EARTH LEAKAGE CURRENT - WHERE it comes from and HOW to measure it. - MEGGER DCM305E
Exploring intentional earth leakage current and how it can affect the design and operation of your electrical installation.
What are the recommendations in BS7671?
How does it impact your choice of consumer unit and circuit protection?
What is the easiest and most accurate way to measure earth leakage current?
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Megger earth leakage clamp meter DCM305E
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== VIDEO SECTIONS ====================
00:00 Earth leakage currents using a Megger DCM305E
00:25 Unintentional earth leakage currents (accidents & damage)
01:10 Intentional earth leakage current ( EMI filters)
02:20 IT equipment earth leakage
03:00 Sub-division of circuits to minimise earth leakage
03:49 Consumer unit selection
04:30 Measuring earth leakage current
05:50 Parallel earth paths
06:40 Tracing the origin of earth leakage currents
10:00 Checking earth leakage before a consumer change.
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❌ This content on this channel is for electrical professionals.❌ ==================================
📹 Presented by
Joe Robinson - Technical Editor -eFIXX
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#efixx #megger #electricians
I absolutely love your videos. Your explanation of these electrical topics are second to none. Thank you.
Thanks for the feedback David - if you want any specific topics looking in to just drop us a message 👍
@@efixx maybe explaining what needs to be considered when a CU is a long way from the incomer or sub main stuff?
I use a megger Dcm300 all the time. I use it mainly when looking for diverted neutral currents at the MET when carrying out an annual inspection on a petrol station. Diverted neutral currents can leak from neighbouring properties and through existing TNCS systems on to the petrol filling station and then leak to ground through buried steelwork and pipework in explosive areas such as petrol manholes and tanks. It is now common practice to use TT on all new build petrol stations because of this risk.
Over 30 years ago, I used to calibrate all kinds of equipment as a job. Including clamp meters of course. One thing to call out for both analogue and digital meters is that their most accurate readings are quoted at FSD. ( I.e. full scale deflection- an old term used when looking at the indicator needle on a analogue meter) but due to non linear characteristics of components such as hysteresis loss and other items I will not go into here, it also applies to meters with digital displays. . So if you have a clamp meter and you are using the 200 A range, then it’s manufacturer might quote an accuracy of 1% when measuring 200 A, hence readings around 195 A will be almost as accurate. However, measuring instruments are non linear. Hence if you are measuring a load of 1 amp on the 200 A range, you may have a significant inaccuracy , maybe a 20%-30% error! Or more on an analogue device. E.g. old fashioned AVO 7 meters could be more inaccurate for measurements near the bottom of the scale. So my advice is :- when buying a testing device ( of whatever price range) ensure you get one which has a low milliamp range. This ensures that when measuring leakage current of only a few milliamperes, you are operating as close as possible to the top of the meters range to get best accuracy. If it’s an auto ranging meter, then manually over ride this to select the appropriate range.
Most digital meters accuracy is stated as percentage of reading +/_ anumber of digits.
Being in my 60s FSD is a term I was brought up on. I've always had the same mentality towards what you rightly say. In fact it's so embedded in me that if I'm cooking something, I often add the ingredients straight into the pan which can weigh say around a kilo. If I place that on the scales, zero it and then add say 100 grams of something, I instinctively think that won't be as accurate a measurement as if I'd weighed it in something much lighter. A slightly different analogy but an indication of how you think about things when you're brought up in with this kind of thing.
Very well put. I actually find automatic raging can be irritating for the reason you referred to.
Great video as usual Joe. I was trying to explain this to someone the other day and getting nowhere 😕. I sent them this and we both watched it at the same time. Now not only does he understand what I was saying but he's heard it from someone who knows exactly how to explain things and with much better language than I can hope to grasp. Thank you.
That's surprising... because usually Dave Savery is pretty good with this stuff ! Maybe it was too long after 'beer-o-clock' ?
Great comment as usual J Beck
Wow, just stumbled across this comment, must have missed it the first time round. Thanks James, that's really kind of you to say, makes me happy to know it's helping people. 😊
Your way of explaining what is happening is very educational. Great video and very informative
Good Video, clear and concise without any ego, refreshing.
Great video. This is something no one seems to talk about and also explains how the leakage is measured between live and neutral. I worked for a company that had a vehicle EMC chamber and it had a massive filter on the outside that had a high leakage current. Until the time it was installed I had no idea of permitted leakage currents in the regulations. Also, if my memory serves me correctly it had to be wired back to the fuse board in SWA cable. That was around 15 years ago so my memory might be playing tricks on me. We also couldn't power any equipment with RCD sockets because of the noise they generated.
EMC is a very specialist area you could be right on the RCDs is they where on the chamber side of the filter.
brilliant ! I have loads of earth leaks at work at the moment and someone briefly mention to me about this device but was not to sure about it until i see this explanation.
Great video again 👍 I don't use my EL Clamp meter alot as we don't undertake alot of fault finding but when I have needed it, what a bit of kit. An essential bit of kit for certain scenarios, will always carry one on the van .
Agreed!
Superb content very well demonstrated. I have owned and used clamp meters for many years as an electrical technician, I usually buy high quality meters that can accurately measure both AC & DC currents because I work on DC circuits in CBU's and vehicles, which makes life easier when looking for parasitical drains and figuring out expected autonomy times etc. If you are in the fault finding game you should have a clamp meter in your arsenal guys.
Thanks Joe, a very easy to understand video presentation-
My pleasure, thanks for commenting!
i have learnt so much from your videos-50yo sparkie.everydays a school day
Iv'e had an Amecal low current clamp meter for about 4 years, very usefull for tracing earth leakage ... mainly washing machines, ovens, and water heaters i find faults on. great video.
Exactly - not IT equipment. The "No more than nine IT devices on a ring" is an old-wives tale in a modern house. If you have a mainframe, then we can talk about ELC. Cookers are some of the worst. Especially when some jobbing sparky has attached the live and neutral backwards because "Hey. It's AC so it does not matter." - I hear this comment from too many sparkys!
Excellent, this is why we limit circuits per RCD here in OZ, no more than 3 and no ring mains, pros and cons for each, but that was very informative, and i will be showing my students, thanks mate
Excellent bit of kit Gordon from megger showed me all its usages
Ah, we love Gordon From-Megger and his brother Lee From-Megger!
Great video, easy to understand and very useful.👍
Great Video Joe , you can also use the meter for testing single and three phase appliances, especially equipment incorporating a no volt coil motor starter ( A contactor/relay that can only connect the load to the circuit when energized or typically a floor grinder etc ) , that way without dismantling the appliance the actual running leakage current can be measured via its supply lead with an adapter. Unsure of your standards in the UK but it may be in the order of a max 1mA for double insulated equipment and 5mA for Class one earthed metal appliances
Got one, thanks for the reminder. In fact, I may use it as first thing before doing anything else for EICRs. Great for RCD fault finding!
It is isn't it? 👍
I’ve had my dcm305e for a little while and it’s already paid for itself in the time saved fault finding nuisance tripping. I would highly recommend buying one
Ideal for EICRs in stately homes 🏠 😂
I lost mine 🤦♂️
I started using an earth leakage meter a few years ago. I can’t quantify the stress it’s saved me before doing a consumer unit change. If the earth leakage reading is off the scale I don’t even bother quoting for the job. I just explain to the customer that you’ve a pre-existing problem. Not worth the grief or risk of tripping after changing the unit. Well worth the money.
Great to know thanks for commenting. 👍
Do you isolate the problem then give a quote?
@@johnburns4017 I used to but I’ve formed the opinion that it’s not worth the risk of nuisance tripping coming back on you. Once that starts then you’ve inherited the problem. Got to ask yourself, do you really want that? IMO life’s too short for that and after 31 years of being an electrician I’m aware of the stress that something like that can bring.
Anytime anybody wants a board changed if its not had a rewire I wouldn't even entertain it .
Paul Hayles So you find an easier way to make money and leave someone with a future electrical fault ? Brilliant well done
Great video, really well explained. I'm an electrician in Spain and I've been using a leakage current clamp for about 6 months now and it's been great help. However sometimes you get an RCD tripping due to transient impulses, high frequencies or presence of loads. Then you have to install a "super-immunized" RCD. Not sure if they're allowed under UK electrical code or not.
Hey, I'm in Spain too and I came across this video because my RCD is tripping randomly. How would I know if the RCD I have is super immunized or not? EDIT: Nevermind, I found the symbol. It looks like mine aren't so I will replace them.
How do you mean super immunised?
A lot of vids out there but you actually using the metre at the board just gets it to click a little easier for me anyways, 👍 so thanks for posting
Our pleasure, thanks for watching and commenting. 😊
Very interesting video. I recently discovered how valuable this technique can be as a quick and easy way of checking whether an old installation will stand up to a new fuseboard. Had a client recently that had been told they should get a full rewire from a previous electrician despite his own IR readings on the EICR all being healthy passes. A quick clamp meter check showed a 3ma leakage on the whole installation. New RCBO board fitted and everything works fine.
So you charged a client for the installation of a brand new CU when a total of just 3mA leakage overall was/is peanuts! What did you do to isolate said current imbalance to a specific circuit, then to a specific device? Sounds to me that you, like the previous sparkie were conning the customer. Please explain what EXACTLY in the old CU was faulty such that replacing it removed the fault completely? What devices were left off and/or disconnected on the second overall test? How do you KNOW for certain that you actually cured the "fault" given that it is HIGHLY unusual in today's electronic device saturated environment that ANY modern household would have ABSOLUTELY ZERO current imbalance? ESPECIALLY with so many SMPSUs around, ALL of which have designed-in SAFETY leakage paths to earth/ground. Sounds more like a self satisfied smug response, with no detail of proof of problem! 🤔🙄👎
@@boblewis5558Perhaps I didn't explain myself fully, although you still decided to jump in and judge me... So from the beginning again, please pay attention... The client requested a new consumer unit as she had recently moved in to the property and wanted things to be brought up to date. Her current board was very old, house split across two boards containing rewireable fuses. Sorry, I did not make it clear that she had requested that in the first place. The bit I did explain was that the previous electrician that had done a 'satisfactory' EICR has suggested she 'needed' a FULL rewire. After doing the simple test and finding a negligible earth leakage of 3ma. I told her that I didn't think it needed a FULL rewire and that the new board would not experience any nuisance tripping. So I DID NOT con the client! I could have agreed with the advice of the previous electrician and gone with a full rewire. But, despite the opportunity of a big job I was honest with the client. The board was fitted and all fine - no tripping of any circuits. 3ma leakage across the whole house is quite acceptable and does not indicate any faults to rectify. Perhaps, you may have given a different comment if I had added the fact that she had requested the consumer unit in the upgrade but by the judgemental tone of your comment I doubt you would...
@@chrisknowles2578Ah! A VITAL piece of information which I didn't have as you rightly say. In which case I apologise unreservedly for impuning your integrity. The customer is always right, and you cannot argue with some at all. 🙄 You are incorrect that I would have not changed my comment though as I wouldn't have written it at all. Hopefully my apology is sufficient to demonstrate that.
@@boblewis5558 Thankyou for the apology, it is appreciated. The story did not end there though... After quoting for a new fuseboard and suggesting that a full rewire wasn't particularly necessary... She said she would like me to go ahead with a full rewire anyway!! I gave her a reasonable price and she was happy for me to proceed. All complete. She is very happy that although it was not essential she now has the peace of mind that all the cables and fixtures are brand new and safe. I was happy to get the work and feel I have a clear conciounce that I had not pushed her into having the work done.
That was very useful information. i use the Metrel MD 9272 leakage clamp, i have found several problems with it. An earth leakage clamp is as important as a multimeter in the kit, especially since the tripping is a type of load dependant trip it can be difficult to trace.
Thanks for these informative videos- very useful. Please note that when reading in milliamps as in this case, you were reading 20 thousandths of an amp, not millionths. Milli is 10^-3.
I think it dropped 0.6mA when you disconnected the Laptop, but all in all a great clear demo Thanks Joe
Had one for years and yes they work very well for us
Good to know! 😊
Nice idea. Normally take insulation readings but this is quick and easy will get one.thanks
Doing insulation reading exposes a risk these days of blowing electronics. To find this nuisance tripping, you need the electronic equipment connected.
Makes all the difference mate Like having a crystal ball The megga kit is fantastic. Great video mate I can see you training the newbs in the future 👍
Thanks for. Video For sure. I'm. Gonna need one Very helpful to have
Thanks - your vids I've recently watch have given me a new problem - supplying a house with no RCD via a genset with RCD - could be a problem when all the lights go off in the street !
Great guidance and insight.
An accessory to build is a 13A plugtop to 13A socket with separate L N and E wires between. Then suspect or items that require to be proven good or bad can be tested individually and tested independently.
i must do this. Thanks for the tip Bob
Can you elaborate please 🙈🙈😂
@@pooley2853basically, just a normal, but very short, around half a metre, extension lead but with the wires exposed so they can be accessed individually.
Great video very clear explanations
Thanks very much! 😊
Very helpful video. Thanks 👌🏻
Very informative viedo! Better to test with all appliances with load!? There is a chance we may miss the faulty appliances with this leakage testing
Awesome video mate
Would it not be easier to leave clamp meter round main tails and just switch each circuit breaker one at a time
Thanks. I was wondering how you would ever use one on a board wired like a rat's maze or with little cable give
Easier yes but that would kill power to the house which might be inconvenient.
@@mfx1 calls an electrician for a fault, doesn't want any inconvenience.
@@TheFool2cool That is prpbably just meant to explain that this way, in this case, with this amount of slack on the wires and with this amount of space in the cabinet, you can do it without turning off any circuit breaker. (That might be inconvinient or unwanted in other situations) So in my opinion Martin King made an excellent remark
Interesting, thanks for that information
Thanks for the info, very interesting.
You're welcome! 😊
Great video!
Thanks very much. 😊
Very Good vidéo . Thank you for sharing
Thank you Very helpful
Yes I have had a earth leakage clamp meter for several years and found it is very helpfull. Would recommend getting one . I wonder if anyone has come across a chart which indicates the health of a circuit by the recorded earth leakage values.
Interesting idea. 🤔
Nice to see such well organised distribution bords. 70% of distribution boards what i meet on site are NH or E27 fuses from 1980's. Wiring there looks like a spaghetti.
Electromagnetic Compatibility (EMC) or Conduction, but more usually EMC is using the word Conduction not 'Contamination'.
It's also possible to calculate the insulation resistance for an item whilst it's powered up, very useful for items that are sensitive to high voltages used in insulation testers. We use it on fuel dispensers and sewage pumps whilst they are powered up.
I use the T.I.S earth leakage clamp meter, worth every penny. Every tool bag should have one for EICR'S or board changes. Great video mate.👌
Why EICR because you would to an insulation resistance test anyway.
It's just another tool in the armoury to find problems. Could potentially spot an issue before you even turn the power off. 👍
Thanks very much. 😊
Same one here one of those tools that when you need it it's a god send
Great vid mate thanks
Why not take the reading in amps a then convert that to mili amps ? Fantastic video very interesting. Nicely explained Joe.👍👍❤️⚡️
excellent info, thank you
Our pleasure!
Thanks. Good video👏👏👍
A simple ramp test can give a perfectly good indication of leakage also. This for me would only be useful for consumer unit swaps where there is no existing rcd protection.
Not really. That’s just the RCD you will be testing not the load that’s causing the problems
Good video,I’ve had a low ma clamp for a year now,no way could I do without it,got a cheapish sparky brand tester which does the job.
A tool box essential 👍
Excellent!👍☘️
Pretty essential on both electrical power showers and immersion heaters. I had VERY bad leakage from our immersion heater which did NOT trip the RCD but using the back of my hand on the shower wall, the shower fittings and the aluminium frame of the shower door, I could feel the tingle of mains!! Isolated the immersion heater ... Problem gone. Turned out the element was VERY badly corroded and I suspect that water had entered and gone through the porous ceramic insulation on the heating coil!! Didn't have a clamp meter at the time but I do now.
Woah! Scary stuff! Good find Bob.👍
Very much doubt you felt the tingle of the mains, possibly the pressure of the water running through the pipe if anything. Best way to fault find is testing for insulation resistance using the megger
@@marlonwaites3718 the tingle WAS mains! I proved it beyond doubt. Can't feel water running with no water running! Duh!
Are you saying you felt the earth leakage through the wall?? 😂
@@marlonwaites3718 not "through" but "off" the wall! Granted, only near the shower head pipework & thermostat. ONLY there was nothing when the immersion was isolated. Shower was power shower NOT electric so not from the shower and not from the pump ... Impossible from the latter due to plastic fittings and impeller housing. It shouldn't be that surprising, lightning voltage gradient is effectively spherical in its scope, passing through anything remotely conductive ... i.e. brickwork and tiles. So mains can do the exact same thing. In addition i checked the copper hot tank and its surface was live! Tested with an old school neon screwdriver! Tank bonding was renewed too afterwards ... May have been the main problem I guess since the RCD didn't trip.
Great vid very clear
Thanks for saying so. 😊
Efixx doing a great job trying the get new innovations in front of UK electricians. However take up of these is incredibly slow in the UK, partly it’s cost driven but let’s hope manufacturers also realize the potential for better pricing to get into the market as a first mover.
Thanks, we're doing what we can! 😊
@Math Man Quality reliable tools are not cheap, but sometimes the're worth their weight in gold.
Interesting video. Looks easy when checking RCBO's as the Line and Neutral are close together. I would be interested to see how an old fuseboard is tested. I see a comment suggesting clamping the tails and turning on/off circuits, would this be a better way to check old fuseboards before installing a replacement?? Thanks
Literally what I was thinking
Extend the neutral conductors from each circuit within the fuseboard creating a loop and reconnect. long winded but correct reading can be taken between L/N. Or, find the L/N elsewhere on the circuit but you have probably worked it out by now as I'm 2 years in the future.
Is the intentional leaking related to the little shocks that we get touching some home electronics?
I use mine when repairing boilers, ideal when pinpointing ' un intentional' earth leakage causing nuisance tripping.
Brian Cox of the electrical world!
Yes I have one here in France, not a Megger unfortunately, a cheap Chinese thing. Nevertheless it's really helped me in fault finding nuisance tripping and confirming that my install is below the maximum permitted leakage for any given RCD (which in France is 50% of rated trip current, unbelievably. I've never seen a figure anywhere near that on healthy circuits!)
thanks very much for your video, very instructive , but i want to know the price of an earth leakage clamp meter and where to get because i am in Ghana and i use to follow your visit
I got one from a different make cause the clamps is like an oval shape so in tight places where they is lot of cables its bit easier but. great machine thanks for the video
Thanks for commenting! 😊
Could this theoretically replace an insulation resistance test between Live conductors and earth?
When I first started retraining as a electrician the sparky I was assigned to told me to buy a clamp metre I soon found out why 👍
Probably going to become even more important as time goes on. 👍
Many clamp meters are integrated into multi meters (have not seen earth leakage clamps in multimeters yet, maybe someone can inform us). Screwfix sell a decent LAP version for around £30. I used one of these, with it being quite good. The problem with the cheaper products with some of them, is not with the instrument, but cheap leads. Buy quality leads and use them, then they seem OK. But the initial cheap attractive price is then hyped.
Difference between a clamp meter and an earth leakage tester though, a lot more sensitivity, I’m training as an EST, got asked to follow an electrician regarding a tripping RCD, my fluke 902 lacks the sensitivity to see if the tripping is due to the earth leakage, all I can say is the appliance will run without the house plugged in, but plugging in the house alone will be fine too.. they just can’t be on together… they either get hot water, or lights…the house is like a permanent caravan, connected via a caravan plug to the RCD within the main house…
@@f1reguy587 the house plugged in? uh?
Briallint video, thanks Joe
Our pleasure!
Great video but can you also tell me if such a clamp meter can be used on a mains lead eg a toaster or other appliance to check by appliance what is generating high earth leaks?
Very nice bit of kit, If i were still on the tools: i would be ordering one tomorrow. Thanks Joe.
Thank you Brian!
Hi Joe, from an old spark from the 60's. I think all your video's are extremely informative and well presented I really enjoy them immensely. I would just like to ask you a question, I own 3 earth leakage clamp meters, I like to do regular global tail checks to ascertain whether any early signs of problems in mine and families homes, I would just like to know what you would be consider unacceptably high main earth current probably emanating from the neighbours or street light leakage, I also do all my own bumbling and always use a bonding lead before I disconnect any joints just in case it's carrying return currents, be interesting to what you consider too high main earth current before investigation further. Peter.
Hi Peter, great question. This is a really interesting and deep subject which is a bit tricky for a comment here. Please stay tuned for future content on this matter. Thanks for commenting. 👍
@@efixx Thank you for the feed back, I look forward to your future video's. It is a very interesting subject, and I think high mains earth currents will escalate with the with the massive demands for EV charging resulting possible more neutral faults in TNCS systems, something the power demands was never envisaged when installed years ago. Peter.
Should it become standard for all appliance manufacturers to state the degree and type of leakage their appliances emitted?
That's why I install RCBO boards nowadays. Great video as always, thanks
Thanks much. 👍
DCM305e is a great bit of kit, use mine a fair bit, really handy in 3 phase diss boards
I genuinely love it, have to stop myself obsessively measuring random currents for no reason.
Would you clamp all 3 lines and the neutral or clamp each line and neutral separately in a 3 phase dB scenario?
@@efixx it's not just me then haha it's paid for itself time and time again
@@carlgrooby4083 you can do either, just a bloody good indication of where to look before starting fault finding i use the DCM340 to help with load balancing on older 3 phase boards that have been constantly added too
How do you apply the clamp meter when you have MCB’s rather than RCBO’s?
is there an allowable max leakage current value in the code in order to stay safe ?
Thank you 😊
interesting af. Thank you 🙂
Thanks for commenting!
That's great in all but when changing a mains board I always carry out an insulation test test anyway, I have been caught out way too many times even if a sparky says they tested it a couple days before I get there
Use my megger leakage tester all the time. Had a problem with a large office block that had extremely poor loading of sockets for the computers. Made a Earth cable out extension lead and plugged in everything eventually it was a laptop charger causing the leakage current. With out this I don’t think I would of found the fault.
Great info 👍
I don't see how you can use it without rcbo. Your line and neutral wires are usually separated in the electric cabinet when usual mcbs are used. The cable from the appliance usually include earth wire, so loop meter will show 0 .
@@eugeneeugene3313 my explanation wasn’t great. I made a single socket with a plug on the end. In the middle of the cable I opened up the flex to expose the inner cables. Pulled the cpc out of the way leaving only line and neutral in the flex for about 6 inches. Put clamp meter around the line and neutral. Plug appliance in to socket and plug in to a power outlet.
@@Beariam24 Thank you - good trick. If I understand correctly, you actually build an extension cord so that line and neutral wires are not bundled together with earth (ground) wire. So you can encircle with tester loop just the line (live) and natural wire while connecting the appliance via this "exposed" extension cord. Is it correct?
I work in events providing large modular LED screens to events and gigs. We can have over 200 switch mode psu’s on a screen (1 per cabinet), each dumping their little bit of current to earth. We have to factor in the number of cabinets per RCBO and can end up with 48 or 72 channels running to the screen over socapex multi pin connectors and cables fed from 125a or 250a three phase supplies. Nuisance tripping isn’t wanted when you could loose the screen behind the headline artist….
What about those 100A blocks splitting tails inside meter box? Last video about EV's installs, you guys said that equipment shouldn't be installed inside there. How to go around those situations?
I was thinking the same..
More info on that coming soon - in short if the meter installer complained they would have to be moved
Given it's use case you'd think that meter would have a wireless connection so you could monitor while unplugging/disconnecting stuff, can't otherwise see what make it better than any clamp meter other than the larger jaws.
This would have been handy in I think 2017 or 2018. I had a meter at that time I don't know if it had the scale that I needed. I was working on a film and doing data management data wrinkling. I pulled up in my van set up and ran 100 foot cord to an RV and older RV. That RV then plugged into an RV socket. After a day or two of doing this I tripped the rcd (we call them GFCI's or GFI for short) and I had to track it down in the RV to an outlet buried somewhere I think it was either by the electrical panel or sink. All the outlets or on this one circuit it was an older RV and an older GFCI. After finding that I ran 200 feet of extension cord to the only other outlet other than the one running the coffee maker ( an extremely important appliance unless you drink tea like I do but I didn't wanna get out anybody's bedside either). Would've loved to known whether that GFCI was just getting faulty with age and cranky with the long cable run or maybe I got some moisture in one of the junctions I don't know. I just know I had to get the production management trailer back on line before I could do anything else as that was essential and the only place with outlets are than the one under the coffee maker outside and the one other dedicated outlet I found. See the biggest problem is we test the functionality occasionally and we're supposed to test monthly according to the instructions the manuals and documentation and even printed on the devices but that doesn't happen and that's just a functionality test. I'm sure more industrial like places might have the money to put forth into higher test requirements but generally homes and businesses as long as it's working, it's done right and meets code.
hi ham radio lightning eathing whot is the set up is it to mains or to a roads to ground
Could you in theory camp this around a sub main including an earth, and then proceed as you did by eliminating loads? And also where could you find a rated earth leakage value on electronic components if you were designing circuits incorporating IT equipment?!
I would imagine you could not clamp this around a sub main including an earth & get an accurate reading. The device is looking for a difference in the electromagnetic field produced by the current flowing through the wires. If you have say 10 Amps flowing through the Live conductor, and only 9.98A flowing through the Neutral conductor, you have a leakage current of 20mA and that is presumed to be going to Earth. If you assume that 20mA is going through the earth cable, then the electromagnetic fields produced by the current flowing through the three wires (live in, neutral & earth out) will cancel out & therefore the meter will read 0. Also I have yet to see any IT equipment give a rated Earth Leakage current. It really depends on the circuit design & quality of the components making up the circuit. Some Y class capacitors may leak more than others.
Thanks dude!
My pleasure! 😃
Another nice video.. well explained. I know this is an AC leakage meter but I’m wondering if DC is getting leaked onto the system by the likes of electronics, this is effecting the AC return current missing right? So with the likes of worrying if DC may stun an RCD will this device help? I’ve actually just bought this meter and it’s handy for pricing a non RCD to new CCU.
I don't know about that specific tool, but there are clamp meters that will measure DC current, using a hall effect sensor instead of a current transformer. However they tend to be very sensitive to external magnetic fields and even the position of the conductors within the clamp so measuring small currents can be challenging.
Interesting video. So your PC is leaking while it isn't turned on? Is that fully off or standby? Since you unplug the cable, I assume it was off while it was leaking the 0,6mA. Slightly related question. My macbook is okay when powered on battery, but when I use the extension to 220v, the metal casing of the Mac starts to have static load.. tingling feel when I slide my fingers over the surface. Mac extension cables don't have earth. I assume this would have been solved if Mac's would use earthing? (I've had this with every other Macbook before as well, not just the current one)
If in the scenario demonstrated your leakage load was tripping how would you fix it if you only have one RCD and the device is operating safely and as designed just an accumulated leakage? What options do I have.
Question for you guys, I’m a sparky & had an interesting conversation with a wholesaler today about electric vehicles. According to the rep different manufacturers use there own plugs on there vehicles, now I assumed ( apparently wrong) the there was an industry standard plug?
@@efixx cheers guys, great videos the company I work for are just getting started in installing EV. So your videos have been a great help
Cheers Tony - More EV stuff coming soon
Hi can we use it to measure earth leakage in the vessel/ship electrical system where there's no neutral??
Might not get a response to this question but when testing outside in the meter box. If you connect around the main earth would that not give the same reading as it’s downstream of all protective bonding which in most cases terminated in the mains?
A percentage of the earth leakage current will flow back via pipe work - water & gas etc so won’t be picked up by clamping around the earth tail.
Good video! Slightly off topic, but what are your thoughts about high integrity earthing applied to PC equipment? In many commercial office projects, UK engineers love to employ multiple earth paths for circuits powering desk mounted computers (commonly citing 3.5mA leakage current allowance per PC). The part of the video where you turned off the PC and saw a drop in leakage current of approx 0.7mA confirms what I suspected (for many years); relatively modern computers leak a small amount of current, but no where near the 3.5mA figure commonly quoted. The "limiting to 8 PC's per circuit" is a decent rule of thumb, and again in practice I don't see many office installations where you connect more than 8-12 PC's per circuit (especially in open plan office environments). Furthermore, I can't say I've seen high integrity earthing done in any other country where the British Standards aren't enforced...perhaps this is another British practice that isn't in keeping with the rest of the world?
It's a good point, probably as IT equipment gets a little better quality we may see a reduction in the stringency of this.
Yes we will take a look at the topic!
Thanks! I think it would be interesting (video idea perhaps?) to see what the leakage currents of various household devices are (ie a laptop, phone charger, fridge, microwave etc etc). I can’t say I’ve seen many (if any) high integrity installations in a domestic premise, but given the quantity of comments regarding leakage currents, it may help sparkies in the future know what typical leakage currents of appliances are when trying to trace nuisance tripping, or running new circuits.
@@horatiupogoreanu6422 Yes, agree there will be differences in current from brand to brand. What I'm suggesting is moreso a general overview of what (typically) are low and high leakage devices are. Hopefully it'll help with trouble shooting!
abso-phuk-en-lutely i use a high sensitivity current clamp that does ac & dc for sniff around its fantastic..
Megger really need to have removable clamp teeth and add both a hard clamp teeth and a flexible coil to enable you to get easily into difficult to reach places and small spaces with this meter. Second, here in the USA most of the electrical manufacturers are accommodating these issues in the latest electronic and hybrid electronic and hydraulic GFCIs we have them trip much faster and much lower currents around 3-4mA in 3-5 mS. How are they doing this without getting more and more unwanted tripping? Well because the GFCIs are detecting not just the amount of the minuscule DC leakage but they are detecting the whole signal, identifying the various types of surges and transients. Moreover the GFCIs are themselves self testing several times a day. In the UK many RCDs and the regulation does not help here tend to specify at least a 30mA RCDs, or RCBOs at installation time it’s all cost driven and in my view hinders the take up of more latest generation RCDs that trip much faster and much lower leakage currents. Making them much safer than the older generation ones. Efixx should be looking at these issues and really this is going into the the power quality area and I don’t mean power efficiency aspects but real identification of problematic PQ matters. Of course that requires more sophisticated expensive equipment at least if you want to do lots of PQ issues and have accuracy. This is still way too much solely a industrial or solar PV, EV issue. We need more sophisticated and affordable residential PQ meters with good mathematical signal analysis software built in. This will be also important when coming to design electrical circuits and consideration of loads. At some point in the UK you will go to larger boards as you design circuits more with device specific loads on them.
Great viewpoint and information, thanks for sharing! 😊
Could some of the leakage current be down to a capacitive effect and slight insulation breakdown of line to earth within a twin and earth?
Ver possible and very likely actually. I suspect that's what the remaining current at the end of the video was down to. 👍
Especially when the T&E has moisture inside it, seen this a few times. Insulation resistance test should pick that up too of course.
@@muzikman2008 I'm currently trying to fault-find T&E installed in plastic conduit inside a garden wall (i.e. subject to moisture). The line is connected to an RCBO in a covered area (shed) and that CU is connected to an MCB in another CU downstream. Your comment about moisture has now got me thinking. May need to do an insulation resistance test...
I have one, I have used it once. All other times I have used my experience to identify the faults.
RCBOs which have functional earth connections can be a cause of earth leakage via their earth, which can be an issue if there is another RCD upstream. I measured about 1mA - don't recall which brand.
Great point - we’ve just fitted a load of them here -
kzhead.info/sun/Zc2SZ7SlfmhseIE/bejne.html we are back at that site soon so we’ll see what we can measure.
@@henrytwigger2245 odd isnt it.though they all seem to have got rid of them now.
The earth fly lead on rcbos allows them to operate if the supply neutral is lost/disconnected.
Greatttt video