Desco 19245 User manual

TB-3055 Page 1 of 4 © 2012 DESCO INDUSTRIES, INC.
Employee Owned
Low Resistance Tester
Operation and Maintenance
Description
Desco’s Low Resistance Tester is designed to measures
resistance of grounding paths of banana jacks and other
equipment. Selectable Test Ranges: <1 ohm, <2 ohms and
<20 ohms allow the operator to test grounding conductors
per ANSI/ESD S6.1 – Grounding and ESD TR20.20. The
Tester is equipped with pass/fail (go/no go) audio and
visual indicators that activate to confirm that the grounding
conductor being tested meets the test range. The low
battery indicator lets the operator know when battery needs
to be replaced.
ESD Handbook ESD TR20.20 section 5.5.2.2 Electrical
Hand Tools
“All electrical tools and equipment used to process ESD
sensitive devices require the three prong, grounded-type AC
plug. The metal portions of the tool that touch the device
should have a low resistance (<2 ohms) to the equipment
ground terminal on the plug. In some cases, the user
may wish to verify that the metal portions of the tool have
acceptable voltage levels and leakage current. The tester
defined in ESD STM13.1 provides a means of checking
soldering iron tips while being used. Although the document
was written to make measurements on soldering and
desoldering equipment, the measurement techniques can be
used for other electrical hand tools. The working part of AC
powered tools should be capable of providing a conductive
path to ground. New powered hand tools such as soldering
irons typically should have a tip to ground resistance of less
than 1.0 ohm.
NOTE: This resistance may increase with use but should be
less than 20.0 ohms for verification purposes.”
December 2012
Figure 1. Desco 19245 Low Resistance Tester
ANSI/ESD S6.1 – Grounding
“6.4.1 The resistance of the conductor from the groundable
point ground of any ESD technical element (e.g. worksurface,
floor, chair, wrist strap, etc.) to the common point ground or
common connection point shall not be greater than 1 ohm.
Where a resistor is used in the grounding conductor, the total
resistance shall include the value of the resistor.
6.4.2 The resistance of the conductor from the common point
ground to the AC equipment ground shall not be greater than
1 ohm.”
Packaging
1 Low Resistance Tester
1 Threaded Banana Plug
1 Threaded Needle Point
1 Alligator Clip
1 Banana Jack Outlet Adapter
1 Certificate of Calibration
Features and Components
TECHNICAL BULLETIN TB-3055
A. Selectable Test Ranges: Select the appropriate range
for required test <1 OHM, <2 OHMs, and <20 OHMs.
B. Test Button: Press and hold button to activate the tester.
C. Threaded Banana Plug/Needle Point: Standard Kit
includes a banana plug and needle point adaptor.
D. Audio and Visual Test Indicators: LED and buzzer Pass
result.
Figure 2. Low Resistance Tester features and
components
A B C D E G
F
Made in the
United States of America

TB-3055 Page 2 of 4 © 2012 DESCO INDUSTRIES, INC.
Employee Owned
E. Low Battery LED: LED illuminates when the battery
needs to be replaced.
F. 6 Foot Coiled Cord: Insulation black color PVC
G. Banana Plug: Industrial Standard .175" (4.4 mm) Banana
Plug, fits banana jack ≥ .157".
Operation
USING THE TESTER
1. Use the slide switch to select a test range.
2. Connect the coil cord banana plug end to known ground.
Use adapters where needed. NOTE: The Desco Low
Resistance Tester may be used with an outlet polarity
checker such as the Desco 19219 to determine a known
ground.
3. Connect or touch the tester end to a banana jack or
other equipment that is being tested for resistance to
ground.
4. Press and hold the test button.
5. An audio and visual indication will activate for a PASS
condition.
6. A FAIL condition is indicated when the buzzer does not
sound and the PASS does not illuminate.
Figure 3. Testing ground points with the 19245 tester
Example of Test Range Uses
<1 OHM Range
- ESD Technical element Grounding Conductors:
Banana Jacks, Grounding Blocks, Mat Ground Cords
ANSI/ESD S6.1 Grounding, sections 6.4 Technical
Elements, 6.4.1, 6.4.2 and 6.4.3
- New AC Powered Hand Tools
ESD Handbook ESD TR20.20 section 5.5.2.2 Electrical
Hand Tools
<2 OHM
- Soldering Irons
ESD Handbook ESD TR20.20 section 5.5.2.2 Electrical
Hand Tools
- Other AC Powered Hand Tools
ESD Handbook ESD TR20.20 section 5.5.2.2 Electrical
Hand Tools
<20 OHM
- Soldering iron verification
ESD Handbook ESD TR20.20 section 5.5.2.2 Electrical
Hand Tools
- Auxiliary grounds (ground rods)
ANSI/ESD S20.20*
* ANSI/ESD S20.20 requires <25 ohms from the Auxiliary
Ground to the Equipment Grounding Conductor. Desco’s
Low Resistance Tester only tests to <20 ohms. In cases
of a no pass result with the Low Resistance Tester when
testing an Auxiliary Ground, an Ohm meter should used to
determine the actual resistance from the Auxiliary Ground to
the Equipment Grounding Conductor
Figure 4. Testing a soldering iron with the 19245 tester
Figure 5. Testing auxiliary ground with the 19245 tester
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
TestEquipmentDepot.com

TB-3055 Page 3 of 4 © 2012 DESCO INDUSTRIES, INC.
Employee Owned
5. Re-assemble the tester.
Specifications
Output Voltage: 2.5 volts DC @ 10mA
Dimensions: 4.75" x 1.75" x .75" (12cm x 4.5cm x 2cm)
Operating Temperature: 0° - 40°C
Calibration
The Low Resistance Tester is calibrated to standards
traceable to NIST. Frequency of recalibratrion should be
based on the critical nature of those ESD sensitive items
handled and the risk of failure for the ESD protective
equipment and materials. In general, we recommend that
calibration be performed annually.
Calibration is performed by placing various resistors between
the probe tip and the lead wire.
1. Attach the alligator clip to the lead wire.
2. Set the Low Resistance Tester to the 1 ohm test setting.
3. Attach the lead of a 1 ohm resistor to the alligator clip.
4. Firmly place the tester’s probe tip on the opposite resistor
lead.
5. Press and hold the test button. The PASS LED should
illuminate.
6. Repeat the procedure with a 1.2 ohm resistor. The PASS
LED should not illuminate.
7. Repeat this process with the ranges listed in the table
below. If the unit fails calibration, check and replace the
battery.
Test Range Setting PASS FAIL
1 ohm 0 to 1 ohm ≥ 1.2 ohms
2 ohms 0 to 2 ohms ≥ 2.2 ohms
20 ohms 0 to 20 ohms ≥ 22 ohms
Maintenance
BATTERY REPLACEMENT
1. Properly ground yourself using a wrist strap.
2. Remove the 2 screws located at the back of the tester.
Figure 6. Locating the enclosure screws
Figure 7. Removing the back cover
3. Remove and turn over the circuit board.
4. Locate and replace the battery (3 Volt; Model CR2032).
First, place
battery under
prongs
Next, press here to snap
battery in place
Figure 8. Replacing the battery

TB-3055 Page 4 of 4 © 2012 DESCO INDUSTRIES, INC.
Employee Owned
Limited Warranty
Desco expressly warrants that for a period of one (1) year from the date of purchase, Desco Low Resistance Testers will be free of
defects in material (parts) and workmanship (labor). Within the warranty period, a credit for purchase of replacement Desco products,
or, at Desco’s option, the product will be repaired or replaced free of charge. If product credit is issued, the amount will be calculated by
multiplying the unused portion of the expected one year life times the original unit purchase price. Call Customer Service at 909-627-
8178 (Chino, CA) or 781-821-8370 (Canton, MA) for Return Material Authorization (RMA) and proper shipping instructions and address.
Include a copy of your original packing slip, invoice, or other proof of date of purchase. Any unit under warranty should be shipped
prepaid to the Desco factory. Warranty replacements will take approximately two weeks.
If your unit is out of warranty, Desco will quote repair charges necessary to bring your unit up to factory standards. Call Customer Service
at 909-627-8178 (Chino, CA) or 781-821-8370 (Canton, MA) for a Return Material Authorization (RMA) and proper shipping instructions
and address.
Warranty Exclusions
THE FOREGOING EXPRESS WARRANTY IS MADE IN LIEU OF ALL OTHER PRODUCT WARRANTIES, EXPRESSED AND IMPLIED,
INCLUDING MERCHANTABILITY AND FITNESS FOR A PARTICULAR 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 consequent, 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.
99 Washington Street Melrose,
MA 02176Phone
781-665-1400 Toll Free
1-800-517-8431
Visit us at www.TestEquipmentDepot.com