Desco TB-2005 Service Manual

TB-2005 December 2008 Page 1 of 2

Wrist S trap s
Grounding, Testing and Maintenance

Location of Proper Ground Point

Wrist straps, work surfaces, and floor mats
which are to be grounded for protection
against electrostatic discharge (ESD)
should be grounded to a common point.
The common point should be connected to
the “green wire” equipment ground.

Figure 1. Common point ground for each
workstation

This may be accomplished in a variety of
ways utilizing common point ground
blocks, ground buses, or connecting
directly to the nearest utility “green wire”
ground point. In a properly wired building,
the nearest reliable ground point will be
the center screw of the standard 110VAC
outlet.

Figure 2. “Green wire” equipment ground

Each individual workstation must be
individually grounded to the ground bus or
“green wire” equipment ground. Do not

wire work surfaces or other ESD
devices in series or “daisy chain” them.

This can create unknown resistance and
unacceptable grounds.

For a more detailed discussion of ESD
grounding see Desco technical bulletin
TB-2007. For instructions on grounding
Desco workstation mats see technical
bulletin TB-2000.

Test The Ground Before You
Use It And Periodically
Thereafter

Do not assume that any AC electrical
outlet is properly wired. Even if it was
originally wired correctly it can become

ungrounded due to corrosion and wear.

Test the ground you intend to use
before you hook up. We suggest using

Desco’s item 98130 AC Outlet Analyzer
and Wrist Strap Tester.

A Banana Jack Is Recommended

Almost all wrist strap manufacturers
terminate wrist ground cords with banana
plugs. This is because the banana plug
and jack have proven to be a fast and
reliable way to attach to ground. If you
must use another method such as snaps
or alligator clips, due to your particular
environment, be sure to test the
connections often.

Note: Many wrist strap users clip the wrist
cord to the edge of an ESD protective mat.
This process is not recommended as it
can increase the total system resistance to
ground to over the 35 megohm limit
recommended in ESD S 20.20. (ESD
Handbook TR20.20 section 5.3.2.2.2 Wrist
Strap Ground Cord)

Figure 3. Desco’s 09740/09741 dual
bench mount and 09835/09836 quad
common point ground cord are two easy
ways to provide multiple banana jacks at
any workstation.

Compliance Verification of the
Ground System

Set up a schedule to be sure that all ESD
grounds are inspected and tested
periodically, every six months for example.

Testing the Wrist Strap

The best test of the wrist strap system is
while it is worn. This includes all three
components: the wrist band, the ground
cord (including resistor), and the interface
with the wearer’s skin.

Desco has several testers available for
this purpose. For more information ask for
specification drawings or operating
instructions by item number.

09740

09835/09836

Figure 4. Wrist strap testers

If you obtain an open or bad reading from
the tester you should stop work and test
the wrist band and cord individually to find
out which item has failed. Replace the bad
component and test the system again.
Obtain a “Pass” reading before beginning
work.

Cleaning

For proper operation, the wrist strap,
especially the wrist band strip, must be
kept clean. All wrist bands should be
cleaned with a mild detergent on a periodic
basis. Be sure that metallic expansion wrist
bands are thoroughly dried to prevent
corrosion.

Woolite™ works well. Liquid detergents are
better than dry in that there is less caking
and frictional wear. Launder elastic wrist
band strips in cool or warm water, tumble
dry with low heat or hang dry. This works
well if using a standard house machine on
gentle cycle. Industrial machines are fine if
"Pony" (typically under 200 pound loads)
machines are used. It is not recommended
to launder .. in heavy industrial laundry
machines as it will lead to premature wear.
Should be tumbled dry using low heat. DO
NOT BLEACH.

Wrist Strap silver fibers are sensitive to
heat and should not be exposed to
laundering heat in excess of 120°F. Use
only non-ionic softeners and detergents
when laundering."

BENCH MAT

WRIST STRAP
WITH COIL CORD

COMMON POINT
GROUND #09826

FLOOR MAT

FLOOR MAT
GROUND #09814

GREEN

WIRE

EQUIPMENT

GROUND

WARNING!

DO NOT

DAISY CHAIN

THE WRIST STRAP!

19208

19350

19250

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: Desco.com

TECHNICAL BULLETIN TB-2005

Made in America

© 2008 DESCO INDUSTRIES INC.

Employee Owned

NO

Elastic Adjustable Wristbands

The elastic adjustable band is designed to
be adjusted to the proper size to fit each
individual wearer. After adjustment it can
be used as a fixed size band. It is only
necessary to adjust the size once.

1. Place the wristband on the wrist.

2. Open the clasp by pulling upward on
the “tail” of material that extends out from
the clasp.

3. Tighten or loosen the elastic material
through the clasp until the wristband fits
snugly but comfortably.

4. We recommend that you close the
clasp and wear the band with the excess
tail extended for a day to be sure the
adjustment is snug, comfortable, and has
the proper electrical contact with the skin
before cutting.

5. Test the wrist strap system to be sure
of proper electrical resistance and skin
contact. Use the procedure described
under “testing”.

6. When you are ready to cut off
excess material, mark with a pencil where
excess material is to be trimmed.

7. Remove band from wrist. Open
clasp. Cut off excess material about 1/4"
short of pencil mark so that the end of
material is concealed by the cap. This will
eliminate the possiblity of exposed frayed
ends.

8. Close clasp and use as a fixed elastic
wristband.

Replacement of Elastic Material

For use with 09028, 09069, 09070, and
91020 only. When the elastic material

becomes worn, it can be easily replaced.
Order item number 09029 from Desco for
a replacement strip. To replace the fabric,

wearer to cinch the band for a secure fit.
The band will adjust to fit any size wrist.
Contact with the wearer is established
through a conductive teflon tab sewn to the
inside of the band.

1. Attach wrist
strap on wrist
so that the
black
conductive
band makes
contact with skin.

2. Pull strap through D-ring and
cinch the band for a snug fit.

3. Test the wrist strap system to be sure of
proper electrical resistance and skin
contact. Use the procedure described
under "Testing The Wrist Strap" on page 1.

TB-2005 Page 2 of 2

Limited Warranty

Desco expressly warrants that for a period of one (1) year from
the date of purchase, Desco wrist strap components will be
free of defects in material (parts) and workmanship (labor).
Within the warranty period, the product will be tested, repaired,
or replaced at Desco’s option, free of charge. Call our
Customer Service Department at 909-627-8178 (Chino, CA) or
781-821-8370 (Canton, MA) for a Return Material Authorization
(RMA) and proper shipping instructions and address. Include a
copy of your original packing slip, invoice, or other proof of
purchase date. Any unit under warranty should be shipped
prepaid to the Desco factory. Warranty repairs will take
approximately two weeks.

If your unit is out of warranty, call Customer Service at 909­627-8178 (Chino, CA) or 781-821-8370 (Canton, MA) for a
Return Material Authorization (RMA) and proper shipping
instructions and address. Ship your unit freight prepaid. Desco
will quote repair charges necessary to bring your unit up to
factory standards.

Warranty Exclusions

THE FOREGOING EXPRESS WARRANTY IS MADE IN LIEU
OF ALL OTHER PRODUCT WARRANTIES, EXPRESSED
AND IMPLIED, INCLUDING MERCHANT- ABILITY AND
FITNESS FOR APARTICULAR PURPOSE WHICH ARE
SPECIFICALLY DISCLAIMED. The express warranty will not
apply to defects or damage due to accidents, neglect, misuse,
alterations, operator error, or failure to properly maintain, clean
or repair products.

Limit of Liability

In no event will Desco or any seller be responsible or liable for
any injury, loss or damage, direct or consequential, arising out
of the use of or the inability to use the product. Before using,
users shall determine the suitability of the product for their
intended use, and users assume all risk and liability
whatsoever in connection therewith.

Size Adjustment of Wristbands

simply open the clasp as described under
“Adjustment”. Remove the fabric from the
clasp. Note that the second end of the
material is secured to the clasp by a
smaller camlock. Open the small camlock
(A small screwdriver is helpful.) Remove
the fabric and replace it with the 09029. Be
sure no material extends to the end of the
lever arm of the small camlock. This will
cause the clasp to close improperly and
not hold firmly.

Metal Expansion Wristbands

1. Insert the link end of the wristband into
the slotted opening on the cap. Insert it at
a downward angle to allow the links to
slide inside the channel in the backplate.

2. Change the size of the band by sliding
the links in or out of the stainless steel
backplate. For extra small users you can
cut off excess links with cutters.

3. Lock the links into place by pulling
down on the band, seating the band
securely over the lip on the edge of the
backplate.

4. Test the wrist strap system to be sure of
proper electrical resistance and skin
contact. Use the procedure described
under “Testing” section on reverse side.

Hook and Loop Wrist Strap

This wristband consists of a hook and loop
band with a D-ring buckle, a conductive
strip for static charge dissipation, and a
4mm snap stud. The D-ring enables the

DESCO WEST - 3651 Walnut Avenue, Chino, CA 91710 • [phone] • Fax [phone]

DESCO EAST - One Colgate Way, Canton, MA 02021-1407 • [phone] • Fax [phone] • Web Site: Desco.com

© 2008 DESCO INDUSTRIES INC.

Employee Owned

Note: Desco wrist straps and coil cords are UL
Listed for safety. However, this product is not
recommended for use on equipment with
operating voltage exceeding 250 VAC.

CAUTION: The ESD Series is for electrostatic
control. It will not reduce or increase your risk of
receiving electric shock when using or working
on electrical equipment. Follow the same
precautions you would use without wrist straps,
including:

• Make certain that equipment having a
grounding type plug is properly grounded.

• Make certain that you are not in contact with
grounded objects other than through the ESD
Series.