Sunday, January 17, 2021
Anyone who makes their living by working with electricity quickly develops a healthy respect for anything with even a remote chance of being "live." Yet the pressures of getting a job done on time or getting a mission-critical piece of equipment back online can result in carelessness and uncharacteristic mistakes by even the most seasoned electrician. The list below was developed as a quick reminder of what not to do when taking electrical measurements.
1. Replace your meter's original fuse with a cheaper one. If your digital multimeter meets today's safety standards, that fuse is a special safety sand fuse designed to pop before an overload hits your hand. When you change your meter fuse, be sure to replace it with an authorized fuse.
2. Use a bit of wire or metal to get around the meter's fuse altogether. That may seem like a quick fix if you're caught without an extra fuse, but that fuse could be all that ends up between you and a spike headed your way.
3. Use the wrong test tool for the job. It's important to match your digital multimeter to the work ahead. Make sure your test tool holds the correct CAT rating for each job you do, even if it means switching meters throughout the day.
4. Grab the cheapest meter on the rack. You can upgrade later, right? Maybe not, if you end up a victim of a safety accident because that cheap test tool didn't actually contain the safety features it advertised. Look for independent laboratory testing.
5. Leave your safety glasses in your shirt pocket or on your forehead while you are taking test readings. Take them out. Put them on. It's important. Ditto insulated gloves and flame-resistant clothing.
6. Work on a live circuit. De-energize the circuit whenever possible. If the situation requires you to work on a live circuit, use properly insulated tools, wear safety glasses or a face shield and insulated gloves, remove watches or other jewelry, stand on an insulated mat and wear flame-resistant clothing, not regular work clothes. Troubleshooting does not always have to be done live. Many things can be trouble shot using continuity. Know when to test live and when not to.
7. Fail to use proper lockout/ tag-out procedures.
8. Keep both hands on the test. Don't! When working with live circuits, remember the old electrician's trick. Keep one hand in your pocket. That lessens the chance of a closed circuit across your chest and through your heart. Hang or rest the meter if possible. Try to avoid holding it with your hands to minimize personal exposure to the effects of transients.
9. Neglect your leads. Test leads are an important component of DMM safety. Make sure your leads match the CAT level of your job as well. Look for test leads with double insulation, shrouded input connectors, finger guards, and a non-slip surface.
10. Hang onto your old test tool forever. Today's test tools contain safety features unheard of even a few years ago, features that are worth the cost of an equipment upgrade and a lot less expensive than an emergency room visit.
11. Stake your life on the effectiveness of a proximity tester alone. Proximity testers are useful. We have previously banned them E Light Electric Services because so many personnel continued to use them exclusively without doing a follow-up test with a solenoid tester or DMM to verify the absence of voltage. We do allow proximity testers now, but they are to be used only as a preliminary test and you have to do a follow-up test with a solenoid tester or a DMM to verify the absence of voltage.
12. Fail to do a Live-Dead-Live test. Please remember all testers fail. Electronics fail, Solenoid testers with true solenoids have had the least chance to fail but recent changes to NFPA 70E require live - dead- live testing for solenoid testers also. ALL CIRCUITS MUST BE LIVE-DEAD-LIVE tested before an electrically safe work condition can be achieved.
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