Generating Static; Preventing Electrostatic Damage To Equipment; Personal Grounding Methods And Equipment - HP Xw8400 - Workstation - 4 GB RAM Technical Reference Manual

Generating static

The following table shows that Different activities generate different amounts of static electricity. Static
electricity increases as humidity decreases.
Table 4-1 Static electricity
Walking across carpet
Walking across vinyl floor
Motions of bench worker
Removing bubble pack from PCB
Packing PCBs in foam-lined box
CAUTION:

Preventing electrostatic damage to equipment

Many electronic components are sensitive to ESD. Circuitry design and structure determine the degree
of sensitivity. The following packaging and grounding precautions are necessary to prevent damage to
electric components and accessories.
●
Transport products in static-safe containers, such as tubes, bags, or boxes, to avoid hand contact.
●
Protect all electrostatic parts and assemblies with conductive or approved containers or packaging.
●
Keep electrostatic-sensitive parts in their containers until they arrive at static-free stations.
●
Place items on a grounded surface before removing them from their containers.
●
When handling or touching a sensitive component or assembly, ground yourself by touching the
chassis.
● Avoid contact with pins, leads, or circuitry.
●
Place reusable electrostatic-sensitive parts from assemblies in protective packaging or conductive
foam.

Personal grounding methods and equipment

Use the following equipment to prevent static electricity damage to equipment:
●
Wrist straps are flexible straps with a maximum of one megohm ± 10% resistance in the ground
cords. To provide a proper ground, wear the strap against bare skin. The ground cord must be
connected and fit snugly into the banana plug connector on the grounding mat or workstation.
●
Heel straps, toe straps, and boot straps can be used at standing workstations and are compatible
with most types of shoes or boots. On conductive floors or dissipative floor mats, use them on both
feet with a maximum of one-megohm ± 10% resistance between the operator and ground.
Table 4-2 Static shielding protection levels
Method
Antistatic plastic
ENWW
Event
700 volts can degrade a product.
Voltage
1,500
Relative Humidity
5% 4%
7,500 V 15,000 V
3,000 V 5,000 V
400 V 800 V
7,000 V 20,000 V
5,000 V 11,000 V
1%
35,000 V
12,000 V
6,000 V
26,500 V
21,000 V
Service considerations 47