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.
5. Proper Test Equipment:
Use the right tool for the job. Selecting the wrong test equipment could be the hazard. Proper selection and use of test equipment is a must for safety sake. In addition to having selected the right test equipment, it must be working properly.
Using a test instrument is not a trivial task. A qualified employee will understand how to select the right instrument for the job and understand the limitations of each test instrument available. In addition, a qualified employee must be able to demonstrate proper use. Applying this equipment beyond their rating is no different than applying other electrical equipment beyond their rating, and it could result in injury or death to an employee if done improperly.
6. Your plan:
Before work begins, a work plan and scope must be understood by all involved.
Communicating and following a plan is very important. When things don’t go as planned, practice the stop work method and rethink the plan. It’s better to voluntarily stop work than to have work stopped for you by an event.
7. Test Before You Touch:
When all steps have been completed in your work plan by the book, trust none of it and test before you touch. Treat every circuit as if it is energized and take nobody’s word for it. NFPA 70E tells us to test each phase conductor or circuit part both phase-to-phase and phase-to-ground. Before and after each test, we are told to determine that the test instrument is operating satisfactorily by verifying on a known voltage source. This does not mean that you have to test on the same voltage level that you are working on. From a safety perspective, testing your voltage meter on a lower voltage system will accomplish the verification process that the device is working.
The Standard for Electrical Safety in the Workplace, NFPA 70E, tells us that an electrically safe work condition is when an electrical conductor or circuit part has been de-energized, separated from energized parts through lockout/tagout procedures in accordance with established standards. This document goes on to advise us that we must test to ensure there is an absence of voltage, and if determined necessary, we must ground that circuit to avoid a future hazard.
Understanding how to establish an electrically safe work condition is critical and called out in the definition of a qualified person within NPFA 70E. Section 110.2, which focuses on Training Requirements, tells us that a qualified person has to be trained and knowledgeable in an effort to avoid electrical hazards. Employees must be able to select appropriate test instruments and demonstrate how to use them to verify the absence of voltage. Remember to never trust, and test before you touch.
As always, keep safety at the top of your list and ensure you and those around you live to see another day.
Thomas Domitrovich, P.E. is VP of Technical Sales for Eaton’s Bussmann business within the Circuit Protection Division of Eaton Corporation. Thomas is based out of St. Louis, MO, and has more than 25 years of experience as an Electrical Engineer. He is a LEED Accredited Professional and a licensed Professional Engineer in the state of Pennsylvania. Thomas is active in various trade organizations including the Independent Electrical Contractors (IEC), International Association of Electrical Inspectors (IAEI), Institute of Electrical and Electronic Engineers (IEEE), National Electrical Manufacturer’s Association (NEMA) and the National Fire Protection Association (NFPA). Thomas is Principle member on Code Making Panel 2 for the National Electrical Code (NFPA 70) and an Alternate member on NFPA 73 for electrical inspections of existing dwelling units both representing NEMA.