[forumhound]

Odd question, I know, but I have noticed that by running my finger tip across the base area of my macbook pro I can feel a "current" or a slight vibration. Very strange. Unhooked from all power sources (including usb devices that are powered) it goes away. We have 220 here, and the power comes into the office via a small voltage controller with spike protection, then into a battery backup unit also with surge suppression, then to a power strip where the power bricks are plugged. I also have a sony tr3 with an aluminum/or metal casing, and when plugged in that one gives off the same sensation, although less noticeable. I did plug the brick in before all the regulatory devices (into a strip from the office wiring) and that was a bad mistake as the power brick was dead in a few days - but that vibration was not there while it lasted! So now i have the spare plugged into all the protection and get that tingly feeling every time i touch my laptop case (touchpad is fine). Should i be worrying?

[damiensmunki]

Dude...that sounds like a pretty damn serious problem. Sorry, but I don't have anything helpful to contribute, other than to say that...yeah...if I were you, I'd be worrying.

[forumhound]

Originally Posted by damiensmunki 

Dude...that sounds like a pretty damn serious problem. Sorry, but I don't have anything helpful to contribute, other than to say that...yeah...if I were you, I'd be worrying.

Thanks Damien - Well gosh I feel better already... i am not sure it's current, but what else could it be? dragging ur finger tip lightly over the surface, you can feel...something, not sure what it is? And it happens only when plugged in. Anyone else have an idea?

[onlyone-jc]

I'm pretty sure it's to do with earthing.

If you think of it, your entire MacBook Pro case acts as an earth (since it's metal) so, sometimes, depending on where you're getting your mains from, the earth can be a little dirty.

You could try this (in the same place you're experiencing this):

Plug some form of USB device in to your MacBook Pro that uses its own external power supply. Unplug your MacBook Pro from any mains and run it on the battery. Run your fingers across the MacBook Pro and see if you can still feel the sensation.

If its the fault of the local earth, you should still be able to feel the sensation (although, it may be slightly weaker), because the MacBook Pro is now being earthed via the USB device, albeit using the same earth.

I'm sure static electricity has something to do with it as well, since I sometimes get it when I have my computer sat on the carpet. But, it depends where I am. I don't get it from all mains outlets.

Good luck solving it, and if you find out exactly what it is and how it's caused, be sure to come back and let us know.

onlyone-jc.

[Simon]

It's already been discussed dozens of times on this board. Do a forum search.

The tingle you feel is because your MBP isn't properly grounded. You need to use the three prong cable instead of the (ungrounded) two prong duckbill. If the problem then doesn't go away your ground wiring is faulty. Get an electrician to fix it. Faulty (or missing) ground terminals are dangerous.

[forumhound]

Originally Posted by onlyone-jc 

I'm pretty sure it's to do with earthing.

If you think of it, your entire MacBook Pro case acts as an earth (since it's metal) so, sometimes, depending on where you're getting your mains from, the earth can be a little dirty.

You could try this (in the same place you're experiencing this):

Plug some form of USB device in to your MacBook Pro that uses its own external power supply. Unplug your MacBook Pro from any mains and run it on the battery. Run your fingers across the MacBook Pro and see if you can still feel the sensation.

If its the fault of the local earth, you should still be able to feel the sensation (although, it may be slightly weaker), because the MacBook Pro is now being earthed via the USB device, albeit using the same earth.
onlyone-jc.

This is exactly right. So my local earth is at fault, darn that terra firma. Were can I get a faraway one? I plug a powered usb hub in when on battery power and everything else disconnected the sensation is still there. Let me reply to the next post with questions...thx.

[forumhound]

Originally Posted by Simon 

It's already been discussed dozens of times on this board. Do a forum search.

The tingle you feel is because your MBP isn't properly grounded. You need to use the three prong cable instead of the (ungrounded) two prong duckbill. If the problem then doesn't go away your ground wiring is faulty. Get an electrician to fix it. Faulty (or missing) ground terminals are dangerous.

Simon, thanks. I found this thread but as with most threads over 1 page here answers are hard to parse:
http://forums.macnn.com/69/mac-noteb...light=tingling

I am using the 3 prong cable, but I think the problem in nepal is that no one else does. almost every power strip sold here is two prong (except for some imports). But I checked my setup and it seems everything has three prongs all the way thru (that's a stroke of luck). BUT according to the test recommended by onlyone-jc, it seems 3 prongs is irrelevant, as I get the tingle with nothing is attached but a powered usb hub and I am running the mbp on bat.

SO not to belabor this problem that seems to be pretty common, is it DANGEROUS to equipment or for people or for my german shepard? I have my mbp on an iStand and don't usually touch it when the power is on except to plug/unplug cables.

Also, what's the fix for a faulty ground if your building is at fault. If I call a nepalese electrician and explain this they will just laugh. People here are happy for just having lights and a line that does not blow out bulbs and television tubes (which happens). We have loadshedding which means every 4 hours or so when the power comes on a huge surge of electricity spikes out to flood the local wires with enough juice to power the city. It's crazy man.

Can I rig a ground internally within the house...like maybe drive a stake thru the carpet (oh that won't work, all construction here is 100% concrete) or maybe thru my heart at this point. One of the screws on the mbp case wired into the laminate on my pressboard desk?

Or should I just not worry like AE Newman...my favorite approach to all things computer.
Thanks,
CCFCCP

[analogika]

If your sockets aren't grounded, there is not much you can do short of rewiring the house.

[romeosc]

Originally Posted by analogika 

If your sockets aren't grounded, there is not much you can do short of rewiring the house.

You can get a cheap ($.50) 3 prong to 2 prong adapter. It has a green wire with a spade lug. Run wire from the green wire to cold water pipe and the plug will be grounded! Not pretty but much safer than using the situation you are in!

[forumhound]

analogika, thats a project that will have to wait until a future when there are no wires for power. BUT guess what, I DID find a power strip in my chain that while it had a 3prong plug only two were wired! This is typical for chinese junk sold here. SO after replacing that, no more tingle. BUT I have done this all in the dark running on battery backup (horse size ups). But the test mentioned above now passes with no tingle. My last and final question for this thread is this:

What is the absolute safest way to connect my mbp when the power returns? From the switch on the strip with the magsafe plugged in or not plugged in? Should I keep the 3prong powerbrick unplugged from the strip? I've already lost one of those (plugged into an unregulated line, it blew the fuse in the 3 prong and shorted the brick). I want my laptop to last thru the end of this year! thx,,,,

ps, searching thru this forum for answers to anything hardware related is plain scary. that defect page on the mbp is mindblowing, warped this - blown that - melted plugs and yellow screens oh my!

[forumhound]

Originally Posted by romeosc 

You can get a cheap ($.50) 3 prong to 2 prong adapter. It has a green wire with a spade lug. Run wire from the green wire to cold water pipe and the plug will be grounded! Not pretty but much safer than using the situation you are in!

romeo, thanks for that tip. i don't need i don't think, but glad not to, the nearest pipe is rooms away. its a problem here. i know expats who won't plug anything into a wall at all...they get the nepali help to do it. that's kinda sad...

[Sherman Homan]

Grounding isn't magic, but it does mean that the circuit breaker panel is connected to something that runs to Mother Earth. Many times it is nothing more complicated than clamping a wire to a copper water line. If the piping is plastic, there are specs for simply pounding a stainless steel rod deep enough to go below the frost line. Next problem is that you need a continuous connection from the panel to your outlet. Using a three-pronged plug where the ground isn't run correctly back to the panel is useless, unfortunately.

[forumhound]

Originally Posted by Sherman Homan 

Grounding isn't magic, but it does mean that the circuit breaker panel is connected to something that runs to Mother Earth. Many times it is nothing more complicated than clamping a wire to a copper water line. If the piping is plastic, there are specs for simply pounding a stainless steel rod deep enough to go below the frost line. Next problem is that you need a continuous connection from the panel to your outlet. Using a three-pronged plug where the ground isn't run correctly back to the panel is useless, unfortunately.

Wow, I am learning so much about raw energy here, but fortuatly things here must be grounded, I have a shockfree mbp now after tracing back all the wiring for 3 pin connections....Thank you everyone!....but like i said, finding powerstrips and even other appliances here that have is rare. They sell chinese 19" TVs with tiny little 2 prong round pins that hardly fit into any socket. Shocking

[acoustix]

Many Asian plumbing set-ups have roof tanks, so earthing is not as easy as connecting to water pipes, which can just result in giving you nice shocks while bathing. I recently had a proper earth connection installed here in India (very similar to Nepalese conditions) and it involved digging a 5 ft. deep pit, and burying salt and a heavy copper plate attached to a lead up to the surface to connect the earthing ground wires to. I had previously had electricians happily run me a green wire along with everything else when i asked that things be grounded, but there is now something to actually connect it to. When we installed a washing machine recently, I decided to bite the bullet for the sake of safety. Not getting a shock does not necessarily mean you have a proper ground which will direct the current to the breaker or fuse in the case of a dead short.

[analogika]

Note that the tingling you feel on the MacBook Pro has been present on nearly all machines since the very first metal (titanium) Powerbooks, 7 years ago.

It is - according to an Apple service rep I talked to - part of spec, and not a problem. The only solution they suggest is using the grounded extension cord.

[SierraDragon]

Poor grounding is an issue all over the world, including the US. Risk generally occurs when a secondary problem like a short occurs, the risk being if a short occurs and instead of the shorted current going to ground via proper grounding (and ideally some type of fuse) it goes to ground through a person.

Some devices are riskier than others. If the contact is good between the shorting device and the person and the person has good contact to ground and the easiest route to ground goes through a person's heart death can easily result. E.g. a 220 volt short to the metal case of a MBP held in-hand by a person with bare feat on the ground could be easily catastrophic. OTOH the same short with a plastic Macbook might have no consequence except fried MB internals.

The good news is that any number of things can help avoid setting up a potential [intentional pun] current-through-heart scenario. Easiest, most important is providing a valid ground to risky appliances like metal driers, washing machines, and metal-cased computers. If cold water piping does not go to ground a 5 foot brass ground stake can be driven into the ground, and a ground adapter plug attached. Insulating gloves, plastic device casings, shoes like rubber sandals and simply making sure devices are well maintained and do not short out all also may interrupt a fatal scenario.

IMO there is no excuse for not inexpensively modifying any given environment to avoid electrical shock, even if for no other reason than to protect expensive hardware.

-Allen Wicks

Edit: Consult local codes and good practice, do not solely rely on my suggestions above.

[Simon]

You can kill yourself with both a 12V car battery or a European 220V toaster.

It's not voltage that kills you, it's frequency or current. AC currents with the right frequencies induce ventricular fibrillation. Sufficient AC or DC currents (primarily currents above 100 mA across the heart) kill you through electrical shock (leading to cardiac arrest / myoparalysis) or (in severe cases and especially with DC current) burns.

[ghporter]

There is actually enough energy in a standard 9V alkaline battery to kill a human. The trouble is getting the electricity to where it can do the harm-and that would be INSIDE the chest. But a 12V car battery has hugely more energy in it and can kill you in a number of ways, not the least of which is by electrocution stopping your heart. The shock depletes certain electrolytic chemicals in the heart muscle itself and it can no longer beat in a coordinated manner. This is "bad."

The deal with the MBP is that if you feel this minor current while plugged in, then use the three-prong extension cord on your AC adapter. The case is grounded/earthed through the adapter to the ground/earth pin on the plug, and there should be nothing left to feel. If you still feel it, your outlet is either not properly wired or faulty and needs the immediate attention of a qualified electrician.

[forumhound]

yes, like i said, finding a missing prong in the jangle of power cords/strips/conditioners fixed my tingling mac. Apparently this was however not a problem, all is well with my precious mbp and even the sony TR which must have been tingling for over 4 years (also has metal case) is fine too. thanks again for all this wonderful electrical info. special thanks to poster from India, who must understand exactly what it's like here in Nepal, as there is little difference except in governments. I am glad I did not ground this system to the nearest pipe, which would have shocked all bathers in the building, as we do have a roof tank, which also has a lightning rod and only the gods know what that's grounded too

[Stelex]

Here it is � Vibrating MacBook Pro � Silver Mac

[forumhound]

Originally Posted by Stelex 

Here it is � Vibrating MacBook Pro � Silver Mac

I think apple just made a mistake when it supplied a 2 prong plug to customers. they would have avoided all this confusion by just providing a grounded plug...and saved a few pisa as well.

[ghporter]

Originally Posted by forumhound 

I think apple just made a mistake when it supplied a 2 prong plug to customers. they would have avoided all this confusion by just providing a grounded plug...and saved a few pisa as well.

Every MBP power adapter (in all the markets I know of) comes with a two prong-plug (I've seen it called a "duck bill") and a three-prong plug...on the end of a 2 meter power cord.

[Simon]

Originally Posted by forumhound 

I think apple just made a mistake when it supplied a 2 prong plug to customers. they would have avoided all this confusion by just providing a grounded plug...and saved a few pisa as well.

We would still be having these discussions though. There are more than enough people with faulty or missing ground wiring. I don't think this is something Apple could easily fix.

[Sherman Homan]

If the house wiring is done incorrectly it doesn't matter how many prongs Apple provides. In a house that is correctly wired the two prong duckbill is perfectly adequate.

[forumhound]

I guess that can be argued. It seems like most of the tingling problem that I had is fixed by folks just using 3 prong adapter - or by making sure there is an earth ground in the entire circuit (within office or house). I am not convinced what Sherman says is true...at least it's not true here. Unless i am missing something...for example:
Tingle=house power+grounded voltage regulator+grounded power strip+ungrounded strip+3prong brick
Tingle=house power+grounded voltage regulator+grounded power strip+grounded strip+duckbill brick
NoTingle=house power+grounded voltage regulator+grounded power strip+grounded strip+3prong brick
I don't know, maybe this proves nothing but fixed it for me. If the duckbill had never been included in the package and i had made sure all the internal wiring was grounded in the first place, this thread would not exist.
But I guess there could be other reasons, like defective brick?
Its also odd, I have never seen another pc laptop that came with a two prong plug in the box...

[ghporter]

Your local power utility is responsible for making sure that the neutral leg of your power entry is connected to an earth ground (or at least is in North America). This is a safety issue, since a difference in potential between earth and neutral can cause the possibility of nasty and potentially dangerous shocks. If your house power entry is not up to snuff, there can be a breakdown in the bonding between neutral and earth which allows the neutral leg to drift away from earth and possibly have your whole premise wiring "float" neutral to something that you can feel through the case of an appliance.

Since Apple resides in California, their engineers used certain assumptions about customer power, like the expectation that neutral and ground would be very close in voltage. When the products were altered (like the different plug configuration for other standards worldwide), I don't think they re-thought their expectations of premise wiring.

[finboy]

Originally Posted by analogika 

Note that the tingling you feel on the MacBook Pro has been present on nearly all machines since the very first metal (titanium) Powerbooks, 7 years ago.

It is - according to an Apple service rep I talked to - part of spec, and not a problem. The only solution they suggest is using the grounded extension cord.

My G3 900 iBook (2003) does the same thing. Always has.

[Connie]

Originally Posted by finboy 

My G3 900 iBook (2003) does the same thing. Always has.

Same here, iBook G4 1.2Ghz at the latch. Sometimes it mildly shocked me when I accidently finger over there. Cool features, indeed!