Safety Tip #2: Don’t risk CAT IV areas without the right leads

What’s the difference in test leads?

Not all test leads are created equal. It’s very common to accumulate test leads over the years and mix them up with the newer, more robust leads available today. Test leads, just like the testers themselves, have been upgraded to meet the new safety standards established for today’s electrical environments. These standards require that the insulation between the test lead conductor and your fingers have the minimum distance to stand off the hazards that exist in the environment in which you are working. There should also be a finger guard on the outside of the probe that establishes the proper distance between your fingers and the exposed metal parts of the probe. These distances and insulating ratings have been predetermined for each installation category and voltage rating.

What’s the difference in test leads?

Not all test leads are created equal. It’s very common to accumulate test leads over the years and mix them up with the newer, more robust leads available today. Test leads, just like the testers themselves, have been upgraded to meet the new safety standards established for today’s electrical environments. These standards require that the insulation between the test lead conductor and your fingers have the minimum distance to stand off the hazards that exist in the environment in which you are working. There should also be a finger guard on the outside of the probe that establishes the proper distance between your fingers and the exposed metal parts of the probe. These distances and insulating ratings have been predetermined for each installation category and voltage rating.

Another characteristic to watch for is the amount of current test leads can safely handle. In the previous example, the Fluke 170 and 180 Series products are fused to a maximum current of 10 A. When measuring current using test leads with a current rating less than 10 A could cause the test leads to become overheated. This in turn could cause the insulation to melt and compromise the safety rating of the leads. Again, discard all leads that have discoloration or appear to have melted insulation and replace them with new ones.

Category IV ratings

Recently the International Electrotechnical Commission (IEC), an organization that develops safety standards, defined the standards for Category IV environments. This environment includes overhead power lines, underground power lines, and service entrance power. These are environments where electricians make measurements every day. In order for you to make measurements in these environments safely, Fluke has upgraded most of its test lead products to meet the new CAT IV standards. If you find yourself making measurements in these areas and have an older set of leads, you might want to consider replacing them with leads that are clearly marked as rated for CAT IV.