Root Cause Analysis

YOUR need to eliminate the CAUSE of the problem...
Acton EMS has a huge database to trouble shoot with future prevention.


A root cause analysis is a methodology to identify the root cause of a given problem or issue, by asking a serious of questions.  These questions prompt us to consider different viewpoints.  Each of these viewpoints will either confirm or conflict with the initial viewpoint.


It is a proactive technique to eliminate reactive thinking and clearly see what caused what to happen.

Why it's useful - Root Cause Analysis is helpful

  • To prevent a recurrence of the same failure
  • To ensure that valuable time is not wasted by implementing solutions to symptoms rather than causes.
  • As a teaching aid for technicians - we learn deeper thinking about how a machine works by thinking through what caused this one to fail.
  • To prevent a recurrence of other similar Assets.

HOW to use it... It is simpler to use than it looks !

  1. Start by looking at the most obvious failed component
  2. Next ask did this fail due to the failure of another internal component
  3. Yes to Q2 goes back to 1
  4. No to Q2 asked the question did this fail due to an external influence
  5. Yes to Q4 asks - Was this external influence caused by a different external influence
  6. No to Q5 take you to conclusion
  7. Yes takes you back to the 5th bullet
  8. If you get a maybe you have to go back to 1st bullet

Conclusion is that the internal/external cause has been identified.  We need to decide what to do to prevent its recurrence.

EXAMPLE - Root cause of Failure

  • Winding wire enamel has been overheated  in an even pattern (Black is>250 Deg C)
  • Did this happen due to another internal component failure
  • No the normal colour winding was still intact with good connections to the motor
  • Terminals, and would have taken current if any was applied.. clearly had little or none because it was not overheated
  • No on Q2 This appears to have failed due to loss of supply to the one clean phase of the motor
  • Yes to Q4 Was the loss of supply due to another external influence (gathered information from the trouble shooter he said the one fuse link was blown, was a green fuse, not motor rated
  • Ask was this wrong fuse due to some other external influence
  • Yes to Q7 the operator overloaded the motor last month and blew a fuse and put in the only fuse he had
  • Is there any other external reason which caused the operator to put in the wrong fuse
  • Yes - The overload device was set 20% high and did not operate
  • Why was the overload device set high? Production had been testing a new product at its top speed an dit kept tripping out
  • Was there any other external cause beyond this - No


  • Train the operator to call the Electrician, or fit fuses of the same type as removed.
  • Put a sign on the fuse board “when replacing fuses only fit identical rating fuses”
  • Train the Operator and Electrician to check the fuse rating if making adjustments to overload ratings.
  • Fit a more modern overload - capable of tripping when a fuse blows, even when the rating is adjusted up.