Electric Shock Investigations – Part 2

In Part 1, the preplanning and first response phases of an electric shock and/or arc flash incident investigation were discussed in the context that Australia records on average, one electrocution/related fatality per month, and one in every three of these victims belongs to the electrician community. We should also keep in mind that in many cases, if not most, electric shock incidents go unreported.

In this article (Part 2), we embark on the very important phase of an investigation, the collection of the evidence.
An incident investigation should have outcomes and conclusions that are the same regardless of the lead investigator or the remainder of the investigation team. The scientific method of investigation should be used to ensure consistent and repeatable results.
The investigation needs to be systematic, objective and comprehensive. The investigators need to come into the investigation without preconceived ideas and free of any biases. Any conflicts of interest should be noted and discussed. These conflicts of interest may or may not affect the investigation team, but they do need to be considered.
The company’s investigation procedure, established in the preplanning phase, will need to be followed throughout the investigation.
The investigation team may not have the required expertise for all or parts of the investigation and so an expert witness may need to be engaged.
In such situations, the expert witness has an obligation to comply with an expert witness code of conduct. This is generally legislated in each Australian state. Code requirements include the format for an expert witness report, a general duty to the court and to work cooperatively with other experts if needed. An expert witness has a paramount duty to assist the Court impartially on matters relevant to the expert witness’s area of expertise and not to another party including the party retaining the expert witness.
The person conducting a business or undertaking (PCBU) may engage an expert witness for the investigation to help ensure impartiality and so outcomes are independently determined, even though, the business may have adequate expertise in-house.
Motivations for an investigation and outcomes from that investigation will depend on the party involved. The PCBU should be seeking to prevent recurrences, minimise downtime, minimise the extent of any prosecution, minimise any increase in workers comp fees, etc, etc. Whereas an electrical safety regulator will be making sure the PCBU puts adequate controls in place to prevent recurrences but will also need to consider whether prosecution is warranted.
Safety throughout the investigation will need to be ensured, and scene disturbance, or lack thereof, should be managed.
PCBU investigations are likely to need the approval of the safety regulator as evidence is likely to be disturbed through the investigation. Of course, the safety regulator may wish to investigate before any other investigation. Combined investigations between the PCBU’s and the electrical safety regulator’s investigation teams may also occur depending on the relationship between the two parties.

Barricades and/or security guards may be needed to prevent unauthorised entry during the investigation

An initial visual inspection of the incident scene will help the investigation team get a feel for what has occurred and how the investigation should be structured.
Generally, the investigation team will get one chance at the incident scene and so all available evidence should be collected for later analysis. Unimportant or superfluous evidence may be discounted later, but better to have collected the evidence than not. Also, keep in mind that investigators are human and may miss collecting some evidence but hopefully not with good training. Contamination of the evidence not yet collected should be minimised throughout the investigation.
A team approach helps to ensure all available evidence is collected.
For an electrical incident, testing will generally be required. Isolation and de-energised testing will need to be carried out and ‘live’ testing should only be carried out if de-energised testing proves fruitless. “Live’ testing, if needed, with high input impedance multimeters can distort the evidence and lead to incorrect conclusions. Electric Shock Investigation Kits with filters manufactured to AS IEC 60990 will help to prevent incorrect conclusions.
There are various methods to collect the evidence including written or dictated notes. Sketches, photos and videos provide other means of collecting evidence. Lots of photos will be better than less and video helps to collect a lot of visual evidence in a short space of time. Video cameras may also be used to capture electrical testing and other parts of the investigation. Drones can also be used for plan view photos or videos.
Cameras should have the metadata turned on to capture the location where the photo was taken. Notes about each photo can be useful. Videos can also capture narration of what is occurring at the time the video was taken. Care is needed to prevent recording unnecessary and perhaps derogatory comments.
Backing up electronic data, such as photos, is a must before leaving the site to prevent loss of evidence if things go wrong such as might occur if a memory card became faulty.

Daniel is proving de-energised before the electrical incident investigation begins

Sketches of all relevant equipment and locations of those at the site will be useful. Nameplate details of equipment will be needed to check and ensure the equipment was compliant with Australian Standards. The electrical installation will need to be checked for compliance with the version of AS/NZS 3000 Wiring Rules, that was in place at the time of the installation or modification.
Physically evidence may need to be collected, stored and managed through a chain-of-custody process in accordance with the investigation procedure previously mentioned. Suitable packaging and labelling will be required for any physical evidence. Electronic evidence, such as photos, will also need appropriate storage and labelling.
Taking witness statements will be part of the evidence collection process and this needs to occur before memories fade or collusion occurs. Interviewing is another topic in itself.
Evidence is likely to include where all personnel were and what they were doing, the weather conditions and time of day, etc.
To help minimise any deficiencies in an onsite investigation, a forensic digital twin, a snapshot in time, of the incident scene may be harvested by contractors using special equipment. The twin should be captured as soon as possible after an incident and can be used to view parts of the incident scene later and may be used to run simulations and animations to test theories and hypothesis.

Off-site evidence may also need to be collected such as training records, maintenance records, arc flash studies, protection coordination studies, installation plans, safety procedures, safety committee minutes, etc.

Chris is collecting evidence such as nameplate
details and location of all equipment. He has
previously collected photos and video evidence as
well as carried out electrical testing.

Investigators need to remain impartial and carry out a systematic, objective and thorough investigation. Investigation team members need to declare any conflicts of interest and perhaps be replaced on the investigation team if necessary.
Expert witnesses may be required if additional expertise is needed. The expert witness needs to remain impartial at all times as their obligation is to the courts.
All available evidence needs to be collected as part of an electrical incident investigation, but testing de-energised needs to occur before the investigation begins to ensure safety and compliance with legal requirements.
Evidence to be collected will include photos, video, notes, sketches, witness statements, etc, and any off-site evidence such as installation records, maintenance records, training records, etc.
This Part 2 article provides some insight into the evidence collection part of an electrical incident investigation.
Don’t hesitate to contact us to discuss any training needs or issues involving electrical incident investigations.

Chris Halliday
Electrical Safety Advocate and Specialist Trainer

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