John Oates

Coroner's concerns

AI summary

Manufacturing defects in widespread porcelain tension disc insulators cause failures that can lead to dangerous low-hanging power lines, a risk compounded by insufficient adoption of detection technology.

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The evidence revealed matters giving rise to concern. In my opinion there is a risk that future deaths will occur unless action is taken. 1. The cement fill within the porcelain tension disc insulators was found to contain voids in 73% of the insulators tested. These voids were introduced during the manufacturing process. The industry was unaware of these voids until discovered during ENWL’s investigation. Porcelain tension disc insulators are used widely throughout the electricity industry – and other industries.

2. Some of the discs tested were also found to have asymmetrical pins which increased the internal stresses on the insulators.

3. Either voids alone or in combination with an asymmetrical pin create a means by which electric current can pass across the voids and lead to failure of an insulator.

4. There has now been a double insulator failure.

5. A phase-to-phase fault can lead to a low hanging line. This was not known prior to Harry’s death.

6. There will be locations across the UK which have the combination of porcelain tension disc insulators situated above equipment (such as an ASL) on which a conductor could be suspended in the event of disc failure.

7. Although at the time of the incident, there was no automatic means of detecting a low hanging line, technology now exists that can detect both these factors and which narrows the area in which the low hanging line is situated – Linesight.

8. It has also been determined that Linesight can detect that an insulator may be subject to internal stresses.

Although the failure mode was “rare and complex”, there is a risk of future deaths albeit a low one. This presents an opportunity for guidance to be given on re-assessment of risk and risk reducing measures. Although I determined that the placement of the support poles was not materially contributive to Harry’s death, there is also an opportunity for this to be considered.

Responses

1 respondent

Electricity Networks Association Other

11 Feb 2026 PDF

Action Planned

The ENA has convened member companies to improve arrangements following the death. They plan to produce industry guidance on health and safety risk assessments for low-hanging overhead lines and promote innovative monitoring technologies by September 2026. (AI summary)

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Dear Miss Gomersal,

This letter is the response from Energy Networks Association (‘ENA’) to your Regulation 28: Report to prevent future deaths, dated 19th December 2025 into the death of Henry John Oates.

We are deeply saddened by the tragic death of Mr Oates and want to express our deepest sympathies and extend our condolences to his family and friends.

ENA represents the companies which operate the electricity networks in the UK and Ireland. We support our members to meet the challenge of delivering electricity to communities across the UK and Ireland safely, sustainably, and reliably and share best practice. Our members’ duties are enshrined in many legislative provisions and in regulatory licence conditions issued by Ofgem, the industry regulator.

As you have stated, ENA was not an Interested Person (and did not participate in any way) in the inquest which you held in this case, nonetheless we recognise the concerns you have identified and aim to facilitate a pathway for our member companies to further consider and implement proactive measures.

I would like to take the opportunity to confirm that the essential elements related to the death of Mr Oates have already been shared with member companies through our member forums.

ENA has carefully considered the concerns set out in your Report to prevent future deaths and wishes to outline the actions being taken by ENA to reduce the likelihood of similar events occurring in the future. Following the immediate actions undertaken by Scottish Power Electricity North West (SP ENW) and items as referenced in your report, ENA has convened member company representatives to consider the learnings from this case and determine how existing arrangements can or should be improved.

The actions we have taken and intend to take include the following:

Objective 1: Review and improve where necessary, Safety, Health and Environment (SHE) industry standards and public safety risk assessment ENA and its members will: :

- Review and update if deemed necessary, the relevant ENA SHE Standards (including Standard 06 - Post Trip Manual Reclosing of High Voltage Electrical Distribution Circuits & Standard 09 - Distribution Network Operator Response to Reports of Low or Grounded Overhead Lines) in consideration of the information shared from this incident.

- Develop supplementary guidance to address the risk relating to overhead lines that have automatically reclosed where a low hanging conductor may exist but has not been reported or been detected. The guidance will establish a risk assessment criteria for member companies to consider, informed by industry best known and available practices. This should inform and strengthen existing ways of working and support appropriate interventions such as risk-targeted inspections or patrols, asset location data, enhanced monitoring, and other appropriate or technical solutions to proportionately mitigate foreseeable risk.

ENA will oversee delivery of these objectives and ensure they are completed no later than September 2026.

This additional guidance will support ENA member companies in reviewing and updating their own individual associated public safety risk assessments, which each company has committed to undertake and continue to review periodically.

Objective 2: Review and improve engineering evidence, asset risk awareness and promote risk-based investment ENA and its members will also:

- Develop an Engineering Technical Report (ETR) to collate and document engineering evidence on asset failure modes relevant to this incident, consolidating findings from SP ENW and concerns identified in your report, and incorporate learning from wider industry experiences. It will also capture and review other relevant or emerging failure mechanisms, providing a reference resource for ENA member companies.

The ETR will provide a clear evidence base to support ENA member companies in undertaking their own risk-based assessments and determining proportionate interventions or investment actions required, aligned to their specific asset populations and public safety risk profiles.

The ENA will oversee delivery of these objectives and ensure they are completed no later than September 2026.

Broader objectives ENA will continue to promote improvements in engineering standards and raise awareness of available and emerging innovative monitoring and detection technologies, including those referenced in your report. ENA member companies will assess the effectiveness of these solutions and share current and emerging good

practice to support assessment of asset risk exposure, development of maintenance strategies, investment planning, price control submissions, and engagement with Ofgem. Where appropriate, such technologies will be promoted through ENA’s Smarter Networks Portal or similar mechanisms to support planned, risk-based investment in potential innovative monitoring and detection solutions.

ENA will also continue to review and, where necessary, update existing ENA Engineering, SHE documentation and general advice to reflect newly identified or emerging failure mechanisms.

Summary Together, the two objectives will deliver clear, practical industry guidance to support the continuous improvement of health and safety risk assessment and interventions associated with low hanging overhead line conductors, while also providing an evidence-based framework to support informed, risk-based asset management and investment decisions by individual member companies.

I can confirm that once the above objectives as outlined are completed, ENA will produce a summary briefing for our members. The briefing will be shared with the Health and Safety Executive (HSE) to support the dialogue ENA and member companies have already started with them.

I trust that the information and response provided above will help to discharge our responsibilities in this matter.

The industry regrets any loss of life related to our activities or infrastructure and takes our duties to minimise these risks very seriously.

Report sections

Investigation and inquest

Throughout the course of my investigation into Mr Oates’ death, his family invited me to call him Harry. I shall do so throughout this Report.

Harry died on 27 October 2023 in a field at Badger Gate, Lupton, near Carnforth in Cumbria.

Following post-mortem examination, the medical cause of Harry’s death was found to be:

1(a) Electrocution

An investigation into Harry’s death was commenced on 31 October 2023.

An Inquest into Harry’s death was opened on 14 November 2023 by HM Assistant Coroner Robert Cohen. At the same time, Harry’s Inquest was suspended in opening in accordance with Coroners and Justice Act 2009 Schedule 1 Part 1 Paragraph 5 pending the outcome of external agency enquiries.

The investigation into Harry’s death resumed on 19 July 2024 and his inquest was held before me on 9, 10 and 11 December 2025. I delivered my findings, determination and conclusion on 16 December 2025.

The determination was:

On 27 October 2023, Mr John Henry Oates, who was known as Harry, was on a training run. At approximately 14:07 Harry was running on a public footpath on a field at Badger Gate when he came into contact with a low hanging 11 kv electricity conductor. Harry was killed immediately. His death was confirmed at 1835.

The conductor had been released from its usual position on 25 October 2023 at about 16.17 and became suspended on equipment lower down the pole. The conductor did not go to earth and remained live. At the time, there was no automatic means of detection of the low hanging line. The low hanging line had not been reported.

The low hanging line was caused by the simultaneous failure of two porcelain tension disc insulators on 25 October. The root cause of the insulator failures was voids in the cement fill. Voids in the cement were not known at the time. These voids allowed internal electrical discharge. This caused the electrical failure of the first insulator. This failure led to the top cross arm becoming energised. This caused the second insulator to fail electrically and mechanically. The live conductor was released and suspended from the lower cross arm on the supporting pole. This sequence of events was rare and complex. It lead to the conductor become low hanging yet remaining energised.

The conclusion of the inquest was:

Harry died due to a rare and complex sequence of events

Circumstances of the death

On 27 October 2023, at about 11:50, Harry departed his parents’ home for a training run. Whilst crossing a field at Badger Gate, at approximately 14:07, Harry came into contact with a low hanging 11kv electrical conductor wire which had fallen from its usual height at over 8 metres at pole 660901. Harry was located at 16:S34 by his father and brother who raised the alarm. Emergency services and ENWL attended the scene. Harry had sustained injuries inconsistent with life. His death was instantaneous. Harry’s death was formally confirmed at 18:35.

ENWL is the Distribution Network Operator (“DNO”) responsible to the electrical conductor.

ENWL and HSE carried out an investigation into the incident. It was found that:

On 25 October 2023 at approximately 16:17, there was a simultaneous failure of two porcelain tension disc insulators on pole 660901 in the field at Badger Gate.

This caused the 11kv conductor wire to become released from its usual position. The length of the conductor wire was extended by the “dropper”. The conductor became suspended on a cross arm further down the pole hosting an Auto Sectioning Link.

This resulted in a “low hanging line”. As the line did not go to earth, it remained energised.

The fault on pole 660901 was detected as a “phase to phase” transient fault and automatically reconnected in accordance with ENWL procedure. At the time, a phase-to-phase fault was not known to lead to a low hanging line.

Evidence was consistent that, at the time, there was no automated mechanism to detect a low hanging line and that electricity industry relied on low hanging lines being reported by members of the public. The low hanging line was not reported to ENWL until after the incident.

As part of ENWL’s investigation into the incident, approximately 260 insulators were examined and tested. 73% of insulators were found to contain voids in the cement fill of the porcelain insulators. These voids were introduced during the manufacturing process. The presence of voids was not known until identified through ENWL’s investigation despite the insulators having been used throughout the electricity (and other) industries since the 1950s.

The voids in the cement fill led to microcracking and subjected the cement to environmental factors. The voids and microcracking affected the cement integrity and created “air gaps” which permitted internal electrical discharge.

Further, the investigation also found that a number of insulators had asymmetrical pins. I found that the insulators in question were likely to have asymmetrical pins as well as voids but it was not possible to determine the contribution of the asymmetrical pins to the insulator failure.

The root cause of the insulators’ failure was voids within the cement fill.

The first insulator failed electrically due to an internal flashover / short circuit. This caused the steel cross arm of the pole (to which the insulators were fixed) became energised. The second insulator consequently failed electrically and mechanically.

The evidence was that whilst insulator failures were recognised, a double insulator failure had not been known to previously occur.

The poles and insulators were inspected in accordance with procedures consistent with industry standards. There were no relevant concerns following the last inspection in August 2023. There were no visual signs that the insulators had a fault. There was no means of testing the insulators in situ at the time.

The electricity conductor was above the minimum height required and that the pole span was within the maximum span permitted by the relevant British Standard. Placement of the supporting poles depends on a number of factors. The evidence of the HSE inspector was that the placement of the poles did not cause him concern.

The failure mode was described in several ways by the witnesses including “first to our knowledge and not experienced before”, complex, unique, very unique, not known, unprecedented, rare and extremely rare.

I determined that the failure mode, described above, was a rare and complex sequence of events which directly caused Harry’s death.

I heard evidence of the steps that ENWL had and were taking as a result of its investigations:

1. The use of porcelain insulators was stopped.

2. ENWL estimated that, within its network, there are approximately 8,000 locations where porcelain insulators are present above equipment affixed lower down the pole on which a conductor may become suspended. Where maintenance work is required at those locations, ENWL will replace the porcelain insulator. ENWL intends to embark on a replacement program but this requires liaison with OFGEM due to the extent of the work and outages required.

3. It is now recognised that a phase-to-phase fault can lead to a low hanging line; this was not the case prior to the incident. Although patrols were not required prior to Harry’s death, ENWL now carries out patrols of lines affected by a phase-to-phase fault within 48 hours.

4. ENWL will also consider the placement of support poles relative to a right of way in future. I did not find that the placement of the support poles was contributor to Harry’s death.
5. ENWL has installed a system called Linesight across 77% if its network. It intends to install Linesight across 80% of its network (some parts of the network are not suitable for Linesight installation). Linesight is new technology which relies on detection and AI. Linesight is able to detect low hanging lines. Further, Linesight can also detect if insulators are becoming electrically charged due to an internal issue.

I heard that ENWL had shared the results of its findings with OFGEM, HSE, ENA and other DNOs.

However, whilst witnesses could outline what they believed was being done by other DNOs, they could not provide a full overview of action being undertaken by others.

The ENA was not an Interested Person in Harry’s inquest. It did attend nor did it provide any evidence to me – and was not asked to do so.

Action should be taken

The ENA is the electricity networks industry representative and supports its members to deliver energy safely and share best practices. It has a Safety Health and Environment Committee and issues best practice to the industry.

I again stress that the ENA was not an Interested Person in Harry’s inquest. It did attend nor did it provide any evidence to me – and was not asked to do so.

Copies sent to

OFGEMAnd the following DNOsScottish & Southern Electricity Networks SP Energy Networks Northern Powergrid UK Power Networks National Grid ESB Networks Manx Utilities Northern Ireland Electricity NetworksWhilst I appreciate that ESB Networks, Manx Utilities and Northern Ireland Electricity Networks do not fall within the Coroner’s jurisdiction, in my view, it is appropriate to bring this Report to their direct attention

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