An unusually high number of problems with power plinths in the Western Bay have firefighters baffled.
Fire Service figures released to the Bay of Plenty Times show firefighters in the Tauranga-Kawerau fire district have been called to 17 fires or faults involving power plinths since the start of 2011 - the most callouts recorded by paid firefighters in the country.
There were 15 power plinth incidents recorded in the North-West Auckland fire district and 10 in the South Auckland district during the same period. There were none in the South Island.
The latest fire was yesterday on the corner of Cameron Rd and 16th Ave when a plinth went up in smoke after a courier van backed into it about 12.40pm. Brian Roderick heard a boom as the box short-circuited and looked outside to see metre-high flames and smoke. "It was quite spectacular," he said.
Greerton Fire Service station officer Neil Brown has been in the Fire Service for almost 23 years but had never attended a call regarding a power plinth until he moved to Tauranga about five years ago.
Since then he has been to at least four callouts where the box has been engulfed in flames.
"I moved down here a while ago and I noticed that there seemed to be a high incidence of power plinth fires so I've been tracking it. It does show that we do have a high incidence of it," he said.
Cars crashing into the boxes were sometimes the cause but Mr Brown said that did not seem to be the case with any of the call-outs he had been to.
People should never try to put out electrical fires with water and should call the Fire Service if they see smoke or flames coming from a power plinth, Mr Brown said.
Bay of Plenty fire safety officer Jon Rewi said the boxes handled high currents and fed a number of houses. It is possible they could loosen over time like all power connections, he said.
"Electrical currents cause vibrations which in turn loosen connecters ... Generally, when one walks past a plinth you won't notice it unless it's humming. Apparently they aren't meant to hum, if they are then it's likely there are loose connections inside. This causes heat, shorting, then fire."
Mr Rewi said he could think of no reason there should be more problems with the boxes in the Bay of Plenty than anywhere else. Powerco network operations manager Phil Marsh said there were more than 20,000 pillar boxes in the Tauranga area and they were inspected every five years.
Power plinths
Rectangular, green, plastic boxes with rounded corners.
Usually found on grass verges on the road side.
Part of the underground power network.
They split the main power feed and send power to houses.