Would this do for an anti static measure?

  edennorman 14:39 31 Jul 2005

Lacking a "proper" anti static wrist strap...and needing to work on my daughters pc now....If I took a length of single core cable...stripped back enough to wrap around my wrist and connected it to the earth... (not live :)....of a domestic plug and plugged it in.

Would that suffice as a bootstrap anti static measure?

Thank you.


  Pooke 14:40 31 Jul 2005

just touch the radiator or the outside of the pc case.

  octal 15:26 31 Jul 2005

Never, ever, plug anything into the mains when working on any appliance, its just plain dangerous.

As Pooke says, work on the computer near a radiator and just touch it prior to working on the computer. This will dissipate any static which will take time to build up again.

You don't need a wrist strap. Virtually all printed circuit boards are buffered against static once all the components are populated on the board anyway.

  octal 15:30 31 Jul 2005

Incidentally, you can get wrist straps that have a dummy plug that goes into the mains plug, but they either have a high resistance lead to the wrist strap or they have a high resistance resistor Incorporated in the plug, either way you still don't need them for what you are doing there.

  Arnie 16:31 31 Jul 2005

It is quite safe to have the computer connected to the mains socket if you feel happier about earthing the PC in this way.

Take a standard computer UK power lead and remove the fuse from the plug. Plug into the wall socket and the power input of the PC.

Now if the wall switch is accidentally activated whilst you are working on the computer you will be safe.

The EARTH will still be connected with the switch, on or off.

However, if you just keep touching the metalwork on the chassis of the PC, you don’t need to use a power lead at all.

Antistatic protection as above, is about equalising potential differences (PDs) between your body and your equipment, not necessarily about everything being at zero potential.

When CMOS chips are zapped, this is because the static built up in your body, possibly after stroking the cat or walking across the carpet, is trying to equalise itself by flowing through the parts you have just touched. These parts may be at zero potential, hence the zapped devices.

If the parts were at the same potential as your body, even say thousands of volts, nothing would happen.

You could touch the 240 volt line supply if you were standing on a metal plate of the same equal potential and on the same supply phase. It is all about the potential difference between you and the system.

BTW don’t try this last experiment it, is simply an analogy.

  woodchip 16:39 31 Jul 2005

Is just plain stupid to suggest, for anyone to connect to a mains plug by means of length of wire, earth or otherwise. and shove it in a 240 volts socket. how do you know that the socket as bee connected correctly. Or for that matter that the supply is safe, at all

  octal 17:24 31 Jul 2005

Arnie, I'm sorry you are wrong to say you should plug anything into the mains, fuse or no fuse, you are putting peoples lives at risk to suggest otherwise.

If you want to go down that route of plugging anything in the mains you use the proper tools for the job click here

  Forum Editor 17:50 31 Jul 2005

The average computer user is not a qualified electrician or electrical engineer, and it's unwise to suggest to such people that they should adapt or alter an electrical plug, or the flex connected to it.

In theory it may be safe, but house wiring isn't always in first-class order, and for that reason our advice is that you do not attempt to make your own anti-static devices, or to work inside the case of a computer that is connected to the mains. Wear a proper anti-static wrist-strap, or touch a radiator before touching the components inside your computer.

I've worked on and built computers for many years. During the whole of that time I have never once worn an anti-static device of any kind, and have never once lost a component from static discharge. Perhaps I've been lucky - I always make a point of touching radiators, and perhaps that does the trick.

  Arnie 17:53 31 Jul 2005

Yes, my apologies.
Unfortunately I always tend to assume that other people have the facilities to check that their mains wiring supply is correctly wired and is fitted with an RCD.

Even so, God help anyone who's line is connected to the earth pin on one of their 13A sockets, without an RCD fitted.

This could cause the whole casing of their computer to become live without any protection.

I did go on to say. "However, if you just keep touching the metalwork on the chassis of the PC, you don’t need to use a power lead at all".
But I do understand your worries and again apologise unreservedly.

  Diemmess 17:58 31 Jul 2005

The precaution is to avoid a charge of static electricity being discharged through a very sensitive semi-conductor device.

We are not talking of measurable current here, just lots of volts built up by passing different substances over one another, eg nylon shirt cuffs over glass or a different plastic. A carpet of man-made fibre and dry shoes.

The weather is so humid at the moment that a static charge is unlikely to build by accident, but in dry frosty weather even a comb through your own hair makes the hair stand on end and builds a charge. Have you heard the crackles when taking off an acrylic pullover shirt in those conditions as micro lightning occurs?

So, pull the mains plug and provided you make sure one hand touches the case frequently there is little risk of static damage to anything you do inside a computer because the case, its contents and you are all at the same potential.

A wrist strap is a largely unnecessary luxury, but its main safety feature is that it forms a high resistance leakage path, so that should you accidentally connect yourself to the mains, the amount of current is so limited by this resistance and is so small as to be not even noticed. This is not something to bank on, but could prevent a shock, where a simple strand of copper would ensure that an unwise connection could be lethal

  Arnie 18:00 31 Jul 2005

I can add the FE to woodchip & octal.

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

AMD Radeon Adrenalin release date, new features, compatible graphics cards

Inside the iMac Pro - Apple's most powerful Mac yet

iMac Pro release date, UK price & specs

Comment nettoyer Windows et optimiser son PC gratuitement ?