New 2017 Macbook Pro 15 Inch giving me static electric shock. Is it normal?

[wraper]

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.

I 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

0.25A feels quiet noticeably when current passes through you.

the number being discussed is .000250A, not .250A

Obviously 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.

[amyk]

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.

I 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

Different 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.

[Ian.M]

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.

[electrolust]

Obviously 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.

You 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 is https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html which claims that 100-200mA is deadly due to v.fib, whereas above 200mA has very good survivability as the heart stops at higher currents.

[wraper]

You 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.   

I 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.

[wraper]

You did cause me to google it, and the top result is https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html which claims that 100-200mA is deadly due to v.fib, whereas above 200mA has very good survivability as the heart stops at higher currents.

Only 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.

[Gyro]

I changed units for a reason that uA may look like very small current for some people (beginners).

@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.

[Ian.M]

<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 [here].

Page 357 (PDF page 181)

</PEDANT>

[Gyro]

<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. 
....
</PEDANT>

<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> 

[wraper]

Current leakage value in uA units does not make sense as region of interest/danger lies in mA region. Also regarding:

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.

Why engineers are using 0.1uF 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.

[Gyro]

Who knows  Historical 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.

[bd139]

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 off

Just measured current between my ThinkPad T440 and ground: 82uA.

And the MacBook again: 103uA

Now 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 

[RGB255_0_0]

Ultimately there should be no leading decimal portion of the number - just use the correct units!

I 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 it 

At least if you stick to, say, micro you don't even need to read the postfix.

Maybe I'm careless. 

[Gyro]

Maybe I'm careless. 

Yep      ....Or just old like me!

[electrolust]

You 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.   

I 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.

huh?

I didn't say it wasn't a typo.  I said it wasn't obviously a 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".

[wraper]

I didn't say it wasn't a typo.  I said it wasn't obviously a typo.  I don't know what the palm is about buddy, get over yourself.

Then 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 not obvious typo" then I would understood you properly.

[electrolust]

Just measured current between my ThinkPad T440 and ground: 82uA.

And the MacBook again: 103uA

I thought T-series were all plastic bodied?  Mind saying where exactly you measured on the case?  Can you feel the 103uA 0.103mA?

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.

[RGB255_0_0]

Well there isn't going to be DC through the cap 

[electrolust]

 

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.

[electrolust]

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.

[Ian.M]

From the PDF of the IEC 60950-1 standard I linked in reply#34

For an accessible non-conductive part, the test is made to metal foil having dimensions of 100 mm by 200 mm in contact with the part. If the area of the foil is smaller than the surface under test, the foil is moved so as to test all parts of the surface. Where adhesive metal foil is used, the adhesive shall be conductive. Precautions are taken to prevent the metal foil from affecting the heat dissipation of the equipment.

So, 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.

[ciccio]

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

[Vtile]

... snip .. PDF ...

This 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...

[bd139]

Just measured current between my ThinkPad T440 and ground: 82uA.

And the MacBook again: 103uA

I thought T-series were all plastic bodied?  Mind saying where exactly you measured on the case?  Can you feel the 103uA 0.103mA?

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.

T 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.

[pedro380085]

IF we replace the charger, the problem should go away? Or the macbook pro unit is also damaged and needs repairing?