Choosing and using test equipment correctly is critical
- Your company has established specifications for testers. Make sure equipment meets the conditions that will be faced in the field. Limiting the number of suppliers and models will simplify training.
- Provide training. Make sure employees know how to use the tester. Have them read and follow all manufacturer’s instructions. Seek the assistance of someone who has used the tester before. Manufacturers often provide schools to train users. Training should cover the hazards and limitations of each instrument you plan to use.
- Limit the use of multimeters. Analog and digital multimeters have manual settings. A common problem is that employees switch to an ohmmeter or ammeter setting, instead of voltage, and then connect to a voltage source. To avoid this human error, consider using single-function voltmeters or other instruments that don’t depend on manual settings. Also, avoid meters that have manual test lead plug connections. Limiting manual options reduces the opportunity for operator error.
- Where possible, know the voltage levels that may be carried by the wires or equipment that you will be testing. Do not depend on electrical diagrams. When working with equipment, follow the wires back to the source and look for the voltage.
- Select the appropriate tester or setting. Testers are designed for a specific voltage range. The tester or setting should match the voltage of the equipment or lines you will be working on or near. When you are unsure, always select for the maximum voltage. Start with the highest setting or instrument and reduce one step at a time until a reading is achieved.
- Do not exceed an instrument’s limitations. Many solenoid-plunger-type testers have a thermal duty cycle limit. If you exceed these limits, the solenoid coil could fail. This instrument cannot be used for continuous service.
- Retire obsolete instruments. Review your inventory to identify these instruments. Many instruments often found in the field predate recognized safety standards needed to prevent accidents.
- Know the equipment you are testing. Stored energy sources, such as capacitors, and the possibility of back feed should be tested. Knowing the equipment will enable you to test properly for all hazards. Read all manufacturers’ instructions and contact the manufacturer for more information.
- Always wear the proper protective equipment when testing or working near energized parts. The National Fire Protection Association (NFPA) Standard 70E stipulates what equipment is necessary based on the hazard level. It should be used as a reference. A quick guide, the NFPA 70E Personal Protective Equipment (PPE) Selector, to the standard and equipment needed is available from the National Electrical Contractors Association in an interactive CD format and a printed field guide.
O’CONNOR is with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. Based in Waverly, Pa., he can be reached at 607.624.7159 or by e-mail at firstname.lastname@example.org.