Electrical Testing and commissioning -Safety Guidelines

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Risk and Safety assessment for Electrical Testing and Commissioning

Safety of testing and construction personnel should be the primary  consideration at all times. The following are some guidelines to ensure safety :

 
Electrical Testing and commissioning -Safety Guidelines

  1. Ensure that proper safety gear is used. These include safety shoes, safety helmet, safety gloves(Rubber-Electrical), Rubber mat, fire extinguishers etc
  2. Whenever work is dine on power circuits (LT or HT), all power sources must be isolated by opening and withdrawing the circuit breakers. Earthing switches should be closed or if not available local  earthing should be done.
  3. Check and double check that work is being started on the correct panel / equipment. Many accidents occur because the wrong panel / equipment is opened.
  4. Tag all breakers and switches. Use padlocks wherever possible.
  5. Whenever any work is delegated to another person, it should be only after the competence of the person has been ascertained.
  6. Be very clear and precise when giving instructions.
  7. Unauthorized personnel must be kept away from the test area. Rope off the area if necessary and erect warning signs.
  8. Before starting any test, make a precise plan, including a circuit diagram for the test.
  9. Be very care fully while using certain test equipment such as meggers, earth tester, multimeter and high or  voltage test sets. If a cable is being tested, ensure that the other end has been secured and that a responsible person has been stationed there.Electrical Testing and commissioning -Safety Guidelines
  10. Similar care is to be taken when applying voltage to the low voltage side of a transformer.
  11. Treat CT secondary circuits with respect. Do not open a CT secondary circuit when there is current following on the primary.Even when doing primary injection test , first injection 10% rated current on the primary and check all the secondary circuits, before going up to the rated current.
  12. After megger or high voltage test on nay equipment, be sure to discharge the equipment to earth after the test, This may be by connecting an insulated wire between the equipment and ground.
  13. Before any work is done a motor . ensure that the motor controller has been disconnected and tagged out.
  14. When working on any equipment,whenever possible ensure that control of the associated switchgear is local e.g. when working on a motor, keep the local /Remote switch at the switch gear in local position. Control should be returned to the switchgear only after work on the equipment has been completed.
  15. Always use proper tools and instruments. Avoid using line tester to check for supply voltage. Always use multimeter for safety propose. Ensure before use, that multimeter has been selected for the correct parameter and range and its lead are instead in the appropriate sockets on the meter.
  16. When ever temporary jumpers are required in testing, use jumpers of long length, so that even if you forget to remove them, they will get somebody else’s attention.
  17. When working on unfamiliar equipment , read the operating manual carefully before starting the work.
  18. when energizing any equipment for the first time, clear off all personal from the vicinity of the equipment. Ensure that fire extinguishers are available and ready.
  19. Paralleling of transformers is a potentially dangerous exercise. Do a phasing check at low voltage to ensure that voltage across the bus coupler breaker is zero when both transformers are energized.
  20. When applying voltage to the secondary circuit of PTs to check the connections, be sure to isolate the PTs, by removing  the control plug or secondary fuses; otherwise the PTs will get back energized. Even if only one phase PT is being checked, it is necessary to isolate the other phases as well.
  21. Before working on circuit breaker mechanism box, always first discharge the closing and tripping springs.This is done by first switching of the control power to the breaker or disconnecting its control plug, tripping the breaker ( if closed), then closing  it , and then tripping it again.It is very dangerous to work with either spring in charged condition.
  22. Never replace a blown HRC fuse with bare wire: use new HRC fuse of proper rating.