[Elecraft] Antistatic mat without electrical ground

[David Woolley (E.L)]

Apologies for breaking threading.

Paul G4LNA wrote:

 > Just run a wire to a rod outside, it doesn't matter how long the
 > wire is, as you say it's not an RF ground. I wouldn't use the gas
 > pipe for safety reasons.

This advice is dangerous and doesn't even really achieve what one needs 
to achieve.

It's dangerous because, if there is a fault which connects live to any 
exposed metalwork, you have introduced a low resistance path to earth 
into an environment where the the fault was much less dangerous because 
only high resistance return paths existed.

What you are really trying to do make sure that all, even partially, 
conducting surfaces are at the same voltage, including you and the 
soldering iron tip.  Normally you can rely on internal surfaces being 
insulated or connected to mains earth, because that is what modern 
electrical codes require, so it is normally appropriate to connect the 
mat to mains earth.

As far as I know, in the UK, you would have electricity supply refused 
if you had two wire mains sockets (shaver sockets are specially 
isolated), except for environments which are specifically designed to be 
earth free, in which case you would not be allowed to have anything 
connected to earth.

If you only have two wire sockets, or, more generally, if you do not 
know how the mains earth is arranged, you really need to consult a 
competent electrician before doing anything that involves earthing at DC 
to mains frequencies.  You should treat any metal connected to true 
earth, and inside, as though it was at mains voltage, and you should 
treat any wires going to the outside, as being at mains voltage, when 
outside.

My own guess is that you either need to completely rewire to include an 
earth wire and properly earth all relevant appliances and bond other 
conductive surfaces to that earth, or to establish a work area that is a 
body's length from any electrical outlet, or equipment, provide 
conductive flooring, bond all surfaces electrically and use a battery 
powered soldering iron.  (Your electrical codes may be more specific 
about the separation distance.)  I think there are variations on this 
that provide some mains power, but I wouldn't want to suggest anything 
without detailed knowledge of local electrical codes.

In general, if you put in earth rods, they must be connected to the 
mains earth or completely isolated from the electrical system, by 
sufficient distance that it is impossible to touch anything that can 
come into contact to one of them at the same time as anything that can 
come into contact with the other.


WY5Q wrote:
 >
> My house does not have grounded electrical outlets. What is the best
> way to protect against static during assembly of the K3 kit? Ground
> the mat to a ground rod outside? Or to a metal gas pipe (for
> grounding me, not as RF ground!)? There are no water pipes accessible
> my build location.
-- 
David Woolley
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