Improper heater wiring system found to have caused death of teen by electrocution while showering

The incident, which happened two years ago, had prompted the Housing Board to remind its contractors to issue a warning to residents in the event that such three-pin plugs are found, in addition to advising residents to test their home’s circuit breakers on a monthly basis by pushing the test button and observing if the button trips.

Following the completion of the Home Improvement Programme a year prior to the incident, Yao Bin’s mother, Madam Zhang Aiyan wanted to have a new water heater installed in their home.

She sought the services of an electrical subcontractor from JL Engineering Construction to carry out the installment. The worker had connected the heater to a three-pin plug, which was later tested by his supervisor, Mr Ooi Kah Heong who found that the entire wiring system was functioning as intended.

Contrary to the work done by Mr Ooi and his subordinate, three-pin plugs and regular wall sockets should be connected directly to a special switch that has a higher capacity, compared to the one used by the electrical workers.

Mr Ooi testified at the inquiry that while he recognised that wiring a water heater to a three-pin plug poses a safety hazard, he cited his positive “experience with more than 30 HDB blocks,” in which “almost 78 per cent of water heaters were connected to three-pin plugs.”

However, he said he would usually notify the owner of a unit undergoing the HIP prior to carrying out the work, and in the case of Yao Bin’s family, he claimed to have not been able to do so as he never met them.

The coroner’s inquiry also found that the cable connecting the neutral and earth terminals in the plug was loose, and that the neutral and earth cables had melted and fused together. The latter cable was also connected to the casing of the heating tank, which was connected to the shower-head by a metallic hose.

This would result in full circuit as the electric current flow went into the tank’s casing, through the hose, then striking Yao Bin’s body, before finally reaching the wet ground, according State Coroner Kamala Ponnampalam, adding that the current that went through Yao Bin’s hand was 0.95A, the magnitude of which was fatal.

She said this “unfortunate misadventure” should pose as a warning for contractors and electricians to exercise great caution and sound judgement prior to carrying out work that poses a clear safety hazard, adding that “they ought to alert the resident to the potential dangers.”