Grounding yourself when the outlets are not grounded

[rtarbell]

I am going to be moving to a small house pretty soon (dirt cheap rent, heat and electricity included!!). In terms of my DIY efforts, none of the outlets in my room have a ground (they are all two pronged plugs), which gives me a problem:

I like to take no chances when working, so I always wear a grounded wrist-strap when soldering and assembling.

I used to ground myself to the back of my computer case, but if the computer itself is not grounded (because of no third prong on the outlet that it will be plugged in to), then I think it would defeat the point.

For things in the room I might use to ground myself for ESD, I see a copper heat pipe for the base board heater, another copper pipe that goes to the bathroom in the next room, and the shield on the coaxial cable for cable television. Any suggestions as to what would be wise to use? The application is NOT for an actual safety ground for electrical equipment - just for an ESD ground.

Thank you!

[theAnonymous1]

I think any of the copper piping you mentioned will be fine. The coax should be fine too; mine is grounded.

You will probably have to worry more about NWD now than ESD.

NWD = Neighborly Weapon Discharge.

[mikje]

If I'm not mistaken, when working on a computer, you want to be at the same potential as the computer. With that in mind, for ESD protection, grounding yourself to the computer will do the job. Use an antistatic work surface too, and you should be in good shape.

Copper pipes work for earth ground, as long as you use the cold water pipe.

If I'm in error, somebody please let us know.

Mike

[martin clark]

Whichever route you choose, do use a strap that incorporates a resistor!

Most commercial 'antistatic' wrist-straps connect to the ground reference (here in teh UK, to the Mains earth via a special 3-prong plug) via a 1mega-ohm resistor. This is quite important - it drains off static gradually - which limits the possible rate of discharge - and it also prevents you getting shocked if you get forgetful and work on something referenced to a different voltage than mains 'earth. For example, your water pipe might be at a different potential w.r.t the mains earth/neutral from the local socket your soldering iron is plugged/referenced to...

So DO NOT wrap a bit of copper wire araound your wrist and think that's good enough. It may not safe...

[Eva]

Earthing yourself directly is a very dangerous practice, it calls for shocks and trouble, unless you do so through a 1 Mohm resistor (or a value high enough to limit current to non dangerous levels) with suitable voltage rating. ESD is handled that way too.

Don't expect water pipes or cable shields to be at earth potential.

[Geek]

In terms of my DIY efforts, none of the outlets in my room have a ground (they are all two pronged plugs)...

I'd call an electrician. I don't think 2-prong outlets are legal anywhere in North America, regardless of "heritage" value the house may have.

Cheers!

[HK26147]

Unfortunately old US houses that were wired using the 1st generation of wiring ( during the 1940's ) were implemented with 2 prong sockets ( with only the work box grounded ). And there are still old installations with aluminum residential wiring.

The need to establish electrical ground to work is NOT the same as the earth grounding for the power system.
A ground strap prevents discharge of static that can punch through semiconductor gates.
As mikje said, the strap to the chassis keeps the same potential so static doesn't discharge into the circuit.

I would never tie myself into any part of the mains circuit.
A line man wears heavy rubber insulated gloves and boots and would never attach themselves to a path to ground.
Electricity follows the path of least resistance. If the normal neutral path to ground is not firmly established. You can become the path to ground.
The infamous story of grabbing a mic stand attached to a system where someone has lifted the power ground: The unfortunate individual get a huge shock - sometimes lethal as electricity has found an lower resistance path to ground.
Don't lift power grounds, or clip ground pins. By the way if an OSHA inspector finds clipped cords on a site, work can be shut down.
I don't solder on an energized circuit - they are totally disconnected from the power circuit and discharged if necessary.

[theAnonymous1]

I honestly don't think grounding is even necessary unless the place has forced air heating. I live in the same area as the OP and I never bother grounding myself, even in the winter months.

I've been doing PC stuff for ~9 years and electronics for ~4 years and have never had a problem with ESD.

All the places I have lived in the past 10 years had radiant heat however.

[HK26147]

I must confess theAnonymous1 that I haven't had to use an ESD either - Even in the 70's, when I soldered up microprocessors (programed in HEX ).
I haven't lost a patient yet to static ( touch chassis )
Avoid low humidity/dry air, and nylon carpet etc.

[mikje]

Static can have a cumulative effect. A static discharge can be dangerous to some components even if you can't feel it. In this case, it would be wise to err on the side of caution.