- Features | August 2, 2016
Test Before Touch
Think back in time to when you had that “aha” moment and began a statement with those two, sometimes embarrassing, words, “I thought.” Maybe you thought the door was locked and it wasn’t. Maybe you thought the car was in “Park” or in “Reverse.” Some of life’s most embarrassing moments begin with those two words “I thought.” When working in and around electricity, those “gotcha” moments can be avoided if we understand what it means to test before touch.
Treat every circuit as if it is energized until you test and then test again.
BASIC STEPS TO SUCCESS
Get your head in the game by understanding some basic principles before working on electrical equipment.
1. Understand the System:
Before work begins, we need to ensure we understand the system in which we are working. A review of the one- line diagram can help us understand the flow of power through the system. Presence of alternative sources tells us that the secondary of a switch or other overcurrent protective device (OCPD), which is usually de-energized when opened, may not be de-energized when opened. Photovoltaic, wind, or other similar systems generate electricity, so the utility may not be the only source of power on the premise. It is critical to understand what equipment must be locked and tagged in the off position.
Always be sure to check the dates of the documents being reviewed to understand the system as electrical distribution systems will change over time. The electrical system one-line diagrams are an important part of any facilities safety plan for this very reason. When changes are made to the electrical distribution system, we have to plan for those who will get engaged that have not been a part of the facility through all of the changes. They must be able to review the latest information on the facility to ensure work plans are accurate.
2. Understand the Electrical Equipment:
The electrical equipment upon which or in which work will be conducted must be understood by those performing the work. Some equipment is much more complicated than others. Know it well before getting engaged. This should include knowing the condition of maintenance as the condition of maintenance is important to understand if operating the equipment is safe. Condition of maintenance will also give us some peripheral insight to whether or not we can trust the incident energy values calculated and posted.
The electrical equipment will be used to interrupt load currents to help isolate the portion of the circuit to be worked on. Visual verification, where possible, is always advisable. Look for the blades to see them disconnected and fully open. Make sure that the draw-out equipment is completely out and in the disconnected position.
The lockout and tagout processes and procedures identified within NFPA 70E are important to maintain the system in the de-energized state. These procedures help prevent someone from closing what has been opened to establish an electrically safe work condition.
4. Proper PPE:
Wearing the appropriate personal protective equipment (PPE) for the project goes well beyond just getting dressed. Electricians must understand the incident energy that could be present, voltage levels, and a host of other details to ensure that the right PPE is selected for the job. Electrician’s should dress for an event that will hopefully never happen if they have followed all of the proper rules to de-energize the equipment on which they will be conducting work.