New 2017 Macbook Pro 15 Inch giving me static electric shock. Is it normal? - Page 1
Forum section: electronics / beginners

author: nasserprofessional
author_rank: Newbie
timestamp: August 29, 2017, 11:47:12 am
content: I recently bought a new Apple Macbook Pro 2017. When its plugged in charging I am getting an electro static shock from the aluminum body of the device. I have other aluminum apple laptops that dont give me static electric shock even if they are plugged into the same outlet etc.I bought the laptop from Currys PC World here in the United Kingdom, England.They insisted this is normal for Apple Macbook Pros and refused to give me a refund or replacement even though I am within the 21 days return period?Is it normal to get an electro static shock from an Apple Macbook Pro 2017 15 inch?I thought static electricity and elctrostatic discharge damages electronics/chips etc, thats why they have anti static packaging and anti static straps.I would like to see what the electronics community has to say about this.Sorry I hope I am not breaking any rules of the forum. I am extremley new to the forum but have watched Daves EEVBlog Youtube channel for a long time and would like your help.

author: wraper
author_rank: Unknown
timestamp: August 29, 2017, 12:19:37 pm
content: Does this happen when you are not touching anything else and is only a single shock and don't repeat if you touch again? Or is it a tingle feeling when you touch laptop and some other metal surface simultaneously?

author: nasserprofessional
author_rank: Newbie
timestamp: August 29, 2017, 12:43:23 pm
content: It only happens when the laptop is plugged in/charging.If I touch the laptop I can feel it the whole time I am touching the laptop.Does it get discharged when I touch it? No, If I touch it again I can instantly feel it again so its still there the whole time and isnt getting discharged or anything.It happens even if I am not touching any other surfaces while touching the laptop.It happens even if I touch another surface thats grounded for example the wooden desk, the wall etc.I have another Macbook Pro with an aluminium body I have tested that on the same surface, the same power socket, even had them side by side plugged into the same socket and if I touch the new apple laptop I can feel it if I touch the other apple laptop I dont feel it.At first I thought maybe its just me so I let my mum and sister touch it and they both felt it as well.I took it back to the store and they plugged it in, at first they denied everything said they couldnt feel a thing, they said nothing wrong with it but I could still feel the static electric or whatever it is going through the aluminum case even when it was plugged in at their store. Eventually after I kept insisting I could feel static electric or something they admitted they could feel it as well but insisted it was normal and that they all had apple laptops at home that do this.I went upto the models they had on display and they didnt seem to have any issues. Not really sure whats going on but I believe its not normal as my other one isnt doing it at all.They basically refused to do anything so eventually I walked out the store disappointed and I am trying to still talk to them about it. Just trying to find out if its really faulty or not.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: August 29, 2017, 01:33:50 pm
content: Almost certainly Class Y leakage. Yes it's normal but you seem sensitive or their new charger is more susceptible to it. We've had this discussion in another thread regarding the missing ground pin; I can't remember which thread.Measure the AC voltage between chassis and Earth and you're maybe seeing 60V+.And next time tell the Apple idiot your statutory rights.

author: grumpydoc
author_rank: Super Contributor
timestamp: August 29, 2017, 01:45:37 pm
content: It does not sound like a static shock, but rather you are feeling the small leakage current which flows through the EMI suppression capacitor in the charger.However it is possible that the charger is faulty so it might be worth getting it tested by an electrician.Or just try another charger.

author: nasserprofessional
author_rank: Newbie
timestamp: August 29, 2017, 01:59:50 pm
content: I also borrowed and tried a friends identical Macbook Pro 15 inch 2017 model with exact same specs in the same socket on the same surface and it doesnt have the same problem.Im not sure if its to do with the earth. I dont think its to do with the earth though because I have another apple laptop that has a USA 2 pin plug on it so when thats plugged into a US to UK adapter into the same socket its definitely not earthed and even that doesnt give me a static electric shock?Why is the brand new one giving me a static electric shock?Just to be sure I also added the USA plug from the old laptop onto his new laptop and even after his new laptop definitely wasnt earthed it didnt do the static electric shock thing so I dont know whats going on.What rights do I have btw, Just so I can tell those Currys PC World... guys?

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: August 29, 2017, 02:01:13 pm
content: The thing with those shitty apple chargers is, that you need to use a three prong extension cord on them. With the two prong plug that comes with it the aluminium housing is not grounded (?) and there is electricity flowing on the surface.Edit: Maybe it has to do with the phase and neutral prong also. I did not try that, but it might be possible that one way you are getting leakage current and plugged in the other way there is no leakage current.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: August 29, 2017, 02:02:53 pm
content: Do you have a multimeter with AC range?

author: Ian.M
author_rank: Super Contributor
timestamp: August 29, 2017, 02:11:49 pm
content: https://www.eevblog.com/forum/chat/does-this-sound-acceptable-for-an-apple-product/Seehttps://www.instrumart.com/assets/Megger-Portable-Appliance-Testing-Guide.pdf, page 20 Table 4. If the supplied adaptor doesn't connect the Ground to the PSU stud, then it must meet the class II limit for touch current and if you measure more than 0.25mA AC between chassis and a good Earth, take it back and reject it as "Faulty, unsafe and not fit for purpose.". Return it about 9:30am*on a weekday ASAP, take a credible witness, and in case you have any problems, have your local Trading Standards on speed dial and your phone on speakerphone!https://en.wikipedia.org/wiki/Consumer_Rights_Act_2015sets out your right to a full refund within 30 days of purchase.However odds are it will creep in under the threshold.* So your local Trading Standards Officer has got into work, had his/her coffee and woken up!

author: wraper
author_rank: Unknown
timestamp: August 29, 2017, 02:42:42 pm
content: Quote from: nasserprofessional on August 29, 2017, 01:59:50 pmThis is not static but current leakage, through Y capacitors. Have you tried changing only charger? The issue most likely connected with it. If other charger plugged in your laptop and the same socket does not experience this, there may be something wrong with your charger or it may be made by different supplier as Apple uses several PSU manufacturers.

author: grouchobyte
author_rank: Regular Contributor
timestamp: August 29, 2017, 02:51:55 pm
content: Could be caused by a number of things. The hints in this thread might be helpful, but I would contact Apple first and foremost, since they are liable if you or someone else is hurt by this laptop.My first thought when I read the OP post was "sticker shock" ....ouch! (We need an emoticon for that)@grouchobyte

author: Ian.M
author_rank: Super Contributor
timestamp: August 29, 2017, 02:55:26 pm
content: No. Under UK law within 30 days of purchase, the O.P.'s first recourse is the shop that sold it.Seehttp://www.legislation.gov.uk/ukpga/2015/15/section/22IANAL

author: brucehoult
author_rank: Super Contributor
timestamp: August 29, 2017, 03:39:49 pm
content: I've had this with my 2011 17" MBP from time to time. It's sub-milliamp leakage current from the chassis not being at ground potential. In my experience it's nothing like a static shock. It feels more like getting a hair on my hands caught in a crack and being pulled. Mostly I notice it when I'm moving my hands across the surface, not keeping them still. It seems to depend upon where and how I plug it in. Right now it's plugged in to an Apple 85W power supply to a NZ/Aus 3 pin lead to a NZ plugboard, to a cheap adaptor, to a Russian plugboard, to an extension cable, to the Russian/Euro earthed wall socket ("Schuko" I believe they're called). No problems.

author: amyk
author_rank: Super Contributor
timestamp: August 29, 2017, 04:25:31 pm
content: Yes, definitely the leakage current through the EMI suppression capacitor:http://www.aplomb.nl/SMPS_leakage/Doc_ie.htmlMeasure it with a multimeter. Feeling it doesn't mean it's unsafe, but you should still get a replacement if you don't like it. Some people are more sensitive than others.

author: jmelson
author_rank: Super Contributor
timestamp: August 29, 2017, 04:31:01 pm
content: Quote from: nasserprofessional on August 29, 2017, 01:59:50 pmREPLACE your charger immediately! It has electrical leakage. If you ever were to touch the computer and something grounded at the same time, you might get a serious shock. If you can feel that electrical charge when you are not touching something grounded, then the case of the machine is likely at line potential. You could check just the friend's CHARGER with your computer, and I'd give you a 99+% probability that you would not get the shock. The problem has to be in the charger.Jon

author: Vtile
author_rank: Super Contributor
timestamp: August 29, 2017, 05:23:50 pm
content: Quote from: RGB255_0_0 on August 29, 2017, 01:33:50 pmI would guess the float or not your scope.

author: electrolust
author_rank: Unknown
timestamp: August 29, 2017, 06:00:47 pm
content: Quote from: nasserprofessional on August 29, 2017, 11:47:12 amObviously this is not normal. I assume you are using the Apple charger and not a 3rd party charger.Too bad you didn't buy it from an Apple store. Here in the US, and I suspect worldwide, I'm not sure of the time period but the return policy is for any reason whatsoever. Since the apple store has a no questions asked policy, I'm surprised that 3rd party retailers aren't obliged to have the same return policy.You might be lucky and it's just the charger. So you'll be out the $50 or whatever but the fix is relatively cheap even without vendor support. And don't buy from them again and give them a 0 star review.

author: grumpydoc
author_rank: Super Contributor
timestamp: August 29, 2017, 07:11:50 pm
content: Quote from: nasserprofessional on August 29, 2017, 11:47:12 amIf it is through the EMI suppression capacitor then a small amount of currentisnormal and allowed for in the safety standards.However the fact that you can feel it on one macbook/charger combination but not another is suspicious that the charger is faulty.Take it to an electrician who can do portable appliance testing - if it is outside the leakage limit (250uA if the charger is double insulated and has no earth connection) then you have a claim against the retailer.If the charger is actually faulty then this claim is not limited to 30 days.

author: electrolust
author_rank: Unknown
timestamp: August 29, 2017, 08:05:52 pm
content: Quote from: grumpydoc on August 29, 2017, 07:11:50 pmNormal vs. Allowed.Allowed to the level that you would feel it? With all the attention that Apple gets, if this were "normal" for apple products, the tech press would be all over it. There is no possibility that this is normal.

author: bd139
author_rank: Super Contributor
timestamp: August 29, 2017, 08:10:56 pm
content: Leakage on them is terrible. Periodically when I'm soldering my left elbow rests on the MacBook and also ends up feeding solder. You get an unpleasant tingle when you apply the iron.This is normal. It's just shit.Mine is 15" 2013 MBP bought from Apple Store.If you take it back you'll get another one that does the same. Current is around 100uA max from what I measured at around 90v ac RMS. And it's normal SMPS leakage.Incidentally my Thinkpad T440 does this but you don't notice it usually because the unit is entirely plastic. If you touch a port you will feel it.Edit: before I forget, this caused havoc with an arduino I was using with an isolated floating supply. It caused the ADC to be entirely useless. I grounded the power supply and it was fine (and no more zaps)

author: jmelson
author_rank: Super Contributor
timestamp: August 29, 2017, 09:51:34 pm
content: Quote from: grumpydoc on August 29, 2017, 07:11:50 pmI really doubt the leakage is below 250 uA, or the OP would have been very unlikely to feel it. I suspect it is WAY more than that.Jon

author: wraper
author_rank: Unknown
timestamp: August 29, 2017, 10:10:27 pm
content: Quote from: jmelson on August 29, 2017, 09:51:34 pm0.25mA feels quiet noticeably when current passes through you.

author: John B
author_rank: Frequent Contributor
timestamp: August 29, 2017, 10:14:49 pm
content: If you can't get an earthed 3 prong snub-nose adapter, you can always buy a cheap chinese 3 prong ~1.5m lead and then just trim the lead and put your own 3 prong connector on. That's how I made a short lead for the apple PSU.As above, it's normal, but it's annoying. The tingling, even stinging feeling seems to punch well above its weight for what the 100-250uA RMS would seem to imply. When I made my thread I only measured current with a multimeter, I didn't examine the waveform.Also worth noting, of the macbooks Ive tested, the chassis isn't conductive. Despite looking metallic, it's powder coated with an insulator, so the current is capacitively coupled.To that end, the surface area of what is touching the chassis will influence the current you feel. If you directly touch the chassis with a probe lead, the voltage and current will be less compared to placing a metal plate on the chassis then touching your probe to that.

author: electrolust
author_rank: Unknown
timestamp: August 29, 2017, 11:18:36 pm
content: Quote from: wraper on August 29, 2017, 10:10:27 pmthe number being discussed is .000250A, not .250A

author: electrolust
author_rank: Unknown
timestamp: August 29, 2017, 11:20:52 pm
content: many discussions about this if you google search. apparently it is not uncommon for non-3-prong plugs. I think the apple charger itself is only 2 prong if you don't use the long extension cable.

author: wraper
author_rank: Unknown
timestamp: August 29, 2017, 11:33:58 pm
content: Quote from: electrolust on August 29, 2017, 11:18:36 pmObviously that was a typo and 250uA = 0.25mA was meant. ) 0.25A will fry you, and if passes from hand to hand, very likely kill.

author: amyk
author_rank: Super Contributor
timestamp: August 30, 2017, 02:07:45 am
content: Quote from: jmelson on August 29, 2017, 09:51:34 pmDifferent people have varying sensitivity to currents passing through them, and also varying resistance. If you search around you will find plenty of others saying they can feel it too.Due to the safety standard of 250uA they may have designed it to put almost 250uA into a dead short (the higher the cap value, the better the EMI suppression), but with a human and its resistance in the circuit, that number can only drop. And 250uA is definitely noticeable.

author: Ian.M
author_rank: Super Contributor
timestamp: August 30, 2017, 05:51:08 am
content: It needs testing. If it reads above about 200uA on an ordinary DMM, its worth getting it tested by an electrician with a calibrated PAT tester who can certify whether or not it is defective. Start by measuring voltage across a 10K resistor to avoid blowing your DMM if its *far* more than 250uA. Accross 10K, you get 1V per 100uA.If its even 1uA over the permitted limit you can reject it as defective. However as I stated earlier I suspect it will creep in under the limit and the only option will be to get an Apple adapter for the PSU that grounds it effectively.

author: electrolust
author_rank: Unknown
timestamp: August 30, 2017, 06:21:39 am
content: Quote from: wraper on August 29, 2017, 11:33:58 pmYou changed the prefix (for some reason), and this is the beginner section. So no, it was not obviously a typo. For example, it wasn't obvious to me, a beginner.You did cause me to google it, and the top result ishttps://www.physics.ohio-state.edu/~p616/safety/fatal_current.htmlwhich claims that 100-200mA is deadly due to v.fib, whereas above 200mA has very good survivability as the heart stops at higher currents.

author: wraper
author_rank: Unknown
timestamp: August 30, 2017, 08:47:44 am
content: Quote from: electrolust on August 30, 2017, 06:21:39 amI changed units for a reason that uA may look like very small current for some people (beginners). If I quote a current value, and write the same value but in different units and miss a letter while typing, it's a typo. The fact that something is not obvious to you, means only that you should learn more. Not that a typo magically stops being a typo.

author: wraper
author_rank: Unknown
timestamp: August 30, 2017, 08:51:51 am
content: Quote from: electrolust on August 30, 2017, 06:21:39 amOnly if somebody makes a heart massage for you. Otherwise you have nearly zero chance survive with stopped heart and not breathing. Also I'm dubious about so narrow current range considered as fatal.

author: Gyro
author_rank: Super Contributor
timestamp: August 30, 2017, 09:46:08 am
content: Quote from: wraper on August 30, 2017, 08:47:44 am@wraper: If you're going to get all shirty about it...You should be sticking to standard SI / Engineering notation (even more so for beginners). We don't talk about 0.25M resistors, we say 250k. We don't use 0.25kV when we mean 250V etc.250uA is the appropriate notation in this case.

author: Ian.M
author_rank: Super Contributor
timestamp: August 30, 2017, 11:00:48 am
content: <PEDANT>Actually, the applicable standard:IEC 60950-1 "Information technology equipment – Safety"quotes the touch current limits in mA.even though some are under 1 mA.A copy of the English pages of IEC 60950-1 2nd ed. 2005 can be found.Page 357 (PDF page 181)</PEDANT>

author: Gyro
author_rank: Super Contributor
timestamp: August 30, 2017, 11:30:13 am
content: Quote from: Ian.M on August 30, 2017, 11:00:48 am<Fellow Pedant>Yes, I guess they have an excuse in that case because they have >1mA values appearing in the same column. Doing otherwise would be more confusing.</Fellow Pedant>

author: wraper
author_rank: Unknown
timestamp: August 30, 2017, 11:28:05 pm
content: Current leakage value in uA units does not make sense as region of interest/danger lies in mA region. Also regarding:Quote from: Gyro on August 30, 2017, 09:46:08 amWhy engineers are using0.1uF capacitors for decoupling? And 0.1uF naming is mentioned more often used than 100nF. BTW it's even more common for markings on capacitors. I'm sure that you definitely should tell engineers and manufacturers that all of them are wrong. And for sure you should tell to those who made that 0.05 ohm resistor instead of 50 mohm, they they are complete idiots.

author: Gyro
author_rank: Super Contributor
timestamp: August 31, 2017, 08:27:41 am
content: Who knowsHistorical reasons? I guess only the manufacturers could have an answer for that. I could pull out an equal number of caps from my parts box that use the correct notation, those that don't use IEC notation of course. At least the US maufacturers seem to have stopped using mF when they mean uF. It's certainly something you don't want people littering new schematics with.The above is no excuse for us not using and promoting correct engineering notation here though, particularly for fundamentals like voltage and current.P.S.I see 100nF used a lot more than 0.1uF in discussion and schematics, I certainly don't see 0.01uF used instead of 10nF these days (as used to be common in the past). maybe a geographical thing.@nasserprofessional:Sorry for the diversion.

author: bd139
author_rank: Super Contributor
timestamp: August 31, 2017, 09:52:49 am
content: I noticed this. Americans historically used mmf and mf as measurements of capacitors (pF and uF) only and half the time they don't even add the units. This seems to have turned into a defacto standard in American literature. Then you have to decipher whether "47" means 47pF or 47uF. Here in Europe we adopted all of the correct symbols: F, mF, uF, nF, pF. 47u, 47p. Problem solved. Ultimately there should be no leading decimal portion of the number - just use the correct units!Again diversion offJust measured current between my ThinkPad T440 and ground: 82uA.And the MacBook again: 103uANow my desk lamp which is a cheap shitty switch mode driven LED thing: 8uA.Now I'm soaking wet after having just got out of the shower so not the best time to measure this

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: August 31, 2017, 10:14:17 am
content: Quote from: bd139 on August 31, 2017, 09:52:49 amI prefer the decimal point. Sometimes I go blind to the p/u/m if there are so many and have to go back and correct itAt least if you stick to, say, micro you don't even need to read the postfix.Maybe I'm careless.

author: Gyro
author_rank: Super Contributor
timestamp: August 31, 2017, 11:19:15 am
content: Quote from: RGB255_0_0 on August 31, 2017, 10:14:17 amYep....Or just old like me!

author: electrolust
author_rank: Unknown
timestamp: August 31, 2017, 05:00:34 pm
content: Quote from: wraper on August 30, 2017, 08:47:44 amhuh?I didn't say it wasn't a typo. I said it wasn'tobviouslya typo. I don't know what the palm is about buddy, get over yourself.It was an error and it wasn't obvious if, as a beginner with no gauge of what is "big" current esp wrt the human body, it was an error in units (a typo) or an error in quick reading (a thinko). 0.25mA also looks like "very small current", to a beginner without an appreciation of a milliamp. In fact due to the decimal it "looks" smaller than 250uA (no decimal), so I think you went the wrong direction if your intent was to make the value look "bigger".

author: wraper
author_rank: Unknown
timestamp: August 31, 2017, 05:17:55 pm
content: Quote from: electrolust on August 31, 2017, 05:00:34 pmThen it was a language barrier. And you wrote it in confusing way, and I'm not sure if grammatically correct, English is not my first and even not a second language. Now tried google translate, and it agrees with how I understood it (obviously, it was not a typo). If you wrote "it was notobvioustypo" then I would understood you properly.

author: electrolust
author_rank: Unknown
timestamp: August 31, 2017, 05:25:07 pm
content: Quote from: bd139 on August 31, 2017, 09:52:49 amI thought T-series were all plastic bodied? Mind saying where exactly you measured on the case? Can you feel the103uA0.103mA?You inspired me. I have a new USB-C MB from work, charging with Apple 2 prong adapter, and the current between case and ground is ... unmeasurable. Am I doing it right? I'm using the uA DC range, hot lead touching the MB case and ground lead touching the metal of a wrist static band that plugs into a wall outlet ground plug. On the ACV setting I do measure 110V between hot and the the wrist band (ground plug), so for sure the ground wire is connected in the outlet.From what I can gather, there should definitely be SOME leakage current, so I must be measuring it incorrectly? Or is it possible that my charger doesn't in fact leak.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: August 31, 2017, 05:39:53 pm
content: Well there isn't going to be DC through the cap

author: electrolust
author_rank: Unknown
timestamp: August 31, 2017, 06:01:00 pm
content: Still no current using ACI measurement. The laptop is fully charged though, so perhaps it's turned off the charging function. I'll let the battery drain a bit.

author: electrolust
author_rank: Unknown
timestamp: August 31, 2017, 07:32:36 pm
content: 0.200uA (200nA) measured with just the probes touching. If I press the positive probe to the case with my finger, it goes to 15ua. 25nA if I put myself in the loop -- hot lead to case, gnd lead in hand, wrist strap to ground.I'm using a miniature charger though, 29W or something like that. Not the bigger 61W or 87W chargers.

author: Ian.M
author_rank: Super Contributor
timestamp: August 31, 2017, 07:59:00 pm
content: From the PDF of the IEC 60950-1 standard I linked in reply#34Quote from: IEC 60950-1 Section 5.14So, to get a repeatable and reproducible measurement, if you cant get good metal to metal contact between the D.U.T and your probe, cut a strip of Aluminum foil of those dimensions, take some hookup wire, strip the end, fan the strands and tape it to the middle of the foil for a convenient connection point, and push the foil (wire side up) against the surface of the D.U.T. using something soft and insulating. e.g a sealed plastic bag full of air, a dry soft sponge in a plastic bag or a balloon. Also, record the mains voltage when you perform the test.

author: ciccio
author_rank: Frequent Contributor
timestamp: August 31, 2017, 08:20:13 pm
content: Years ago I had a similar problem with a Toshiba laptop.I was using it to control a loudspeaker processor via the RS232 interface, an when the laptop was mains powered, via a brick with a two-prong plug, I got a noisy ground that resulted in a lot of TX-RX errors (it also lighted the neon on my test screwdriver)A quick solution was an isolation transformer connecting the mains socket to the power brick (with no earth wire).(The controller was mains powered, but it's earth came from a socket located at about 50 meters from me and the circuit ground was connected to earth via 100R//100nF, as was usual in audio equipment in these years)Best regards

author: Vtile
author_rank: Super Contributor
timestamp: August 31, 2017, 08:27:29 pm
content: Quote from: Ian.M on August 31, 2017, 07:59:00 pmThis foil method is almost same as (were?) used to measure the conductivity of electrical laboratory surfaces, IIRC it were from some (old) standard, but can't again recal if it were national or international. The method did came to me as 2nd hand knowledge, but from trustworth oral source.Thanks for the post, writing that to my notebook.PS.Does the IEC 60950-1 mention anything about current shunt resistor in this case?I just noticed the link...

author: bd139
author_rank: Super Contributor
timestamp: September 01, 2017, 09:33:32 am
content: Quote from: electrolust on August 31, 2017, 05:25:07 pmT series is plastic bodied although the ports have metal contacts. In this case I plugged a metal USB stick in and measured from that as it's connected to the inner frame.

author: pedro380085
author_rank: Newbie
timestamp: November 13, 2019, 10:24:32 pm
content: IF we replace the charger, the problem should go away? Or the macbook pro unit is also damaged and needs repairing?

author: tooki
author_rank: Super Contributor
timestamp: November 14, 2019, 12:21:42 am
content: I don’t think you understood the existing discussion. The tingle is normal for these units (like with most switching power supplies) when used without a real earth ground. So no, replacing the adapter won’t change anything, because it’s not malfunctioning. Nor is the MacBook faulty. If the tingling bothers you, get the 3-pin power cord and make sure your outlet is properly grounded.