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I want to do laptop maintenance and looking to ground myself with an anti-static wrist strap.

How, or where, do I ground myself to the laptop? Where can I find a grounding point in order to not make a mistake and spoil something?

random
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Boris_yo
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3 Answers3

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The purpose of grounding is to allow electrons on you to flow to an object so that the voltage difference between two objects is 0. This is so you don't dissipate the voltage directly onto the motherboard and other vital components.

Mike Insch does not understand the concept of ground. A ground is merely a reference point for which other objects voltages are compared to. The electrical earth might actually have a different electrical potential from that of the chassis. This could very well be the case in laptops with only two prong power supplies

A laptop chassis can be a ground, as long as it is on a good conductor. Those plastic chassis won't work. Also, it is really difficult to find an appropriate place to clamp the wrist strap. Also, I have had many laptops power supplies only have TWO PRONGS. There is no connection to the electrical earth.

The laptop should not be worked on while plugged in or with the battery in not because of lack of earthing, but rather because there is current still flowing through the motherboard.

Edw
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    Sometimes one can access fastener screws for e.g. VGA connectors. That might work as chassi ground. – Daniel Andersson Nov 22 '12 at 18:14
  • An anti-static mat might help. You may place the motherboard on the anti-static mat, and connect your wristband to the mat. The mat should have such a low resistance by design, that it will accomplish the same as attaching to the motherboard directly. Of course you would first have to remove the board from the chassis before placing it on the mat. while doing that, you have to be connected to the board itself. But at least after placing it on the mat, you have more freedom to handle the board using a mat. – Static Storm Sep 09 '18 at 16:59
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Theoretically, the entire idea of the strap is so that you & your work are at the same potential. This isn't to protect you from mains voltage [there is some protection in one of these straps, but common sense of disconnecting from live mains is preferred], but to protect the circuitry from any damaging static charge you're carrying. Mains Earth [US: Ground] is as good a leveller as any for this purpose, if everything is connected to the same point.
Your actual issue for a laptop is that the power supply doesn't actually connect the laptop to earth at all, even if the external 'transformer' section has an earth pin to a good mains earth. It may have sufficient leakage from signal ground to mains earth to keep it potentially level, but it's a side-effect rather than an intentional provision.

In theory, this makes it 'not a good solution'. In practise, however, there's a fairly broad tolerance.
To get yourself down to ground potential you can just grab a tap [faucet]. If you don't get a tiny shock you weren't far off equal potential anyway. So long as you don't run around a nylon carpet wearing plastic shoes & a nylon shirt, rubbing a cat on your front on a really dry day, you're unlikely to build up enough charge to cause any issues between doing that & getting back to your laptop.

At that point, you can clip your wrist strap to any convenient metal part of the computer. Leaving the charger connected to the mains but with the switch off might help towards keeping you all at the same potential, even though there's no real path to earth between laptop & wall plug, but you're not going to really get too far from that water pipe ground zero anyway. If you have a desk with metal framing, even that would be enough to connect you & your work to, in absence of a constant real earth.
You'll be fine.

Tetsujin
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You do not want to ground yourself to the laptop. You want to be grounded to earth.

The anti-static wrist strap should have come with an attached wire. The other end of that wire should be connected to an electrical ground. The center screw of the AC wall outlet holding the cover plate is a suitable connection point that is tied to your dwelling's ground (assuming you have 3-prong outlets and the outlet is properly wired and up to code). Make sure you attach to bare metal and not the paint on the screw.

Once you are grounded, you do not want to touch any live circuit. So the equipment should be turned off and unplugged. Ideally, especially with high voltage devices, you should use the hand that has the strap to poke around and the other hand behind your back or in your pocket. The idea is that if you do get shocked, the electrical current only has a path from your hand to the strap, and not across your chest and heart.

sawdust
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    But i heard i can ground to laptop which is plugged in AC outlet while shut down. This is not true? – Boris_yo Aug 11 '11 at 10:56
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    No, you cannot ground to a laptop connected to an AC outlet - the laptop's power-supply is where the connection to the electrical earth stops, there is no electrical earth within the laptop chassis. You should *always* connect your wrist strap directly to an electrical earth and never to the equipment you are working on, regardless of whether it's a laptop, desktop etc. – Mike Insch Aug 11 '11 at 11:23
  • @MikeInsch Thanks Mike. Just to make sure, in case I work with desktop computer, I ground to computer's chassis or power supply? I often have heard about former by the way. – Boris_yo Aug 29 '12 at 14:36
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    @Boris_yo While you can leave the AC cord connected to the power supply and then ground off to the PSU or Chassis, I personally wouldn't recommend doing so - a faulty RCD / RCBO on the supply circuit and / or a faulty Power Supply could cause current to conduct to earth via *you*, and while unlikely it's not worth the risk. If you must ground yourself to the equipment, you can ground to the Chassis only if the PSU is still properly mounted and electrically and mechanically connected to the Chassis, otherwise you must ground to the PSU itself. – Mike Insch Aug 29 '12 at 14:55
  • @MikeInsch So you don't recommend grounding to chassis, PSU or any equipment at all that has faulty supply unit while AC power is connected from mains? Or you generally don't recommend connecting to anything but only from wall socket's ground? – Boris_yo Sep 01 '12 at 11:19
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    The bit about high-voltage devices really doesn't belong here. We're talking about working on a laptop, using a strap to avoid damaging it with *static* electricity. The kind of device where high-voltage might be present (such as a PSU) is not something the amateur should open up anyway; safety considerations aside, it's too easy to destroy the system if you don't know what you're doing. – Isaac Rabinovitch Nov 22 '12 at 18:17
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    As the above poster says: this is not about HV. The goal is to avoid _static_ discharge (ESD) from potentially (ha!) ruining sensitive electrical components. The only thing of concern is for your body to have the same potential as the laptop—nothing else. It is _not_ helpful to ground oneself to earth ground if the laptop itself is not plugged in to an earthed wall socket. So this answer as it stands is wrong for the application in question: you __do__ want to ground yourself to the laptop, to avoid ESD (for HV applications, an ESD wrist strap won't be able to handle the load anyway). – Daniel Andersson Nov 23 '12 at 07:01
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    @sawdust: _"Once you are grounded, you do not want to touch any live circuit."_ Assuming you're using a proper grounding wrist strap + cable, this is not an issue. All such setups have a 1 Mohm resistor in series. Even 500 V can only push half a milliamp through that. This does NOT mean that it is safe to work on powered equipment (there might be some other much lower-impedance path through you to supply ground); it does mean that the ground strap in no way increases the risk of dangerous electric shock. – Jamie Hanrahan Oct 08 '14 at 06:23
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    sawdust and mike-insch tell you explicitly to not connect to the laptop, but connect to Earth itself. As @Daniel-Andersson points out their answer is downright wrong. The laptop itself may have an whole different potential than the Earth, causing the potential form the laptop to flow away though you when you handle it. That was exactly waht you wanted to avoid, as it might damage the components of the laptop. Please also have a look at https://superuser.com/questions/975427/how-to-properly-use-an-antistatic-wrist-strap-when-working-on-a-desktop-pc/1055702#1055702 for a more detailed answer. – Static Storm Sep 09 '18 at 16:56
  • This answer is just so wrong. The strap is not designed to protect you from mains, it's to remove any potential difference between you & the equipment. Technical Earth is merely one way to ensure the potentials are all equal. You could ignore true Earth & still arrive at equilibrium, even with a large DC offset, so long as you don't ever touch true Earth whilst doing it. True earth is merely an easy option; easy to find, easy to connect to, massive enough that nothing is ever going to upset it whilst you're working with it. In essence, inviolable. – Tetsujin Apr 24 '23 at 13:16