By Linny Folau

A temporary meter box connected by an extension lead at a flooded home in Hala‘ovave, Tongatapu. 2 March, 2014.

The threat of death by electrocution during flooding in Tongatapu’s heavily-populated areas was a concern during Tropical Cyclone Kofi over the weekend, March 1-2, as Tonga’s National Emergency Management Office (NEMO) pointed out that the power was not shut down in inundated areas. 

But flooded homeowners need to understand that they are responsible for turning their own power off, according to Tonga Power Ltd.

NEMO’s report on Tropical Cyclone Kofi this week, warns that there is a developing issue with electricity and flooding. Three teams were deployed in Tongatapu to conduct initial damage assessments after Kofi brought damaging winds and heavy rain to southern Tonga on March 1-2.

“Houses in flood prone areas seem to remain connected to the grid even when these areas are inundated and water enters the buildings,” NEMO director Leveni ‘Aho stated in their Cyclone Kofi Situation Report, released on Sunday night. “Ho’umakelikou was only town that reported to have had electricity disconnected.”

Leveni identified two houses with water entering at ‘Isileli and Sopu and water was close to entering in other instances. “The situation will need to be monitored,” he said.

Many homes in water

Electrocution is a real danger to residents of flooded areas, and homeowners need to understand they are responsible for turning their own power off, according to Tonga Power Ltd’s managers, who also stressed the dangers of having temporary meter boxes (TMBs) connected via extension leads to homes surrounded by water. 

John van Brink, CEO of Tonga Power Ltd. said today that they were aware of the concerns raised and had sent faults staff to look at these homes. “But the difficulty is there are a number of homes that are regularly under threat of flooding and householders may not be aware of the need to switch off the electricity.”

He said homeowners had the responsibility to make sure their house wiring was safe and when a house was flooded the householder should turn the power off at the main switchboard and not switch it back on until they were sure it was safe. “Which means getting an electrician to look at the wiring,” he said.

“Tonga Power has no control over the house wiring, which is bound by Wiring Regulations imposed by Government and controlled by the Electricity Commission - meaning homes have to get their wiring inspected with a Certificate of Compliance issued before it can be connected to the electricity network,” he said.

Policy

John said they had the responsibility for providing a safe network and power up to the property boundary, which is why they turned off the generators in a cyclone if there was danger of the network breaking and when live wires fell on the road.

However, it was a different situation for individual homes.

"When it gets to isolating a house or a group of houses, how do we know? Does Tonga Power disconnect selected transformers? Is it right to disconnect supply to say 40 homes connected to a transformer when say one, two or even 10 have flooding issues?"

He said Tonga Power believed there should be a policy or rules in place to help make these decisions, and so this becomes a government matter.

“We intend to take this up further with selected parties in government as well as the Electricity Commission,” John said.

He said the only way to minimize the occurrence of any fatalities would be through a widespread power shutdowns but this would have to be at the instruction from government or one of its agencies.

Main switch

"Householders can switch off supply to their homes by turning the main switch off. Tonga Power in many cases would need to switch off power to a transformer that can supply anywhere up to 50 or more homes. Failing that, we have to switch off sections of feeders, which shuts down supply to hundreds of homes and supply would have to be off for a long time, until flood waters dropped."

He said the only viable option is to switch off supply to individual homes, which is something Tonga Power has no control over.

Danger

John said the danger with houses flooded and still with power connected was that appliances may become unsafe and that exposed wiring may cause shocks and potentially electrocution. Extension leads were one example.

Rod Lowe the Distribution Manager said a new connection of a Temporary Meter Box inspected by the Electricity Commission was usually connected by an extension lead strung to the house via trees and along the ground, and in some cases the homes were surrounded by water.

He said with extension leads if the house end of the lead came in contact with the water, it would liven the area around the house if the circuit breaker did not trip, so these types of supplies should be disconnected by the customer.

The Electricity Commission and Tonga Power needed also to address this issue as TMB’s were only supposed to be connected for three-months, “after that it must be connected to the building or be disconnected and removed,” Rod said.