault to earth on one of the downstream circuits that RCD serves.

[@jamesfollon]

excellent video !!!

[@allanmould2633]

Another good video david

[@steverpcb]

If the LNE markings are proud they can be scraped / sliced off with a stanley, if recessed they can be scraped untill iledgible.

[@dsesuk]

I could also re-label them using my Brother label printer, but if someone in the future is intending to make any alterations to those things, you'd hope they'd go by the wiring colour over anything else. If they get too confused, you'd have to question what they're doing dicking with the electrics anyway!

[@steverpcb]

@@dsesuk You raised to posssible issues yourself, I prefer to use an idiot proof system even though there are no system proof idiots :( Worst case that I can think off is a comercial building 30 years ago, TNC, SWA running across a football pitch ( route unknown probably the long way around ), everything in the building connected back to the Switch Fuse where all CPC's were connected to each other but not to the body of the Switch Fuse that the SWA supply used via gland, everything was spiders legs in mid air ROTF This is the same building that I have mentioned before with the 10mm TWE traced back accross the loft to 4mm twisted with a flag of tape on the twisted in air conductors !

[@haldo691]

No matter how idiot proof you make something there's always a bigger idiot to prove you wrong

[@helmanfrow]

Why not swap the choc block out for Wago 224s? Even 221-413s. I don't know about you but I'm in my mid 40s and the less time I spend on a ladder fiddling with screwdrivers with my arms overhead the better my day is.

[@nedloh17]

17:06 Should that cieling fitting have had a brown line wire as opposed to the red one

[@dsesuk]

I think they were brown Dave, it's just the poor light and the potato camera we used making it look a little off-colour!

[@Ragnar8504]

@@dsesuk Many countries don't prescribe a specific colour for the line anyway, more along the lines of "any colour but green, yellow, green/yellow or blue". Cable and flex manufacturing standards do require brown, black, grey but where singles are used you won't necessarily see those colours. France and Romania are quite fond of red lines whenever using singles. Manufacturing standards for appliances and light fittings are another whole new can of worms, I've seen all sorts of colours there.

[@geraldelwood9660]

I confess that I am perplexed as to why after fixing the fault at the first light, and the IR was 999 at the switch (which presumable supplied power to all the down lights), there were still existing faults at other down lights. When the fault was still apparent at the CU, I thought the fault must be between the switch and the CU. Back to the drawing board for me 🙂 The lights look super cheap - Electrician takes the trouble to enclose single insulation within the terminal block cover, but the manufacturer has single insulated wires flapping around between the terminal block and the can.

[@dsesuk]

We may have ballsed up with our testing on the day or our disturbing downlights perhaps opened new problems. It's hard to say after the fact. But, that's faultfinding - it's not always completely clear cut. As for the downlights, Premspec told me their wires are double insulated and are just coloured to look like the basic insulation.