Electrical Test Instruments are discussed very briefly and often shrugged off in safety articles. The incomplete and/or incorrect knowledge & awareness regarding Electrical Test Instruments can have dramatic results. When electric safety is discussed, the subjects of arc flash, shock and arc blast dominate discussions, but one question often pops up, “how to identify the location of hazards using electrical test instruments?” This question can be answered by reviewing the electrical hazards, chalking up the requirements for assessing the workplace and identifying faults using proper use of electrical test instruments.
Electrical Hazards
Electricity is one of the most serious workplace hazards in the world and can lead to shocks, burns, fires and explosions. Employees can get seriously injured or even lose their lives due to the explosions caused by electricity. In addition to the risk posed to human life, electrical hazards such as arc flash & blast can damage equipment, causing fragmented metals to fly in all directions, disrupting operation of nearby machines. Even low-energy arcs have the tendency to cause violent explosions, and serve as the ignition source of a bigger explosion.
Improper use of electrical test instruments can lead to electrocution; test instruments must be selected & utilized properly to ensure safety and verify the presence of voltage.
Selection of Test Instruments
Irrespective of the type of work you’re performing, whether it involves installation, maintenance, verification of absence of voltage, troubleshooting or similar diagnostic work, collecting accurate & consistent information is extremely vital. In order to comply with the electrical industry standards & regulations, the right test instruments must be selected & used.
Whenever voltage verification for energized & deenergized components is being conducted, the electrician must use the right instruments, applicable to the work to be performed. As a minimum, these should include:
All test instruments should have clear instructions and must be certified & labelled by an independent verification lab such as UL, CE, CSA, TUV, etc. Make sure that all meters, leads and probes are of an adequate CAT category as sometimes the only thing standing between you and an electricity spike would be leads! If you are uncertain about the equipment you’re using, not only would you put yourself at risk, but also those in your surroundings.
Use of Electrical Test Instruments
Only qualified persons are permitted to perform tasks such as testing, voltage measuring, troubleshooting, etc. due to the potential electrical hazard associated with the use of test instruments. Improper use of electrical equipment can lead to shock, electrocution as well as arc flashes.
The following requirements apply to test instruments, equipment and their associated leads, power cords and connectors:
Whenever test instruments are used for testing the absence of voltage on conductors operating at 50 volts or more, the operation of the instrument must be:
CAT Ratings
There are a total of four CAT ratings, as described below:
Global Verifications
The following is a breakdown of the various worldwide labs & test facilities that verify electrical safety equipment:
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