Transpower and Vector welcome Penrose inquiry report

26 November 2015

Transpower and Vector today welcomed the Electricity Authority report into last year’s Penrose substation fire released by the Minister of Energy and Resources, Hon Simon Bridges.

Following the incident, Transpower and Vector embarked on a thorough investigation, including engaging an international cable expert, to identify the cause of the fire and power outage which affected Auckland’s eastern suburbs.

The cause of the fire was found to be an electrical failure of a transition cable joint in a Vector 11 kV cable, within a cable trench crossing Transpower’s 220 kV Penrose switchyard.

Transpower and Vector Chief Executives Alison Andrew and Simon Mackenzie said that both organisations recognise the disruption that the outage caused and apologised to those affected by the incident.

Vector and Transpower have been working together to review what happened and identifying actions to ensure this type of incident is prevented from occurring again.

Despite high levels of reliability on the Auckland and national electricity network, these types of events do occasionally occur on infrastructure networks – both in New Zealand and around the world.  However, there are a number of learnings from the incident and the focus has been on identifying and resolving issues throughout the investigation process. As a result, many of the recommendations outlined in the report have either been completed, or implementation is well underway.

Alison Andrew said that since the incident, Transpower had undertaken a review of all of its critical sites where there may be a similar configuration of assets as at Penrose.

“We have around 169 substation sites around the country and a few of these have similar criticality to Penrose. Risk assessments have been undertaken at these sites and we are confident that the assets are in good operational order. We are systematically working through our other substations with our customers,” she said.

Vector has completed key recommended actions including an inspection of all areas on its network where there are transition joints in air (similar to those at Penrose), with mitigation works largely completed. 

The Electricity Authority inquiry report identified a number of recommendations for both Vector and Transpower.

Both organisations have accepted these recommendations and teams have put in place a programme of work to address these. Developments are also currently underway at the Penrose substation to add further diversity and segregation of power supply from the site.

Mr Mackenzie said that it was important that the lessons learned from the incident were shared within the industry. “We have learned some valuable lessons and we hope the industry as a whole will benefit as a result.

“Vector does want to acknowledge the disruption caused by the Penrose outage by making a service level payment to affected customers. It’s simply the right thing to do in this case.” he said.

Details of how to apply for the Vector service level payment from 2 December are available at or by calling 0508 4 PENROSE.

The Electricity Authority's report can be found here.

For further information, please contact:

Rebecca Wilson, Corporate Communications Manager, Transpower on 021 578 608

Sandy Hodge, External Relations Manager, Vector on 021 579 522


Key facts

  • In the early hours of Sunday 5 October 2014, a fire was identified at the Penrose substation, resulting in a major outage in parts of Auckland.
  • The cause of the fire was an electrical failure in a cable transition joint.
  • The fire took around eight hours to extinguish with a further four hours to make safe and restore supply.
  • The majority of consumers were reconnected that day. By 8am the next morning, 73% were restored.
  • Transpower and Vector appointed three independent industry experts to undertake an initial technical investigation into the cause of the fire.
  • The Minister of Energy and Resources requested a ministerial inquiry into the incident to be undertaken by the Electricity Authority (The Authority).
  • Transpower and Vector commissioned a UK-based international technical expert in power cables to produce a report into the incident, which was provided to the Electricity Authority/Minister of Energy and Resource.
  • Transpower and Vector prepared a joint investigation report into the incident which helped to inform the review undertaken by the Authority.
  • The Electricity Authority has accepted many of the findings and all of the recommendations in the Vector/Transpower report. The Authority has also relied on and drawn from the CCI (the international cable expert) report in their inquiry.
  • The independent cable expert has concluded that the cause of the fire was rare.
  • It has been very important to both Transpower and Vector to make improvements and address any issues as throughout the investigation, rather than wait for the final report. As a result, many of the recommendations made are already well underway.