Tamahere tops power outage table


Power outage figures from Waipa Networks confirm what Tamahere residents have long suspected – the area has more than three times as many outages as the rest of the Waipa network.

In the last year, Tamahere people experienced, on average, a high eight hours without power compared to around three hours for the network as a whole.

The figures have been revealed to Tamahere Forum after a power outage in late April that for some locals lasted six hours.

Waipa Networks customer services manager Kerry Watson, who provided the figures to Tamahere Forum, said the biggest cause of outages is the area’s many trees.

The lengthy outage in April was caused by an uncommon failure of isolation equipment in a cabinet in Birchwood Lane. And things like equipment failure, car accidents and bad weather did cause a percentage of outages in Tamahere each year.

But by far the most frequent cause was trees interfering with the lines, Watson said.

Tree owners have obligations to ensure that their trees do not interfere with the power network.

“We have particular difficulties in negotiating tree cutting in the Tamahere area as one of the reasons residents choose the area is the trees,” Watson said. “Tree owners are therefore reluctant to have them trimmed or to take responsibility for keeping them clear of our lines.

“However, due to the particular problems in this area we are increasing our tree liaison and trimming work in Tamahere,” he said.

Waipa Networks posted a brochure about trees and powerlines to all of its customers in April and had had a good response from tree owners. Click the following link for a copy of the tree brochure(PDF): Waipa Networks trees & powerlines

“We have already trimmed two sets of problem trees in the Tamahere area,” Watson said.

Waipa Networks was having a renewed focus on tree trimming, particularly in the Tamahere area, and hoped to see a significant reduction in the number of tree-related faults, Watson said.

What the figures show

One of the key indicators of the reliability of an electricity lines company is the System Average Interruption Duration Index (SAIDI). The figure is arrived at by adding up all the customer outage durations and dividing by the total number of customers supplied to give an outage figure in minutes per customer.

Power outages in minutes per year in Tamahere and their causes
Power outages in minutes per customer per year in Tamahere and their causes

From April 2014 to March 2015 the Tamahere power feeder had a total of 896,694 customer minutes without power. There are 1850 customers supplied by that feeder and so 896,694 minutes divided by 1850 customers equals 484.7 outage minutes or around eight hours per customer over the 12 months.

However, overall on the Network, the outage figure was 172.10 minutes (around 2 hours 50 minutes) or around five fewer hours of outage than that experienced in Tamahere.

Power outages across the entire Waipa Network - five fewer hours of outages than in Tamahere
Power outages across the entire Waipa Network – in 2014-15 five fewer hours of outages than in Tamahere

The 2014-2015 year was not unique. 2011-12 was also a bad year across the network but especially for Tamahere.

On the graphs, the outages in blue are faults caused by trees, whereas the items in red include things like equipment failure, car accidents, bad weather, and unknown causes but possibly trees also.

3 thoughts on “Tamahere tops power outage table

  • June 2, 2015 at 12:57 pm

    We’ve been on Pencarrow Road for over 16 years and have noticed that the outages are at least one a month. For a while I was recording them in my diary to confirm my suspicions. Years ago Waipa told us that we were the end of the line which is why we had more outages but not sure that would cause it. Now I notice that they put in a new box at the edge of our property, knocking out part of the hedge and fence in the process (which they haven’t repaired–luckily Sam noticed and put it back before the sheep escaped). Maybe this means fewer outages now?

  • June 2, 2015 at 9:41 am

    This is interesting..
    Looking at their chart, the trees must have grown spectacularly in the last 2 years…? Hmmm..
    Or is there another reason?..
    Needs more investigation please.. can she tell us all the outages caused by trees and where they were located?.
    We are getting pretty frustrated with the continual outages.

    • July 5, 2015 at 9:34 am

      During last Saturday night the power in Riverglade Drive went off three seperate times for extended periods. Yesterday, the following Saturday morning the power went off again. We rang up Trust Power who knew nothing about it yet when we drove down Newell Road Waipa Networks were working on the poles opposite Birchwood Lane. Later what do you know, right in the middle of tea in the oven that evening the power goes off again. We ring Trust Power who know nothing about it. I drive down the road and Waipa are up the same pole. They tell me the power has to be off at tea time because Birchwood has been off all day and they are re connecting them except I later find out they were on a generator all day and Waipa choose to swap them back over at tea time.
      So thats five power outages in seven days, the service provider doesnt know whats going on in their network and the network operators people not only decieved me but choose to inconveniance everyone at the worst possible time.
      People wouldnt get upset if there was some simple communication about the planned work to resolve ongoing issues but these people are just not up with the play. Very annoying.


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