The NSW branch of the CEPU claims Optus allowed reserve batteries designed to power its network during outages to drain despite having crews and back-up equipment available to recharge the units.
According to Energy Australia, the outage -- caused by the failure of its Hunters Hill substation --started at 5 pm Wednesday evening, leaving around 30,000 homes throughout Lane Cove, Gladesville, North Ryde and surrounding suburbs without power until 4.30 am Thursday morning.
It's understood that, unlike Telstra's exchange equipment, which can be powered by back-up generators during power outages, Optus' network nodes rely on battery packs that need to be replenished every eight to ten hours.
However, CEPU organiser representing NSW Optus technicians, Alice Salomon, said that during the Hunters Hill outage the carrier fell back on maintenance clauses in telecommunications regulations rather than its power back-up units.
According to Salomon, crews on standby to recharge the batteries were sent home.
"[Optus] just said 'we're in a telephony window', so instead of getting on the ball straight away, they were just hoping the power would kick back in -- but it didn't, so when people went to pick up their phone in the morning, they had no telephone line," claimed Salomon.
Optus yesterday conceded that it stopped using its back-up battery units at 11pm leaving some customers without service for around 5 hours overnight.
However a spokesperson for the carrier said it was facing a tough decision:
"We ceased the use of our battery back-up units because it was uncertain when Energy Australia would have its power restored in the area," said the spokesperson.
Optus, calculating that fewer people would have used their phones in the wee hours of the morning, chose to ration its battery back-up capacity.
"We had to make sure that there was sufficient battery back-up from 7am the following day in the event that power was not restored by Energy Australia" said the Optus spokesperson, instantly raising questions about the carrier's capacity to cope with the prolonged power outages.
The CEPU claims that carrier's maintenance crews are trying to get by with too few resources.
"Multiple nodes would have gone out when the [Hunters Hill] substation went down and [Optus] just don't have enough equipment to fix those situations...the entire back-up system is pretty poor," said Salomon.