Siemens SIMATIC S5 Manual page 5

One can never be sure whether the human body or the material and tools which one is using
are not electrostatically charged.
Small charges of 100 V are very common; these can, however, very quickly rise up to 35000 V.
of static charge:
- Wafking on a carpet
-
Walking on a PVC flooring
-
Sitting on a cushioned chair
- Plastic desoldenng unit
- Plastic coffee cup
-
Plastic bags
-
Books, etc. with a plastic binding
3 important Protective Measures against Static Charge
. Most plastic materials are highly susceptible to static charge and must therefore be kept as
far away as possible from ESDS.
. Personnel who handle ESDS, the work table and the packing must all be carefully grounded.
4 Handling of ESD Modules
One basic rule to be obsewed is that electronic modules should be touched by hand
only if this is necessary for any work required to be done on them. Do not touch the
component pins or the conductors.
Touch components only if
- the person is grounded at all times by means of a wrist strap
or
- the person is wearing special anti-static shoes or shoes with a grounding strip.
Before touching an electronic module, the person concerned must ensure that (s)he is
not carrying any static charge. The simplest way is to touch a conductive, grounded
item of equipment (e.g. a blank metallic cabinet p-, water pipe, etc.) before
the module.
Modules should not be brought into contact with insulating materials or materials which
take up a static charge, e.g. plastic foil, insulating table tops, synthetic clothing, etc.
Modules should only be placed on conductive surfaces (table with anti-static table top,
conductive foam material, anti-static plastic bag, anti-static transport container).
Modules should not be placed in the vicinity of monitors, TV
from screen > 10 cm).
v
up to 35000
v
up to 12000
18000 V
to 8000 V
v
up to 5000
v
up to 5000
to 8000 V
sets (minimum distance
touching