Safety Tip #4: Look for the safety listing agency’s emblem on the meter

What are the Standards?

To provide improved protection for users, industry standards organizations have taken steps to clarify the hazards present in electrical supply environments. The American National Standards Institute (ANSI), the Canadian Standards Association (CSA), and the International Electro-Technical Commission (IEC), have created more stringent standards for voltage test equipment used in environments of up to 1000 volts.

ANSI, CSA and IEC define four measurement categories of over-voltage transient impulses. The rule of thumb is that the closer the technician is working to the power source, the greater the danger and the higher the measurement category number. Lower category installations usually have greater impedance, which dampens transients and helps limit the fault current that can feed an arc.

• CAT (Category) IV is associated with the origin of installation. This refers to power lines at the utility connection, but also includes any overhead and underground outside cable runs, since both may be affected by lightning.

• CAT III covers distribution level wiring. This includes 480-volt and 600-volt circuits such as 3-phase bus and feeder circuits, motor control centers, load centers and distribution panels. Permanently installed loads are also classed as CAT III. CAT III includes large loads that can generate their own transients. At this level, the trend to using higher voltage levels in modern buildings has changed the picture and increased the potential hazards.

• CAT II covers the receptacle circuit level and plug-in loads.

• CAT I refers to protected electronic circuits.

Independent testing labs help ensure safety compliance You want your tools and equipment to help you work safely. But how do you know that a tool designed to meet a safety standard will actually deliver the performance you are paying for? Unfortunately it’s not enough to just look on the box. The IEC (International Electrotechnical Commission) develops and proposes standards, but it is not responsible for enforcing the standards. Wording like “Designed to meet specification...” may not mean a test tool actually performs up to spec. Designer’s plans are never a substitute for an actual independent test.

That’s why independent testing is so important. To be confident, check the product for the symbol and listing number of Underwriters Laboratories (UL), the Canadian Standards Association (CSA), TÜV or another recognized testing organization. Those symbols can only be used if the product successfully completed testing to the agency’s standard, which is based on national/ international standards. That is the closest you can come to ensuring that the test tool you choose was actually tested for safety.

What does the CE symbol indicate?

A product is marked CE (Conformité Européenne) to show it conforms to health, safety, environment and consumer protection requirements established by the European Commission. Products from outside the European Union cannot be sold there unless they comply with applicable directives. But manufacturers are permitted to self-certify that they have met the standards, issue their own Declaration of Conformity, and mark the product “CE.” The CE mark is not, therefore, a guarantee of independent testing.

Don’t be confused by “Listed” vs. “Designed to” in your test tools. IEC sets the standards but does not test or inspect for compliance. So a manufacturer can claim to “design to” a standard with no independent verification. To be UL-Listed, CSA or TUV-Certified, a manufacturer must employ the listing agency to TEST the product’s compliance with the standard. Look for the listing agency’s emblem on the meter.