Introduction To Product Safety Testing - Extech Instruments 7470 Operation Manual

1.4.5. Device Under Test
When testing with DC, always discharge the capacitance of the item under test and
anything the high voltage may have contacted–such as test fixtures–before handling it
or disconnecting the test leads.
HOT STICK probes can be used to discharge any capacitance in the device under test
as a further safety precaution. A hot stick is a non-conducting rod about two feet long
with a metal probe at the end that is connected to a wire. To discharge the device
under test, two hot sticks are required. First, connect both probe wires to a good earth
ground. Then touch one probe tip to the same place that the return lead was
connected. While holding the first probe in place, touch the second probe tip to the
same place where the high voltage lead was connected.
1.4.6. Key Safety Points to Remember
 Keep unqualified and unauthorized personnel away from the test area.
 Arrange the test station in a safe and orderly manner.
 Never touch the product or connections during a test.
 In case of any problem, turn off the high voltage first.
 Properly discharge any item tested with DC before touching connections.

1.5. Introduction to Product Safety Testing

1.5.1. The Importance of Safety Testing
Product Safety Tests are specified during the design and development stages of a
product as well as in the production of the products to insure that it meets basic safety
requirements. These tests are designed to verify the safety of the electrical products
in that they do not jeopardize the safety of the people, domestic animals, and property
of anyone who may come in contact with these products. In an era of soaring liability
costs, original manufacturers of electrical and electronic products must make sure
every item is as safe as possible. All products must be designed and built to prevent
electric shock, even when users abuse the equipment or by-pass built in safety
features.
To meet recognized safety standards, one common test is the "dielectric
voltage-withstand test". Safety agencies which require compliance safety testing at
both the initial product design stage and for routine production line testing include:
Underwriters Laboratories, Inc. (UL), the Canadian Standards Association (CSA), the
International Electrotechnical Commission (IEC), the British Standards Institution (BSI),
8
Never touch the Device Under Test (DUT) or anything connected
to it while high voltage is being applied by the hipot.