Electric Shock Investigations – Part 3

In Part 1, the preplanning and first response phases of an electric shock and/or arc flash incident investigation were discussed.
In Part 2, we embarked on the very important phase of an investigation and the collection of the evidence.
In this Part 3 article, the ins and outs of the analysis and interpretation of the evidence, the development of a hypothesis, the report writing and finalisation of the investigation, are all dealt with.
Our ultimate aims with the investigation should include, most importantly, preventing any further incidents and loss of life or injuries, minimising any litigation and prosecution fines, and being prepared for that litigation.

Once all the onsite and offsite evidence has been collected, begins the important next step of interpreting the evidence and developing the hypothesis that best fits the evidence.
Sequence of Events
Developing a sequence of events will help with the analysis and interpretation of the evidence. The sequence of events may start months or even years before the actual incident due to latent conditions that may have been ‘set up’ previously e.g:

  • During the initial design and/or installation of the electrical installation;
  • In the selection of the electrical equipment;
  • Through maintenance or lack thereof;
  • The establishment of procedures or work instructions that may not provide the safest options; and
  • Via training in the procedures or work instructions just mentioned.

Analysis and Interpretation of the Evidence
All the available evidence should be considered in the analysis. Of course, some of the analysis is carried out while the evidence is being collected e.g the design of the final sub-circuit to a piece of electrical equipment is suspected as contributing to the incident and so, the size of cabling to the equipment and associated protection is investigated in more detail than would otherwise be the case.
Actions taken or not taken, the people involved (actors as they are often called) or should have been involved, and any hazardous conditions and unsafe behaviours need to be all identified as part of analysis.
Any physical evidence will need to be analysed and examined in accordance with the establish procedure that was developed in the preplanning stage before any investigation is carried out. This will include any testing or examination techniques that might be construed as ‘destructive’. Any destructive investigation of evidence is likely to need approval from all relevant parties. Independent external test laboratories or consultants may be used for independent assessment of physical evidence.
The results of the analysis and interpretation will then be used to develop a hypothesis or multiple hypotheses. Keep in mind that forensic science is about testable and reproducible results regardless of who did or could have carried out the investigation. The investigator carrying out the analysis and interpretation needs to always remain unbiased regardless of who is paying for their investigative services. An external expert employed for the investigation has an ultimate obligation to the courts and must follow a code of practice which is generally called up in legislation.

Some form of Root Cause Analysis should be used to identify all the causes of the incident, including all the underlying causes. Think of the Swiss Cheese Model and how it generally has ‘holes in the various layers of cheese’ that can lead to an incident. Often the obvious cause of an incident is identified but the underlying causes sometimes get forgotten or missed. It is easy to sack the worker, the scapegoat who ‘stuffed up’ but this approach is unlikely to prevent further incidents from the same cause(s).
There are additional items that might need consideration in the analysis and interpretation and in the final report such as the inherent limitations of the methods used in the investigation or in the test instruments used, any sources of errors and their significance, etc. Even reasons for rejecting alternate hypotheses or inconclusive opinions may need to be reported but these will need reasons why they have been rejected in the final conclusions.
Analysis and Interpretation of Electrical Evidence
A detailed analysis of the electrical evidence will be needed for an arc flash event, electric shock, electrocution, and/or electrical fire. Skilled, qualified and trained electrical investigators will be needed for this.
The source of the electric shock and all the contributory factors that lead to the incident will need to be identified. Contributory factors might include compliance with standards including the Wiring Rules, legal requirements, codes of practice, policies, procedures, work instructions, arc flash labelling, manufacturer installation and maintenance requirements, or any internal requirements, etc.

Chris is analysing electrical evidence before writing his incident report

Resulting Actions
The analysis and interpretation will also need to include the resulting actions such as corrective and preventative actions. Corrective actions are those actions to CORRECT any deficiencies at the incident site whereas preventative actions are all other actions that will PREVENT a reoccurrence at the site or other sites.
A safety regulator might identify these actions to ensure the Person Conducting the Business or Undertaking (PCBU) implements

appropriate controls to prevent a reoccurrence. For a PCBU, the actions will also help to prevent a reoccurrence and hopefully mitigate any prosecution and fines.
The investigator for a PCBU may need to establish a Cost Benefit Analysis (CBA) to justify expenditure to prevent reoccurrences. The CBA will need to be approved by the PCBU and funds allocated for the control measures.
Ultimately, a written report will be required but updates are likely via the phone, in person or via video conferencing.
Confidentiality is always important throughout the investigation and into the analysis/interpretation, report writing stage and into the future. Of course, any confidential details are likely to be revealed in a coroner’s court, prosecution or if civil action results.
Initially, an internal or industry wide hazard alert may be necessary to help ensure safety on a company or industry wide basis.
Reports to the safety regulator will be required initially, or as soon as reasonably practicable, via online portals and/or via phone contact and within the required timeframe. The safety regulator will also require a final report in the appropriate format.
A brief report may be required for the management team and/or board level. This could be part way through or on completion of the investigation and report writing processes.
The report writer is likely to be the lead investigator, who may or may not be an electrical person, but he/she may delegate this duty to another. Non-electrical report writers will need to rely heavily on the electrical expert(s) for the investigation or the quality of the report will be compromised.
Written Report Content
All relevant detail will be needed in the final written report, and the report must be easily understood by non-technical people. That means that jargon must be limited, and technical electrical evidence needs to be written in plain English. Incident reports always need to be evidence based.
Reports should NOT include opinions or comments beyond the author’s area of expertise. The trap for electrical qualified writers is that comments are often made about the injuries of the shock victim. These comments are best left to the doctors for injuries or the medical examiner for deaths.
Assumptions are best left out of the report and one that is often made is that the person received a 230/240 volt electric shock. Generally, this only occurs if the shock victim contacts both active and neutral or earth conductors at the same time.
Irrelevant comments, unsubstantiated facts or personal comments about individuals are best left out of reports. The use of pronouns such as I, we, they, us, are best avoided in reports.
There must always be adequate explanation of the incident and analysis for anyone unfamiliar with the situation or the technical aspects of the incident.
Report Format
The format of the report should include an executive summary that summarises the whole report and is limited to a couple of pages. The executive summary is for time-poor readers such as upper management.
Appendices are for important information that is too lengthy for the main body of the report but must be referred to in the body of the report.

Written Report Review
The report should be reviewed technically by someone with the appropriate skills and qualifications. It should also be reviewed administratively for grammar, spelling and that it makes sense to a non-technical person.

Chris writing an incident report
Finalising all Actions
An action plan should be developed and included in the report. It is important that all actions are completed by the due dates, or another incident could occur. Action plans for a worksite will differ dramatically to those of a safety regulator.
A post investigation review is important to help ensure that subsequent investigations are handled as professionally as possible. This review could be on a personal basis or as a group in a formal setting of all investigation participants. The review might be best chaired by someone independent to the investigation or even external to the organisation. All aspects of the investigation should be considered in the review.
Counselling is likely to have started long before finalising the investigation, but it is a good to time to review if everyone that needs counselling has received it including the investigators.
One of the actions on the action plan should be to ensure the final report to the safety regulator is submitted in their required format.
Finally, any changes to internal records will need to be carried out. Training may also be needed for any changes in policies and procedure type documents.
The final parts of the electrical incident investigation include the analysis and interpretation of the evidence, developing a hypothesis of what occurred, determining the corrective and preventative actions to prevent recurrences, report writing and then finalising all the actions.
The investigator carrying the analysis and interpretation needs to always remain unbiased regardless of who is paying for their investigative services.
Some form of Root Cause Analysis should be used to identify all the causes of the incident including all the underlying causes and contributory factors.
Hazard alerts may be needed initially on a company or industry wide basis, and a detailed report will be needed with corrective and preventative actions to fix and prevent reoccurrences. The content of the final report will need to include all relevant detail and be easily understood by non-technical people.
All actions must be signed off to complete the investigation and a post investigation review is strongly recommended.
This concludes our three-part series on this topic. We are specialist trainers in this area and no one else in Australia can offer the level of expertise we include in our training courses.
Chris Halliday
Electrical Safety Advocate and Specialist Trainer

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