Have eyes in the back of head…
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.
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 usefull.
5. Cover grounded metalwork
Grounded metal parts should be covered with insulating material as much as possible. Very important.
6. Limit the energy to reduce the risk
All practical steps should be taken to ensure that the fault current at the point of work is kept as low as possible while the work is in progress. For example, when measuring voltage, do it on the load side of the circuit-protective devices with the smallest current rating.
Current-limiting devices can be used to reduce the risk of an arc flash.
7. Remove metal stuff
These could cause a short-circuit where small clearances are involved. (If it is necessary to wear medic-alert bracelets, secure them with transparent surgical or adhesive tape or rubber bands.)
8. One hand, face and body to side
Use one hand with your face and body turned to the side when operating a safety switch. Limit possible injuries by not placing body parts directly in front of energized equipment when there is danger of an arc flash.
9. When you’re in awkward positions…
Avoid electrical contact when working in awkward positions. If you must work in an awkward or unbalanced position and reach with your tools, use insulating cover-up material on the tools to avoid contact with live conductors.
10. Equipment and clothing
Use the correct safety equipment and clothing. Remeber: gloves, clothes and shoes.
Reference: Electical Safety at Low Voltage – penticton.ca