10 Important Precautions When Working On Low Voltage Energized Equipment
Published 05 Sep 2019
With Kind Permission of: Edvard Csanyi (Editor-In-Chief & Electrical Engineer at EEP)
For most work, the electrical equipment must be de-energized because there is a high risk of injury to workers if they work on energized equipment. It may be possible to schedule such work outside of normal work hours to limit the inconvenience.
“Sometimes it is not practicable to completely disconnect low-voltage equipment before working on it.”
For example, it may be necessary to have equipment running in order to test it or fine-tune it. In such cases, the work must be performed by workers who are qualified and authorized to do the work. They must follow written safe work procedures.
You should observe the following important precautions when working on energized equipment, but note that these are not a substitute for proper training and written safe work procedures:
1. Think ahead
Assess all of the risks associated with the task. Plan the whole job in advance so that you can take every precaution, including arranging for help in case of paralyzing shock. Consider the use of a pre-job safety meeting to discuss the job with all workers before starting the work.
2. Know the system
Accurate, up-to-date information should be available to those who work on the system. This means that you should know all equipment installed according to the valid documentation (technical specifications, single line diagrams, wiring diagrams, block schemes etc.).
Be careful, sometimes equipment stated in documentation can differ from the one installed on site – due to the replacing of old (damaged) equipment with the new with similar characteristics.
3. Limit the exposure
Have live parts exposed for as little time as necessary. This does not mean that you should work hastily. Be organized so that the job can be done efficiently.
4. Cover exposed live metal
Use insulating barriers or shields to cover live parts. Plexiglas plates can be useful.
5. Cover grounded metalwork
Grounded metal parts should be covered with insulating material as much as possible. Very important.
To read on further and see the further 5 important precautions when working on low voltage energized equipment please visit Electrical Engineering Portal
Example of Slow Motion Arc Flash 100A Disconnect showing the impact of body position in arc flash. In the video, the door comes off in less than 2 cycles showing that Personal Protective Equipment (PPE) isn’t the only thing to consider when it comes to arc flash. Body position at the point of contact is also important.
Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV/MV switchgears and LV high power busbar trunking (<6300A) in power substations, commercial buildings and industry facilities. Professional in AutoCAD programming.
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