Do your Qualified (Electrical) workers test the equipment they use to verify that a circuit is de-energized?
Testing for voltage after equipment lock-out is a key step to providing electrically safe working conditions. However, testing the equipment used to verify the lack of voltage is often overlooked. Too often, the worker pulls a voltmeter from their back pocket, tool pouch or tool box to perform this important test. This meter may have not been used for days and could have been subjected to any type of abuse during this time.
I suggest an approach that I was taught early in my career as an electrician. When testing for the absence of voltage, always use the “Live-Dead-Live” method. It’s simple and requires only a small amount of time.
Live. Before testing the circuit you have turned off, check the voltmeter on a known live source. If possible, do this on a circuit of the same voltage as the one you will test. This verifies your voltmeter does in fact work.
Dead. Perform the verification test on the circuit you will work on to make sure it is de-energized.
Live. Re-test the voltmeter on the known live source to ensure it still works.
Meters are equipment that are subject to failure no matter what brand or how expensive. They are key elements to providing a safe workplace.
Before placing your trust in a voltmeter, always make sure it still works.